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Binary systems comprise approximately 15 per cent of the near-Earth asteroid population, yet thermal-infrared (IR) data are often interpreted for these bodies as if they are single objects. Thermal-IR light curves of binary asteroids (3905) Doppler and (175706) 1996 FG3 are analysed using an adaptation of the Advanced Thermophysical Model, deriving new constraints on their thermal inertias as |$\Gamma = 114 \pm 31\, \, \mathrm{J}\, \mathrm{m}^{-2}\, \mathrm{K}^{-1}\, \mathrm{s}^{-1/2}$| and |$\Gamma = 142 \pm 6\, \, \mathrm{J}\, \mathrm{m}^{-2}\, \mathrm{K}^{-1}\, \mathrm{s}^{-1/2}$|⁠ , respectively. We determine that this adapted model is suitable for binary systems where their primary rotation to secondary orbit period ratios can be approximately characterized by small integers. Objects with more complex orbital states require a model with alternative temperature convergence methodologies. Thermal inertia is shown to have a strong effect on binary thermophysical light-curve morphology, introducing significant modulations both inside and outside of mutual event times. The depths of eclipse events are shown to be suppressed at longer wavelengths due to the sensitivity to cooler parts of the surface, meanwhile surface roughness is shown to have little effect on the thermal light-curve morphology. A proof of concept model for the (65803) Didymos system is demonstrated, showing how such a binary model could be used to study the system during the European Space Agency's Hera mission, and the applicability of this adapted model to NASA's Lucy mission is also briefly discussed. [ABSTRACT FROM AUTHOR]

Asteroid 2016 HO |$_3$|⁠ , a small asteroid (<60 m) in super fast rotation state (⁠|$\sim$| 28 min), and is the target of China's Tianwen-2 asteroid sample-return mission. In this work, we investigate its structural stability using an advanced soft-sphere-discrete-element-model code, dembody , which is integrated with bonded-aggregate models to simulate highly irregular boulders. The asteroid body is numerically constructed by tens of thousands particles, and then is slowly spun up until structural failure. Rubble piles with different frictions, cohesions, morphologies, grain size distributions, and structures are investigated. We find a 2016 HO |$_3$| shaped granular asteroid would undergo tensile failure at higher strengths as opposed to shear failure in lower strengths, regardless of its shape and constituent grain size ratio. In the tensile failure regime, the critical tensile strength is proportional to the square of the spin rate, but surprisingly, is independent of the internal friction angle. Such relations indicate that the Maximum Tensile Stress criterion emerges as superior paradigm for investigating the failure behaviour of fast-rotating asteroids. We predict that the high-spin rate of asteroid 2016 HO |$_3$| requires a surface strength over |$\sim$| 3 Pa and a bulk tensile strength over |$\sim$| 10–30 Pa. Through comparing these strength conditions with the latest data from asteroid missions, we suggest a higher likelihood of a monolithic structure over a typical rubble pile structure. However, the possibility of the latter cannot be completely ruled out. In addition, the asteroid's surface could retain a loose regolith layer globally or only near its poles, which could be the target for sampling of Tianwen-2 mission. [ABSTRACT FROM AUTHOR]

The temporary capture (TC) of Jupiter-family objects has long been a pivotal focus in celestial mechanics research. This study investigates the TC of objects near Jupiter within the context of the planar circular restricted three-body problem (PCRTBP), employing Lagrangian coherent structures (LCSs) and periapsis Poincaré maps. Initially, LCSs are identified via periapsis Poincaré maps and applied to segment the phase space. Parameter scanning enables a detailed analysis, classifying the orbital behaviours of objects in the proximity of Jupiter into three distinct categories: TC, low-energy flyby, and collision, each designating specific regions in phase space. Subsequently, a novel method for screening potential TC objects within the Jupiter system is proposed and validated, informed by the dynamic characteristics of TC motions. The efficacy of this method is illustrated by the re-identification of six known TC comets and the prediction of a prospective TC asteroid, 2002 GV28. Within the framework of the PCRTBP, analogous TC trajectories for these comets and asteroids are identified, offering novel insights into the dynamics of TC events. [ABSTRACT FROM AUTHOR]

Asteroids pose significant threats to Earth, necessitating early detection for potential deflection. Leveraging machine learning (ML), we classify asteroids into near-Earth Asteroids (particularly Atens, Amors, Apollos, and Apoheles) and non-near-Earth asteroids, further categorizing them based on hazard potential. Training the seven models on a comprehensive data set of 4687 asteroids, we achieve high accuracy in prediction. The predictive capability of these models is critical for informed decision-making in planetary defense strategies. We apply different regularization techniques to prevent overfitting and validate the models using a large unseen data set. A rigorous long-term N -body integration spanning 1 Myr is executed utilizing the Mercury N -body integrator to illuminate the evolution of asteroid properties over extended temporal scales. Following this integration process, the best-performing ML model is employed to classify asteroids based on their orbital characteristics and hazardous status respectively. Our findings highlight the effectiveness of ML in asteroid classification and prediction, paving the way for large-scale applications. By dividing a 1 Myr integration into intervals, we uncover temporal trends in asteroid behaviour, revealing insights into hazard evolution and ejection patterns. Notably, initially, hazardous asteroids tend to transition to non-hazardous states over time, elucidating key dynamics in planetary defense. We illustrate these findings through plotted graphs, providing valuable insights into asteroid dynamics. These insights are instrumental in advancing our understanding of long-term asteroid behaviour, with significant implications for future research and planetary protection efforts. [ABSTRACT FROM AUTHOR]

In an attempt to further characterize the near-Earth asteroid (NEA) population, we present 38 new light curves acquired between 2020 September and 2023 November for NEAs (7335) 1989 JA, (7822) 1991 CS, (154244) 2002 KL6, and (159402) 1999 AP10, obtained from observations taken at the Teide Observatory (Tenerife, Spain). With these new observations along with archival data, we computed their first shape models and spin solutions by applying the light-curve inversion method. The obtained rotation periods are in good agreement with those reported in previous works, with improved uncertainties. Additionally, besides the constant period models for (7335) 1989 JA, (7822) 1991 CS, and (159402) 1999 AP10, our results for (154244) 2002 KL6 suggest that it could be affected by a Yarkovsky–O'Keefe–Radzievskii–Paddack acceleration with a value of |$\upsilon \simeq -7\times 10^{-9}$| rad d |$^{-2}$|⁠. This would be one of the first detections of this effect slowing down an asteroid. [ABSTRACT FROM AUTHOR]

Particle–particle and particle–gas processes significantly impact planetary precursors such as dust aggregates and planetesimals. We investigate gas permeability (⁠|$\kappa$|⁠) in 12 granular samples, mimicking planetesimal dust regoliths. Using parabolic flights, this study assesses how gravitational compression – and lack thereof – influences gas permeation, impacting the equilibrium state of low-gravity objects. Transitioning between micro- and hyper-gravity induces granular sedimentation dynamics, revealing collective dust–grain aerodynamics. Our experiments measure |$\kappa$| across Knudsen number (Kn) ranges, reflecting transitional flow. Using mass and momentum conservation, we derive |$\kappa$| and calculate pressure gradients within the granular matrix. Key findings: (i) As confinement pressure increases with gravitational load and mass flow, |$\kappa$| and average pore space decrease. This implies that a planetesimal's unique dust-compaction history limits subsurface volatile outflows. (ii) The derived pressure gradient enables tensile strength determination for asteroid regolith simulants with cohesion. This offers a unique approach to studying dust-layer properties when suspended in confinement pressures comparable to the equilibrium state on planetesimals surfaces, which will be valuable for modelling their collisional evolution. (iii) We observe a dynamical flow symmetry breaking when granular material moves against the pressure gradient. This occurs even at low Reynolds numbers, suggesting that Stokes numbers for drifting dust aggregates near the Stokes–Epstein transition require a drag force modification based on permeability. [ABSTRACT FROM AUTHOR]

We have studied the evolution of near-Earth asteroid (NEA) families and pairs to inform future searches. To do so, we integrated clusters of simulated NEAs with different initial conditions, namely the orbital inclination, ejection speed, and the effects of mean-motion resonances on the parent body prior to breakup while also varying the orbit, mass, and number of perturbing planetary bodies. We studied the orbital element dispersion rates of NEA family members and found a power-law increase in those families whose orbits brought them close to a planet. This allowed us to conclude that family dispersion is significantly affected by the Kozai–Lidov effect due to oscillations in the eccentricity, and that the rate of dispersion is slowest at high inclination relatively far from the nearest planet. In most cases, the ejection speed of the initial breakup does not affect the dispersion, except within weaker mean-motion resonances where more violent breakups will result in the ejection of a fraction of the asteroids, causing a large increase in dispersion. Within mean-motion resonances, where Kozai–Lidov oscillations are slowed, increases in the dispersion of a family are delayed, leading them to be identifiable for longer. [ABSTRACT FROM AUTHOR]

While the data analysis of γ-ray telescopes has now become more robust, some signals may be misinterpretations of a time-variable foreground emission from the Solar system, induced by low-energy cosmic-ray interactions with asteroids. Our goal is to provide emission templates for this time-variable diffuse γ-ray foreground by considering the populations of Main Belt Asteroids, Jovian and Neptunian Trojans, Kuiper Belt Objects, and the Oort Cloud. We model the spatial distribution of all known asteroids by performing 3D-fits to determine their density profiles and calculate their appearances by line-of-sight integrations. Because Earth and the asteroids are moving with respect to each other, we obtain diffuse emission templates varying on time-scales of days to decades. We find that the temporal variability can lead to flux enhancements that may mimic emission features unless properly taken into account. This variation is further enhanced by the Solar cycle as the cosmic-ray spectrum is attenuated by the Solar modulation potential, leading to a relative flux increase of the outer asteroids. The cumulative effect of the time-dependent emission is illustrated for the case of the '511 keV OSSE fountain', and for emission features near the Galactic Centre, both being possible misinterpretations of the Solar system albedo. We recommend that γ-ray data analyses should always take into account the possibility of a time-variable foreground. Due to the ecliptic overlap with the Galactic plane, the Galactic emission is expected to be weaker by 0.1–20 per cent, depending on time (relative planetary motion), energy, and Solar cycle, which has consequences for the interpretation of dark matter annihilation cross sections, cosmic-ray spectra and amplitudes, as well as nucleosynthesis yields and related parameters. [ABSTRACT FROM AUTHOR]

White dwarf atmospheres are frequently polluted by material from their own planetary systems. Absorption features from Ca, Mg, Fe, and other elements can provide unique insights into the provenance of this exoplanetary material, with their relative abundances being used to infer accretion of material with core- or mantle-like composition. Across the population of white dwarfs, the distribution of compositions reveals the prevalence of geological and collisional processing across exoplanetary systems. By predicting the distribution of compositions in three evolutionary scenarios, this work assesses whether they can explain current observations. We consider evolution in an asteroid belt analogue, in which collisions between planetary bodies that formed an iron core lead to core- or mantle-rich fragments. We also consider layer-by-layer accretion of individual bodies, such that the apparent composition of atmospheric pollution changes during the accretion of a single body. Finally, we consider that compositional spread is due to random noise. We find that the distribution of Ca, Fe, and Mg in a sample of 202 cool DZs is consistent with the random noise scenario, although 7 individual systems show strong evidence of core-mantle differentiation from additional elements and/or low noise levels. Future surveys that detect multiple elements in each of a few hundred white dwarfs, with well-understood biases, have the potential to confidently distinguish between the three models. [ABSTRACT FROM AUTHOR]

The Japanese probe Hayabusa 2 recently visited the NEA (162173) Ryugu. This mission provided valuable information about the asteroid, including in situ images and a surface sample brought back to the Earth. The data suggests that Ryugu has likely been affected by space weathering, but the underlying cause of the surface modification remains unclear. This paper aims to shed light on the problem by providing new information about the possible past orbital path of Ryugu. We used a procedure to estimate how Ryugu has dynamically evolved since it entered the NEAs' region and whether this can explain the observed data. We have conducted numerical integrations of the N -body gravitational problem. The system comprises the Sun, the Solar system's eight planets, and a group of 29 000 test particles initially placed in the main asteroidal belt (MAB) near the ν6 secular resonance. We then tracked the particles that left the MAB and eventually arrived close to Ryugu's current orbit. Our analysis showed that out of 307 clones of Ryugu, only three came very close to the Sun at a distance of less than 0.1 au. Consequently, it is unlikely that Ryugu has undergone significant surface temperature variations. We also computed that ∼70 per cent of the clones have spent more than 5 Myr at an equivalent distance of 1 au from the Sun. This result suggests that Ryugu has been exposed to significant amounts of solar radiation over a long period, which may have resulted in space weathering effects on its surface. [ABSTRACT FROM AUTHOR]

This paper attempts to present a comprehensive analysis of the photopolarimetric properties of asteroids. In light of the limitations identified in several previously employed empirical formulae, this paper introduces a new formula that offers a reliable fit for the phase-polarization curve of asteroids. The validity of the new empirical formula is confirmed by analysing polarimetric data for lunar soil samples across a wide range of phase angles and various spectral bands. Notably, this investigation reveals a strong negative correlation between |$P_{\mathrm{ max}}$| and wavelength (⁠|$\lambda$|⁠) for lunar soil samples. Furthermore, the examination of key features of the phase-polarization curve of asteroids, such as the polarization minimum (⁠|$P_{\mathrm{ min}}$|⁠), polarization maximum (⁠|$P_{\mathrm{ max}}$|⁠), and the slope (h) at the inversion angle, allows us to explore their correlations with the geometric albedo (A) of asteroids. We have investigated whether our photopolarimetric studies could corroborate the existing classification scheme for asteroids, which divides them into three major composition classes: Chondrite (C), Metallic (M), and Stony (S)-types, based on spectral analysis. Our findings have revealed a good agreement with the existing classification. Each class is characterized by a specific combination of geometric albedo (A) and polarimetric properties (⁠|$P_{\mathrm{ min}}$|⁠ , |$P_{\mathrm{ max}}$|⁠ , and h) observed in asteroids, represented by four distinct regions. Interestingly, besides the three main types (C-, M-, and S-), we have found an overlapping region containing both M- and S-type asteroids. [ABSTRACT FROM AUTHOR]

We investigate the photometric properties of 35 well-observed asteroids using dense ground-based and sparse ATLAS survey data. Focusing on two-colour photometric phase functions, derived using inverse methods, we explore the wavelength dependence. Our study reveals distinct (G 1, G 2) domains for cyan and orange filters, especially among some S-complex asteroids. For other asteroids, substantial uncertainties prevail, or their distributions of phase curve parameters overlap, precluding definitive conclusions on wavelength dependence. Notably, for S-complex objects, the effect appears systematic, characterized by lower G 2 values in the cyan filter. The effect can be explained by considering the known geometric albedo correlation: higher albedo corresponds to flatter, whereas lower albedo corresponds to steeper phase curves. In the case of equal albedo, asteroids with red spectral slopes have a more pronounced opposition effect in red and asteroids with blue spectral slopes in blue filters. We explore the variation of slope differences of orange and cyan phase curves with phase angle. For most asteroids, the largest nominal variation is observed at phase angles < 10°. This suggests that the phase colouring for the orange–cyan colour slope is more pronounced at small phase angles. Through meticulous analysis of the opposition effect amplitudes, we also pinpoint preferred rotational pole solutions. We identify inconsistencies between phase curve parameters and spectral types in specific cases. The shape- and geometry-corrected phase curves signify an important advancement in studying asteroid photometric behaviour and may offer a deeper understanding of surface and regolith properties previously obscured by these effects, such as surface roughness. [ABSTRACT FROM AUTHOR]

Sparse and serendipitous asteroid photometry obtained by wide field surveys such as the Asteroid Terrestrial-impact Last Alert System (ATLAS) is a valuable resource for studying the properties of large numbers of small Solar System bodies. We have gathered a large data base of ATLAS photometry in wideband optical cyan and orange filters, consisting of 9.6 × 107 observations of 4.5 × 105 main belt asteroids and Jupiter Trojans. We conduct a phase curve analysis of these asteroids considering each apparition separately, allowing us to accurately reject outlying observations and to remove apparitions and asteroids not suitable for phase curve determination. We obtain a data set of absolute magnitudes and phase parameters for over 100 000 selected asteroids observed by ATLAS, |$\sim 66\, 000$| of which had sufficient measurements to derive colours in the ATLAS filters. To demonstrate the power of our data set we consider the properties of the Nysa–Polana complex, for which the ATLAS colours and phase parameters trace the S-like and C-like compositions amongst family members. We also compare the properties of the leading and trailing groups of Jupiter Trojans, finding no significant differences in their phase parameters or colours as measured by ATLAS, supporting the consensus that these groups were captured from a common source population during planetary migration. Furthermore, we identify ∼9000 asteroids that exhibit large shifts in derived absolute magnitude between apparitions, indicating that these objects have both elongated shapes and spin axes with obliquity ∼90 degrees. [ABSTRACT FROM AUTHOR]

The potentially hazardous asteroid 99942 Apophis will have a very close approach to the Earth in 2029. The encounter on its own may provide measurements of Earth's effects on Apophis' surface and also contribute to the improvement of some physical characteristics of the asteroid. In a previous work, we assumed the existence of a hypothetical disc of particles around Apophis before the 2029 encounter, and identified the particles that would escape from the gravity domain of Apophis due to the Earth's gravitational perturbation during the close encounter. In the current work, we investigate the possibility of a meteor activity originating from this event. We study the orbital evolution of these particles computing the MOIDs of the particles with respect to the Earth for the following 200 yr. Our results are not favourable for a meteor activity on Earth. However, a meteoroid activity on the Moon might happen during the encircling period after 88 yr of the 2029 encounter. [ABSTRACT FROM AUTHOR]

Combining archival photometric observations from multiple large-area surveys spanning the past 17 years, we detect long-term variability in the light curves of ZTF J032833.52−121945.27 (ZTF J0328−1219), ZTF J092311.41+423634.16 (ZTF J0923+4236), and WD 1145+017, all known to exhibit transits from planetary debris. ZTF J0328−1219 showed an overall fading in brightness from 2011 through to 2015, with a maximum dimming of ≃0.3 mag, and still remains ≃0.1 mag fainter compared to 2006. We complement the analysis of the long-term behaviour of these systems with high-speed photometry. In the case of ZTF J0923+4236 and WD 1145+017, the time-series photometry exhibits vast variations in the level of transit activity, both in terms of numbers of transits, as well as their shapes and depths, and these variations correlate with the overall brightness of the systems. Inspecting the current known sample of white dwarfs with transiting debris, we estimate that similar photometric signatures may be detectable in one in a few hundred of all white dwarfs. Accounting for the highly aligned geometry required to detect transits, our estimates imply that a substantial fraction of all white dwarfs exhibiting photospheric metal pollution from accreted debris host close-in planetesimals that are currently undergoing disintegration. [ABSTRACT FROM AUTHOR]

The minimal sizes of impactors that produced asteroid families were calculated, and their maximal sizes, i.e. the size that corresponds to head-on collisions, were estimated. We used data for 16 large families and the physical parameters of some members of these families available in NASA's JPL updated in 2022. We found that the typical minimal sizes of family-forming impactors were of the order of one-tenth the size of the parent bodies (PBs). The Themis family, for which the ratio of the radii r imp/ R PB = 0.08 and the mass loss is as large as 0.55, presents an example. The families of Juno and Euphrosyne, with the impactor to PB size ratio of an order of 0.01, are rather exceptional. The PBs of Juno and Euphrosyne families lost only 0.0014 and 0.0061 of their mass, respectively. It was found that the double structure of the Vesta family could have originated from two impacts by the bodies with radii as small as about 4 km, at least. [ABSTRACT FROM AUTHOR]

For fast-rotating asteroids, observed light curves could be very different from real light curves due to long exposure time. We present an improved observed light-curve model that accounts for long exposure time often encountered in observations of fast-rotating asteroids. By integrating brightness over time, we derive a more accurate observed light-curve model, allowing for better shape and spin state inversion results. Our analysis demonstrates that the fast-rotating model is more suitable for spin state inversion with longer exposure time, while the Kaasalainen model suffices for shorter exposure time. For spin state and shape inversion, exposure times of approximately 0.4 P and 0.2 P represent critical thresholds, respectively, beyond which the fast-rotating model exhibits superior performance. Notably, scattering parameters have minimal impact on the shape inversion results. These findings contribute valuable insights to the determination of shape and spin states for fast-rotating asteroids, shedding light on the challenges posed by long exposure time in such investigations. [ABSTRACT FROM AUTHOR]

This work presents novel findings that broaden our understanding of the amount of water that can be transported to the Earth. The key innovation lies in the combined usage of smoothed particle hydrodynamics (SPH) and N -body codes to assess the role of collision fragments in water delivery. We also present a method for generating initial conditions that enables the projectile to impact at the designated location on the target's surface with the specified velocity. The primary objective of this study is to simulate giant collisions between two Ceres-sized bodies by SPH near the ν6 secular resonance and follow the evolution of the ejected debris by numerical N -body code. With our method 6 different initial conditions for the collision were determined, and the corresponding impacts were simulated by SPH. Examining the orbital evolution of the debris ejected after collisions, we measured the amount of water delivered to the Earth, which is broadly 0.001 ocean equivalents of water, except in one case where one large body transported 7 per cent oceans of water to the planet. Based on this and taking into account the frequency of collisions, the amount of delivered water varies between 1.2 and 8.3 ocean's worth of water, depending on the primordial disc mass. According to our results, the prevailing external pollution model effectively accounts for the assumed water content on the Earth, whether it's estimated at 1 or 10 ocean's worth of water. [ABSTRACT FROM AUTHOR]

This work deals with a possible ultraviolet and infrared luminescence of the solid substance of the near-Earth objects. In particular, features of the phenomena of photoluminescence and cathodoluminescence of substance of these objects are considered. It is shown that ultraviolet and infrared luminescence of these objects can be revealed by orbital-based instruments. It is demonstrated that detectability of luminescence of near-Earth objects opens up the possibilities for determination of the physical–chemical properties of their solid substance and finding of the dark small low-albedo bodies, which could approach dangerously closer to the Earth. Equations for calculation of luminescence intensity of these objects are proposed. Data on the luminescence of the corresponding minerals and the numerical values of the yields of luminescence and albedo, as the conditions for the detectability of the luminescence of near-Earth objects are presented as well. [ABSTRACT FROM AUTHOR]

Objective: In the framework of the Cometary Physics Laboratory (CoPhyLab) and its sublimation experiments of cometary surface analogues under simulated space conditions, we characterize the properties of intimate mixtures of juniper charcoal and SiO2 chosen as a dust analogue (Lethuillier et al. 2022). We present the details of these investigations for the spectrophotometric properties of the samples. Methods: We measured these properties using a hyperspectral imager and a radio-goniometer. From the samples' spectra, we evaluated reflectance ratios and spectral slopes. From the measured phase curves, we inverted a photometric model for all samples. Complementary characterizations were obtained using a pycnometer, a scanning electron microscope and an organic elemental analyser. Results: We report the first values for the apparent porosity, elemental composition, and VIS-NIR spectrophotometric properties for juniper charcoal, as well as for intimate mixtures of this charcoal with the SiO2. We find that the juniper charcoal drives the spectrophotometric properties of the intimate mixtures and that its strong absorbance is consistent with its elemental composition. We find that SiO2 particles form large and compact agglomerates in every mixture imaged with the electron microscope, and its spectrophotometric properties are affected by such features and their particle-size distribution. We compare our results to the current literature on comets and other small Solar system bodies and find that most of the characterized properties of the dust analogue are comparable to some extent with the spacecraft-visited cometary nuclei, as well as to Centaurs, Trojans, and the bluest TNOs. [ABSTRACT FROM AUTHOR]

We apply the Hierarchical Clustering method (HCM) and Selective Backward Integration method (BIM) to search for associated families and young families for all main-belt active asteroids (MBAAs) known to date. We find four newly candidate sub-groups of known families, which include the candidate Brueghel family associated with 176P/LINEAR, the candidate 324P group associated with 324P/La Sagra, the candidate G1 group associated with P/2016 G1, and the candidate Tutenchamun family associated with (62412) 2000 SY178. Additionally, we identify three entirely new candidate families, the Interamnia family associated with P/2021 A5, the candidate 457P group associated with 457P/Lemmon-PANSTARRS, and the candidate Scheila family associated with (596) Scheila. We also reveal two newly identified family associations with known families between 259P/Garradd and the Adeona family, P/2019 A4 and the Jones family. All main-belt comets (MBCs) are likely associated with young and primitive families. Some unstable MBCs, which cannot be identified using HCM, may still originate from young and primitive families. However, due to dynamic diffusion, they cannot be conclusively linked to current families. Impact-disrupted asteroids could be linked with young families and they may change their original spectrum under the impact activity. Rotational fission of young and primitive asteroids might be a useful mechanism for facilitating the exposure of subsurface ice, and therefore triggering sublimation-driven activity. Rapid rotation and sublimation activity mechanisms are likely coupled. Therefore, further research should be made on such fast rotational asteroids that are located in primitive families. [ABSTRACT FROM AUTHOR]

The impact of the Double Asteroid Redirection Test (DART) spacecraft with Dimorphos allows us to study asteroid collision physics, including momentum transfer, the ejecta properties, and the visibility of such events in the Solar system. We report observations of the DART impact in the ultraviolet (UV), visible light, and near-infrared (IR) wavelengths. The observations support the existence of at least two separate components of the ejecta: a fast and a slow component. The fast-ejecta component is composed of a gaseous phase, moving at about 1.6 km s−1 with a mass of ≲104 kg. The fast ejecta is detected in the UV and visible light, but not in the near-IR z -band observations. Fitting a simplified optical thickness model to these observations allows us to constrain some of the properties of the fast ejecta, including its scattering efficiency and the opacity of the gas. The slow ejecta component is moving at typical velocities of up to about 10 m s−1. It is composed of micrometer-size particles, that have a scattering efficiency, at the direction of the observer, of the order of 10−3 and a total mass of ∼106 kg. The larger particles in the slow ejecta, whose size is bound to be in the range between ∼1 mm and ∼1 m, likely have a scattering efficiency larger than that of the pre-impact Didymos system. [ABSTRACT FROM AUTHOR]

We analyse the role of the general relativity (GR) on the nodal librations of test particles located at the Habitable Zone (HZ) around a solar-mass star, which evolve under the influence of an eccentric planetary-mass perturber with a semimajor axis of 0.1 au. Based on a secular Hamiltonian up to quadrupole level, we derive analytical criteria that define the nodal libration region of an HZ particle as a function of its eccentricity e 2 and inclination i 2, and the mass m 1 and the eccentricity e 1 of the perturber. We show that an HZ particle can experience nodal librations with orbital flips or purely retrograde orbits for any m 1 and e 1 by adopting a suitable combination of e 2 and i 2. For m 1 < 0.84 MJup, the greater the m 1 value, the smaller the e 2 value above which nodal librations are possible for a given e 1. For m 1 > 0.84 MJup, an HZ test particle can undergo nodal librations for any e 2 and appropriate values of e 1 and i 2. The same correlation between m 1 and e 2 is obtained for nodal librations with orbital flips, but a mass limit for m 1 of 1.68 MJup is required in this case. Moreover, the more massive the inner perturber, the greater the nodal libration region associated with orbital flips in the (e 1, i 2) plane for a given value of e 2. Finally, we find good agreements between the analytical criteria and results from N -body simulations for values of m 1 ranging from Saturn-like planets to super-Jupiters. [ABSTRACT FROM AUTHOR]

We present 24 new dense light curves of the near-Earth asteroids (3103) Eger, (161989) Cacus, (2100) Ra-Shalom, and (12711) Tukmit, obtained with the Instituto Astrofísico Canarias 80 and Telescopio Abierto Remoto 2 telescopes at the Teide Observatory (Tenerife, Spain) during 2021 and 2022, in the framework of projects visible NEAs observations survey and NEO Rapid Observation, Characterization and Key Simulations. The shape models and rotation state parameters (P , λ, β) were computed by applying the light curve inversion method to the new data altogether with the archival data. For (3013) Eger and (161989) Cacus, our shape models and rotation state parameters agree with previous works, though they have smaller uncertainties. For (2100) Ra-Shalom, our results also agree with previous studies. Still, we find that a Yarkovsky–O'Keefe–Radzievskii–Paddack acceleration of υ = (0.223 ± 0.237) × 10−8 rad d−2 slightly improves the fit of the light curves, suggesting that (2100) Ra-Shalom could be affected by this acceleration. We also present for the first time a shape model for (12711) Tukmit, along with its rotation state parameters (P  = 3.484900 ± 0.000031 h, λ = 27° ± 8°, β = 9° ± 15°). [ABSTRACT FROM AUTHOR]

While proper orbital elements are currently available for more than 1 million asteroids, taxonomical information is still lagging behind. Surveys like SDSS-MOC4 provided preliminary information for more than 100 000 objects, but many asteroids still lack even a basic taxonomy. In this study, we use Dark Energy Survey (DES) data to provide new information on asteroid physical properties. By cross-correlating the new DES data base with other data bases, we investigate how asteroid taxonomy is reflected in DES data. While the resolution of DES data is not sufficient to distinguish between different asteroid taxonomies within the complexes, except for V-type objects, it can provide information on whether an asteroid belongs to the C- or S-complex. Here, machine learning methods optimized through the use of genetic algorithms were used to predict the labels of more than 68 000 asteroids with no prior taxonomic information. Using a high-quality, limited set of asteroids with data on gri slopes and i − z colours, we detected 409 new possible V-type asteroids. Their orbital distribution is highly consistent with that of other known V-type objects. [ABSTRACT FROM AUTHOR]

The Centaur (60558) Echeclus was discovered on 2000 March 03, orbiting between the orbits of Jupiter and Uranus. After exhibiting frequent outbursts, it also received a comet designation, 174P. If the ejected material can be a source of debris to form additional structures, studying the surroundings of an active body like Echeclus can provide clues about the formation scenarios of rings, jets, or dusty shells around small bodies. Stellar occultation is a handy technique for this kind of investigation, as it can, from Earth-based observations, detect small structures with low opacity around these objects. Stellar occultation by Echeclus was predicted and observed in 2019, 2020, and 2021. We obtain upper detection limits of rings with widths larger than 0.5 km and optical depth of τ = 0.02. These values are smaller than those of Chariklo's main ring; in other words, a Chariklo-like ring would have been detected. The occultation observed in 2020 provided two positive chords used to derive the triaxial dimensions of Echeclus based on a 3D model and pole orientation available in the literature. We obtained a  = 37.0 ± 0.6 km, b  = 28.4 ± 0.5 km, and c  = 24.9 ± 0.4 km, resulting in an area-equivalent radius of 30.0 ± 0.5 km. Using the projected limb at the occultation epoch and the available absolute magnitude (⁠|$\rm {H}_{\rm {v}} = 9.971 \pm 0.031$|⁠), we calculate an albedo of p v = 0.050 ± 0.003. Constraints on the object's density and internal friction are also proposed. [ABSTRACT FROM AUTHOR]

The rotational properties of ∼10-m-scale asteroids are poorly understood with only a few measurements. Additionally, collisions or thermal recoil can spin their rotations to periods less than a few seconds obfuscating their study due to the observational cadence imposed by the long read-out times of charge-coupled device imagers. We present a method to measure the rotation periods of 10-m-scale asteroids using the target of opportunity capability of the Canada–France–Hawaii Telescope (CFHT) and its MegaCam imager by intentionally streaking their detections in single exposures when they are at their brightest. Periodic changes in brightness as small as ∼0.05 mag along the streak can be measured as short as a few seconds. Additionally, the streak photometry is taken in multiple g, r , and i filter exposures enabling the measurement of asteroid colours. The streak photometry method was tested on CFHT observations of three 10-m-scale asteroids, 2016 GE1, 2016 CG18, and 2016 EV84. Our three targets are among the smallest known asteroids with measured rotation periods/colours having some of the shortest known rotation periods. We compare our rotation period and taxonomic results with independent data from the literature and discuss applications of the method to future small asteroid observations. [ABSTRACT FROM AUTHOR]

In this paper, we perform a dynamical study of the population of objects in the unstable quasi-Hilda region. The aim of this work is to make an update of the population of quasi-Hilda comets (QHCs) that have recently arrived from the Centaurs region. To achieve our goal, we have applied a dynamical criteria to constrain the unstable quasi-Hilda region that allowed us to select 828 potential candidates. The orbital data of the potential candidates were taken from the ASTORB data base and we apply backward integration to search by those that have recently arrived from the outer regions of the Solar system. Then we studied the dynamical evolution of the candidates from a statistical point of view by calculating the time-averaged distribution of a number of clones of each candidate as a function of aphelion and perihelion distances. We found that 47 objects could have been recently injected into the inner Solar system from the Centaur or transneptunian regions. These objects may have preserved volatile material and are candidates to exhibit cometary activity. [ABSTRACT FROM AUTHOR]

Small Solar system bodies serve as pristine records that have been minimally altered since their formation. Their observations provide valuable information regarding the formation and evolution of our Solar system. Interstellar objects can also provide insight on the formation of exoplanetary systems and planetary system evolution as a whole. In this work, we present the application of our framework to search for small Solar system bodies in exoplanet transit survey data collected by the Antarctic Search for Transiting ExoPlanets (ASTEP) project. We analysed data collected during the Austral winter of 2021 by the ASTEP 400 telescope located at the Concordia Station, at Dome C, Antarctica. We identified 20 known objects from dynamical classes ranging from Inner Main-belt asteroids to one comet. Our search recovered known objects down to a magnitude of V  = 20.4 mag, with a retrieval rate of ∼80 per cent for objects with V ≤ 20 mag. Future work will apply the pipeline to archival ASTEP data that observed fields for periods of longer than a few hours to treat them as deep-drilling data sets and reach fainter limiting magnitudes for slow-moving objects, on the order of V ≈ 23–24 mag. [ABSTRACT FROM AUTHOR]

The study of near-Earth objects (NEOs) allow us to obtain information on the Solar system smallest bodies due to their closeness to Earth. In this work, we present the results of visible spectroscopic observations of 43 small and newly discovered NEOs, obtained during eighteen observing runs between October 2020 and December 2021, using the Goodman High Throughput Spectrograph at the 4.1-m Southern Astrophysical Research telescope (Cerro Pachón, Chile). We found a taxonomic distribution dominated by S-type asteroids but with an overabundance of A- and D-types. This result is in agreement with recent works on NEOs' characterization and has implications for possible differences in the taxonomic distribution of 'large' and 'small' objects and emphasizes the idea of a non-homogeneous NEO population. [ABSTRACT FROM AUTHOR]

We present a physical model and spin-state analysis of the potentially hazardous asteroid (23187) 2000 PN9. As part of a long-term campaign to make direct detections of the Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effect, we collected optical light curves of the asteroid between 2006 and 2020. These observations were combined with planetary radar data to develop a detailed shape model, which was used to search for YORP acceleration. We report that 2000 PN9 is a relatively large top-shaped body with a sidereal rotation period of 2.53216 ± 0.00015 h. Although we find no evidence for rotational acceleration, YORP torques smaller than |$\sim 10^{-8}\, \rm rad\,{d}^{-2}$| cannot be ruled out. It is likely that 2000 PN9 is a YORP-evolved object, and may be an example of YORP equilibrium or self-limitation. [ABSTRACT FROM AUTHOR]

Meteorites provide an important source of information about the formation and composition of asteroids, because the level of accuracy of studies and analyses performed in a laboratory cannot be achieved by any ground- or space-based observation. To better understand what asteroid types a meteorite represents, it is crucial to identify the body they originated from. In this paper, we aim to determine possible parent bodies for the known meteorite falls among the known population of near-Earth asteroids (NEAs). By using the similarity criterion DN , based on geocentric quantities, we found 20 possible NEA–meteorite pairs. By performing additional numerical simulations of the backward dynamics, we found that 12 of these pairs may be associated with a possible separation event from the progenitor NEA, while the remaining 8 pairs appear to be ambiguous or random associations. The most interesting are the Pribram and Neuschwanstein meteorites, which are dynamically associated with (482488) 2012 SW20 with a common separation age dating back to about 20–30 kyr ago, and the Motopi Pan meteorite, which has three candidate parent bodies: (454100) 2013 BO73, 2017 MC3, and 2009 FZ4. The average time of separation between our meteorite list and the progenitor body appears to be about 10 kyr, a time consistent with what is expected from the collision frequency of small NEAs. Based on our results, we suggest that about 25 per cent of meteorites do not originate in the main belt, but mainly from little collision events happening between NEAs in the inner Solar system. [ABSTRACT FROM AUTHOR]

We study nodal librations of outer particles in the framework of the elliptical restricted three-body problem including general relativity (GR) effects. From an analytical treatment based on secular interactions up to quadrupole level, we derive equations that define the nodal libration region of an outer test particle, which depends on the physical and orbital parameters of the bodies of the system. From this, we analyse how the GR constrains the semimajor axis of outer test particles that experience nodal librations under the effects of an inner planet around a single stellar component. Such an upper limit of the semimajor axis, which is called a 2,lim, depends on the mass of the star m s, the mass m 1, the semimajor axis a 1, and the eccentricity e 1 of the inner planet, and the eccentricity e 2 of the outer test particle. On the one hand, our results show that the greater m 1, a 1, and e 2 and the smaller m s, the greater the value of a 2,lim. On the other hand, for fixed m s, m 1, a 1, and e 2, a 2,lim does not strongly depend on e 1, except for large values of such an orbital parameter. We remark that N -body experiments of particular scenarios that include GR show results consistent with the analytical criteria derived in this research. Moreover, the study of hypothetical small body populations of real systems composed of a single star and an inner planetary-mass companion show that the GR effects can play a very important role in their global dynamics. [ABSTRACT FROM AUTHOR]

Recent observations and detections of interstellar objects (ISOs) passing through the Solar system have sparked a wave of interest into these objects. Although rare, these ISOs can be captured into bound orbits around the Sun. In this study, we investigate the novel idea of capture of ISOs into near-Earth orbits and find that a steady population of ISOs exists among the current population of near-Earth objects (NEOs). Using numerical simulations, we find that the capture of ISOs into near-Earth orbits is dominated by Jupiter that is 104 times more efficient in capturing ISOs compared to Earth. Captured ISOs are more likely to be in orbits with high eccentricities and low inclinations. We also investigate the stability of captured ISOs and find that they are generally unstable and have an average survival lifetime of ∼1 Myr, consistent with lifetime of NEOs originating from outer asteroid belt, and are ejected from the Solar system due to interactions with other planets or the Sun. Our results have important implications for understanding the population of ISOs in the Solar system and possible future detection. We find that about one to a few 50–70 m sized captured ISOs among NEOs would be detectable by Vera Rubin Observatory over its lifetime. By detecting and studying captured ISOs, we can learn about the properties and origins of such objects, and the formation and evolution of exoplanetary systems and even our Solar system. [ABSTRACT FROM AUTHOR]

Dynamic exploration around non-spherical bodies has increased in recent decades due to the interest in studying the motion of spacecraft orbits, moons, and particle ring around these bodies. The dynamic structure around these objects is defined by regular and chaotic regions. The Poincaré surface of section technique allows mapping these regions, identifying the location of resonances, and the size of regular and chaotic zones, thus helping us to understand the dynamics around these bodies. Using this technique, we map in the a – e space the stable and unstable regions around ellipsoidal bodies, such as the dwarf planet Haumea, the centaur Chariklo, and other five hypothetical bodies, in which we keep part of the physical parameters of Haumea but we varied its period of rotation and ellipticity, to analyse the impact of these alterations in the extensions of the stable and unstable regions due to first kind orbits and spin-orbit type resonances. We identified a large region of stability, in semimajor axis and eccentricity, due to the first kind orbits. Periodic orbits of the first kind are present in a large semimajor axis interval for all considered systems and have almost zero eccentricity, while resonant and quasi-periodic orbits have high eccentricities. Furthermore, we identified the bifurcation of the 2:6 resonance when there is a spin reduction of a body with the same physical parameters as Haumea. This bifurcation generates a chaotic region, reducing the extension of the stability zone. [ABSTRACT FROM AUTHOR]

The dynamical interaction of minor bodies (such as comets or asteroids) with planets plays an essential role in the planetary system's architecture and evolution. As a result of these interactions, structures such as the Kuiper belt and the Oort cloud can be created. In particular, the collision of minor bodies with planets can drastically change the planet's internal and orbital evolution. We present an analytical formulation to determine the collision time-scale for a minor body to impact a planet for arbitrary geometry. By comparing with a suite of detailed N -body simulations and an analytical method for collision time-scales in the Solar system, we confirmed the accuracy of our analytical formulation. As a proof of concept, we focused on the collision time-scales of minor bodies similar to the Jupiter-family comets and the long-period comets with a Jupiter-like planet. We show that our analytical method yields in good agreement with the numerical simulations. The formalism presented here thus provides a succinct and accurate alternative to numerical calculations. [ABSTRACT FROM AUTHOR]

This study presents the analysis of forced photometry data in the o and c filters of centaurs 29P/Schwassmann–Wachmann and (2060) Chiron obtained by the ATLAS network between 2015 and 2022. Centaur 29P had 24 outbursts with a median peak brightness of −3.0 and a range of −3.7 mag, regardless of spectral band. Some of these outbursts exhibited an asymmetric light curve with respect to peak brightness, with brightness decreases ranging from −0.22 to −7.6 mag h−1 and durations from 2.8 min to 1.4 d. The slope m of the photometric profile of the coma after/before and during an outburst was ≤1 and >1, respectively, reflecting an increase in brightness at the optocenter of the object. Without the outbursts, 29P has an absolute magnitudes H0 of 9.3 ± 0.2 and 9.10 ± 0.01 in the c and o filters, respectively, and activity indices of n = 11.56 ± 0.08 and 2.1 ± 0.1. Using the Lomb–Scargle periodogram, a periodicity of 0.97 d was found in the c magnitudes after perihelion, probably related to nuclear rotation. The absolute magnitude of Chiron in the HG1G2 system in the o filter is nearly constant between 2017 and 2020, with a weighted mean of 5.35 ± 0.03. In 2021, the brightness increases to H = 4.54 ± 0.03 and decreases to 5.04 ± 0.04 in 2022. This increase in 2021 is not due to outbursts that did not occur during the entire observing campaign, but is related to the increase in opposition effect. [ABSTRACT FROM AUTHOR]

The observation of Near Earth objects (NEOs) allows us to study the physical properties of the smallest size bodies of our Solar System and help impose constraints on their origin and evolution. The solar phase curve is a very important tool to derive diverse physical properties of a small body so that we set up an observational campaign to derive the phase curve parameters (H, G 1, G 2) for a large number of NEOs. We present here the obtained phase curves for 12 NEOs, along with the rotation period for two of them and the V–R colour for four. The data was acquired mainly at the Astronomical Observatory of Sertão de Itaparica (Brazil), with some NEOs also observed at the Osservatorio di Campo Imperatore (Italy). Considering all the objects observed throughout our campaign we analysed a homogeneous dataset of 30 NEOs along with data acquired by ATLAS (Asteroid Terrestrial-impact Last Alert System telescopes survey) for MB asteroids. The behavior in the phase space G 1- G 2 of 21,865 MBA and 103 NEOs was analysed, separating the objects in intervals of albedos and sizes. From the large MB data set we found evidence that the distribution in the G 1- G 2 phase space has strong dependence not only on the albedo but also on the object's size. This is particularly true for the smaller objects. The main result being that, on the contrary to what occurs with the MB larger objects, we are unable to estimate the albedo of a NEO from its phase curve parameters. [ABSTRACT FROM AUTHOR]

The aim of this work is to verify the stability of the proposed orbital solutions for the third moonlet (Delta) taking into account a realistic gravitational potential for the central body of the quadruple system (Alpha). We also aim to estimate the location and size of a stability region inside the orbit of Gamma. First, we created a set of test particles with intervals of semimajor axis, eccentricities, and inclinations that covers the region interior to the orbit of Gamma, including the proposed orbit of Delta and a wide region around it. We considered three different models for the gravitational potential of Alpha: irregular polyhedron, ellipsoidal body, and oblate body. For a second scenario, Delta was considered a massive spherical body and Alpha an irregular polyhedron. Beta and Gamma were assumed as spherical massive bodies in both scenarios. The simulations showed that a large region of space is almost fully stable only when Alpha was modelled simply as an oblate body. For the scenario with Delta as a massive body, the results did not change from those as mass-less particles. Beta and Gamma do not play any relevant role in the dynamics of particles interior to the orbit of Gamma. Delta's predicted orbital elements are fully unstable and far from the nearest stable region. The primary instability source is Alpha's elongated shape. Therefore, in the determination of the orbital elements of Delta, it must be taken into account the gravitational potential of Alpha assuming, at least, an ellipsoidal shape. [ABSTRACT FROM AUTHOR]

Tidal disruption events are common in the Universe, which may occur in various compact star systems and could account for many astrophysical phenomena. Depending on the separation between the central compact star and its companion, either a full disruption or a partial disruption may occur. The partial disruption of a rocky planet around a neutron star (NS) can produce kilometer-sized clumps, but the main portion of the planet can survive. The dynamical evolution of these clumps is still poorly understood. In this study, the characteristics of partial disruption of a rocky planet in a highly elliptical orbit around a NS is investigated. The periastron of the planet is assumed to be very close to the NS so that it would be partially disrupted by tidal force every time it passes through the periastron. It is found that the fragments generated in the process will change their orbits on a time scale of a few orbital periods due to the combined influence of the NS and the remnant planet, and will finally collide with the central NS. Possible outcomes of the collisions are discussed. [ABSTRACT FROM AUTHOR]

Small Solar system bodies have widely dispersed orbital poles, posing challenges to dynamical models of Solar system origin and evolution. To characterize the orbit pole distribution of dynamical groups of small bodies it helps to have a functional form for a model of the distribution function. Previous studies have used the small-inclination approximation and adopted variations of the normal distribution to model orbital inclination dispersions. Because the orbital pole is a directional variable, its distribution can be more appropriately modelled with directional statistics. We describe the von Mises–Fisher (vMF) distribution on the surface of the unit sphere for application to small bodies' orbital poles. We apply it to the orbit pole distribution of the observed Plutinos. We find a mean pole located at inclination i 0 = 3.57° and longitude of ascending node Ω0 = 124.38° (in the J2000 reference frame), with a 99.7 per cent confidence cone of half-angle 1.68°. We also estimate a debiased mean pole located 4.6° away, at i 0 = 2.26°, Ω0 = 292.69°, of similar-size confidence cone. The vMF concentration parameter of Plutino inclinations (relative to either mean pole estimate) is κ = 31.6. This resembles a Rayleigh distribution function, with width parameter σ = 10.2°. Unlike previous models, the vMF model naturally accommodates all physical inclinations (and no others), whereas Rayleigh or Gaussian models must be truncated to the physical inclination range 0–180°. Further work is needed to produce a theory for the mean pole of the Plutinos against which to compare the observational results. [ABSTRACT FROM AUTHOR]

The Active Asteroids (AAs), are a small population of minor planets with characteristics similar to both asteroids and comets. In the search for the AAs, the analysis of light curves promises to be an efficient approach to identify candidates. In an effort towards an automatable method to detect AA candidates (AAc) through light curve analysis, in this work, we present a comprehensive comparison of the methodologies used for the reduction of the photometric data in previous works against other variations proposed here. We analyse the impact of different phase models in the reduction of the data and in the analysis of light curves. As a proof of concept, we studied a random sample of 1000 asteroids from the IAU's Minor Planet Center (MPC) Observation Database. The aim is to both test the methodology and search for AAc among them. The constraints imposed on the sample were that more than 150 photometric observations spanning all bands and a perihelion distance of q < 2.7 au are required for each object. We find that it is preferred, for the purpose of decreasing the possibility of false-positive detections, to reduce and analyse the photometric data from different bands independently, rather than doing it jointly with a one-size-fits-all correction, as done in previous works. We found strong indicators of activity in the light curves of five asteroids: (2776) Baikal, (11456) Cotto-Figueroa, (12528), (66944), and (71907). Other two asteroids, numbered (12871) and (329604), show signs of activity, but the indicators are not as strong. [ABSTRACT FROM AUTHOR]

The ephemerides of minor planets are computed on the basis of astrometric observations. The asteroid orbit determination process requires these observations to be properly weighted to take into account the expected accuracy of the data. If not directly provided by the observers, the weights are, in general, computed after a station-specific statistical analysis on the observation residuals, where the influence of external factors such as epoch of observation, magnitude, and employed catalogue has been proven. In this paper, we perform a statistical analysis on observation residuals of the major surveys taking into account a new factor, i.e. the dynamical classification of asteroids, to understand whether the observation quality may have a dependence on the different type of observed object. If an influence is actually found, then it will be possible to develop a new weighting system based on these results. The weights will be easily applicable once one knows the asteroid orbit. In particular, four stations have been found having different qualities depending on whether they are observing near-Earth asteroids or main-belt asteroids. Moreover, the cross-correlation between the dynamic classification and epoch, magnitude, and catalogue is investigated, as well as the influence of these factors on observations' quality. [ABSTRACT FROM AUTHOR]

All near-Earth asteroids (NEAs) that reach sufficiently small perihelion distances will undergo a so-called super-catastrophic disruption. The mechanisms causing such disruptions are currently unknown or, at least, undetermined. To help guide theoretical and experimental work to understand the disruption mechanism, we use numerical simulations of a synthetic NEA population to identify the resonant mechanisms that are responsible for driving NEAs close to the Sun, determine how these different mechanisms relate to their dynamical lifetimes at small heliocentric distances and calculate the average time they spend at different heliocentric distances. Typically, resonances between NEAs and the terrestrial and giant planets are able to dramatically reduce the perihelion distances of the former. We developed an algorithm that scans the orbital evolution of asteroids and automatically identifies occurrences of mean motion and secular resonances. We find that most near-Sun asteroids are pushed to small perihelion distances by the 3:1J and 4:1J mean-motion resonances with Jupiter, as well as the secular resonances ν6, ν5, ν3, and ν4. The time-scale of the small-perihelion evolution is fastest for the 4:1J, followed by the 3:1J, whereas ν5 is the slowest. Approximately 7 per cent of the test asteroids were not trapped in a resonance during the latest stages of their dynamical evolution, which suggests that the secular oscillation of the eccentricity due to the Kozai mechanism, a planetary close encounter, or a resonance that we have not identified pushed them below the estimated average disruption distance. [ABSTRACT FROM AUTHOR]

Small Solar system bodies are pristine remnants of Solar system formation, which provide valuable insights for planetary science and astronomy. Their discovery and cataloguing also have strong practical implications to life on Earth as the nearest asteroids could pose a serious impact threat. Concurrently with dedicated observational projects, searches for small bodies have been performed on numerous archival data sets from different facilities. Here, we present a framework to increase the scientific return of an exoplanet transit-search survey by recovering serendipitous detections of small bodies in its daily and archival data using a GPU-based synthetic tracking algorithm. As a proof of concept, we analysed |$12\, \times 12\, \mathrm{arcmin^2}$| sky fields observed by the 1-m telescopes of the SPECULOOS survey. We analysed 90 sky fields distributed uniformly across the sky as part of the daily search for small bodies and 21 archival fields located within 5 deg from the ecliptic plane as part of the archival search (4.4 deg2 in total). Overall, we identified 400 known objects of different dynamical classes from Inner Main-belt Asteroids to Jupiter Trojans and 43 potentially new small bodies with no priors on their motion. We were able to reach limiting magnitude for unknown objects of V = 23.8 mag, and a retrieval rate of ∼80 per cent for objects with V < 22 mag and V < 23.5 mag for the daily and archival searches, respectively. SPECULOOS and similar exoplanet surveys can thus serve as pencil-beam surveys for small bodies and probe parameter space beyond V = 22 mag. [ABSTRACT FROM AUTHOR]

In the framework of the visible NEAs observations survey (ViNOS) that uses several telescopes at the Canary Islands observatories since 2018, we observed two superfast rotator NEAs, 2021 NY1 and 2022 AB. We obtained photometry and spectrophotometry of both targets and visible spectroscopy of 2022 AB. Light curves of 2021 NY1 obtained in four different nights between 2021 September 30 and 2021 October 16 return a rotation period P  = 13.3449 ± 0.0013 minutes and a light curve amplitude A  = 1.00 mag. We found that 2021 NY1 is a very elongated superfast rotator with an axis ratio a / b ≥ 3.6. We also report colours (g − r) = 0.664 ± 0.013, (r − i) = 0.186 ± 0.013, and (i − zs) = −0.117 ± 0.012 mag. These are compatible with an S-type asteroid. The light curves of 2022 AB obtained on 2021 January 5 and 2021 January 8 show a rotation period P  = 3.0304 ± 0.0008 min, with amplitudes A  = 0.52 and A  = 0.54 mag. 2022 AB is also an elongated object with axis ratio a / b ≥ 1.6. The obtained colours are (g − r) = 0.400 ± 0.017, (r − i) = 0.133 ± 0.017, and (i − zs) = 0.093 ± 0.016. These colours are similar to those of the X-types, but with an unusually high (g − r) value. Spectra obtained on 2022 January 12 and 2022 January 14 are consistent with the reported colours. The spectral upturn over the 0.4 - 0.6 |$\mu \mathrm{m}$| region of 2022 AB does not fit with any known asteroid taxonomical class or meteorite spectrum, confirming its unusual surface properties. [ABSTRACT FROM AUTHOR]

We numerically investigate tidally induced surface refreshing on Apophis during its close approach with Earth within a perigee distance of 5.96 Earth radii on 2029 April 13. We implement a tidal resurfacing model with two stages: dynamics modelling of the entire body to determine time-varying accelerations and surface slope profiles felt by each surface patch during the 6-h-long closest encounter, and discrete-element method modelling to track motions of surface grains in localized patches. The surface slope profiles and measured grain motions are combined to statistically extrapolate the 'expected' percentage of resurfaced area. Using the tidal resurfacing model, we present surface maps showing the total expected resurfacing on Apophis given three representative encounter orientations. Our simulation results indicate that tidal resurfacing, limited to certain localized regions, will likely occur half an hour before perigee and on the scale of 1 per cent of Apophis's entire surface area. Our models indicate that the most likely locations to detect tidal resurfacing are: initially high-sloped regions (>30°) regardless of the encounter orientation of Apophis, and mid-sloped regions (15°–30°) that experience a significant positive slope variation (>0.5°), which is mainly controlled by the encounter orientation. Expected data from ground-based observations of the 2029 flyby will help us better constrain the targeted locations likely to experience tidal resurfacing. We thus expect to find evidence supporting tidal resurfacing via further analysis of post-encounter surface images or albedo changes at the expected resurfaced areas. [ABSTRACT FROM AUTHOR]

Knowledge of the interior density distribution of an asteroid can reveal its composition and constrain its evolutionary history. However, most asteroid observational techniques are not sensitive to interior properties. We investigate the interior constraints accessible through monitoring variations in angular velocity during a close encounter. We derive the equations of motion for a rigid asteroid's orientation and angular velocity to arbitrary order and use them to generate synthetic angular velocity data for a representative asteroid on a close Earth encounter. We develop a toolkit AIME (Asteroid Interior Mapping from Encounters) which reconstructs asteroid density distribution from these data, and we perform injection-retrieval tests on these synthetic data to assess AIME's accuracy and precision. We also perform a sensitivity analysis to asteroid parameters (e.g. asteroid shape and orbital elements), observational setup (e.g. measurement precision and cadence), and the mapping models used. We find that high precision in rotational period estimates (≲0.27 s) is necessary for each cadence, and that low perigees (≲ 18 Earth radii) are necessary to resolve large-scale density non-uniformities with uncertainties of |$\sim 0.1{{\ \rm per\ cent}}$| of the local density under some models. [ABSTRACT FROM AUTHOR]

We present new results of the observing program which is a part of the NEOROCKS project aimed to improve knowledge on physical properties of near-Earth Objects (NEOs) for planetary defense. Photometric observations were performed using the 1.2-m telescope at the Haute-Provence observatory (France) in the BVRI filters of the Johnson–Cousins photometric systems between June 2021 and April 2022. We obtained new surface colours for 42 NEOs. Based on the measured colours, we classified 20 objects as S-complex, nine as C-complex, nine as X-complex, two as D-type, one object as V-type, and one object remained unclassified. For all the observed objects, we estimated their absolute magnitudes and diameters. Combining these new observations with the previously acquired data within the NEOROCKS project extended our data set to 93 objects. The majority of objects in the data set with diameters D < 500 m belongs to a group of silicate bodies, which could be related to observational bias. Based on MOID and Δ V values we selected 14 objects that could be accessible by a spacecraft. Notably, we find D-type asteroid (163014) 2001 UA5 and A-type asteroid 2017 SE19 to be of particular interest as possible space mission targets. [ABSTRACT FROM AUTHOR]

Many potential mechanisms for delivering planetary debris to within a few Roche radii of white dwarfs rely on gravitational scattering events that feature perturbers which are giant planets or terrestrial planets. However, the population of these planets orbiting white dwarfs is still unknown, and for a substantial fraction of white dwarfs the largest planetary survivors of stellar evolution may be sub-terrestrial mass minor planets. Here, we attempt to identify the smallest mass perturbers that could pollute white dwarfs. Through computationally expensive numerical simulations of both unstable and stable configurations of minor planets, we find that this critical lower bound equals approximately one Luna mass (1 M ☾ ≈ 10-1 M ♂ ≈ 10-2 M ⊕ ≈ 102 M Ceres). Further, we find that as this mass limit is approached from above, the typical cooling age at which white dwarf pollution occurs increases. Consequently, there is a two order-of-magnitude range of perturber masses between Earth and its moon that has remained largely unexplored in white dwarf pollution studies, despite the potential formation of thousands of such Luna-sized objects in these systems. [ABSTRACT FROM AUTHOR]