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Aims.We present spectroscopic results for nine M-type asteroids (325 Heidelberga, 497 Iva, 558 Carmen, 687 Tinette, 766 Moguntia, 860 Ursina, 909 Ulla, 1280 Baillauda, and 1564 Srbija) in the 0.8-2.5 μm spectral region. One visible spectrum is also presented for the asteroid 497 Iva. These asteroids were observed during several runs between 2003 and 2007, and the main goal was to investigate the NIR spectral region of M-type asteroids.

Aims.The mineralogy of the asteroid (2867) Steins was investigated in the framework of a ground-based science campaign dedicated to the future encounter with Rosetta spacecraft.

Aims.In the framework of the ground-based science campaign dedicated to the encounter with the Rosetta spacecraft, the mineralogy of the asteroid (21) Lutetia was investigated.

Aims.The Karin cluster is a small asteroid family that formed $5.8 \pm 0.2$Myr ago in the outer main belt. This is an exceptionally young age for an asteroid family. To investigate the composition and homogeneity of the members of this family, we started a spectroscopic survey in the visible and in the near-IR.

We obtained high signal to noise spectra of the two targets of the Dawn mission, 4 Vesta and 1 Ceres from observations carried out in remote control between the Observatoire de Paris-Meudon and the NASA Infrared Telescope Facility on Mauna Kea. 4 Vesta was observed in the 0.7–2.5 $\mu{\rm m}$spectral region at three different rotational phases in order to i) determine the mineral composition; ii) understand the spectral variations across the surface. Vesta was also observed in the 2.0–3.8 $\mu{\rm m}$range. The 3 μm absorption feature was not detected, implying the absence of OH and/or H2O-bearing minerals on the asteroid surface at the latitude of our observations. The spectrum of 1 Ceres was obtained in the 2.0–4.1 μm range and the presence of the 3.06 μm absorption feature confirmed. Laboratory measurement of ion-irradiated organics and ices suggest that the 3.06 μm feature can be reproduced with a linear mixture of crystalyne ice and residues of ion-irradiated asphaltite.

The new Rosetta mission baseline to the comet 67P/Churyumov-Gerasimenko includes two asteroid fly-bys. To help in target selection we studied all the candidates of all the possible scenarios. Observations have been carried out at ESO-NTT (La Silla, Chile), TNG (Canaries), and NASA-IRTF (Hawaii) telescopes, in order to determine the taxonomy of all the candidates. The asteroid targets were chosen after the spacecraft interplanetary orbit insertion manoeuvre, when the available total amount of $\Delta V$was known. On the basis of our analysis and the available of $\Delta V$, we recommended to the ESA Science Working Group the asteroids 21 Lutetia and 2867 Steins as targets for the Rosetta mission. The nature of Lutetia is still controversial. Lutetia's spectral properties may be consistent with a composition similar to carbonaceous chondrite meteorites. The spectral properties of Steins suggest a more extensive thermal history. Steins may have a composition similar to relatively rare enstatite chondrite/achondrite meteorites.

A physical portrait based on spectral and photometric data of 4979 Otawara, the first asteroid target of the Rosetta mission, is presented. The aim of this work is to investigate the composition of 4979 Otawara and to evaluate its rotation pole orientation. The spectroscopic observations obtained at the Palomar 200´´and IRTF telescopes cover the wavelength range 0.4 to 2.5 µm, and provide a definitive classification of Otawara as an S-type asteroid. An analysis of band depths and slopes places Otawara in the S(IV) subgroup, suggesting a similarity to ordinary chondrite meteorites. Moreover we present new photometric data, obtained at the Asiago Observatory and at the TNG telescope, that allow confirmation of the fast rotational period of $2.707\pm 0.005$hours, and a first indication of the spin vector of Otawara.?

Asteroid 9969 Braille (1992 KD) was encountered on July 29, 1999 by the Deep Space 1 mission, the first of NASA's New Millennium Program, launched on October 24 1998. The data obtained by the space mission seem to indicate a composition of the object similar to that of Vesta. To complete the information obtained in the infrared region by the Deep Space 1 mission we have performed a visible spectroscopic and photometric investigation of the asteroid respectively with the 1.5 m telescope and the NTT of ESO, La Silla. The spectrum was obtained in the spectral range 4500-8200 Å and, for the photometry, BVRIfilters were used. In this paper we report the results of the analysis of the data obtained indicating that, on the basis of our visible data, the composition of the asteroid may range from V-type to Q-type, but we observe also a strong similarity to the H-type ordinary chondrites.

We report the results of the first statistical analysis of colours ($B-V$, $V-R$, $V-I$, and $V-J$) of the Trans-Neptunian and Centaur populations. Using the same statistical techniques applied to define the current asteroid taxonomy, we find a continuous spread of the objects between neutral colour to very red. Pushing further the analysis, the TNOs may be split into four groups. The differences in colour content are interpreted as a consequence of the TNOs evolution (i.e. collisional history, space weathering, ...)

The Canada‐France‐Hawaii Legacy Survey (CFHTLS) comprising about 25 000 MegaCam images was data mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 143 asteroids (109 NEAs and 34 PHAs) were found on 508 candidate images which were field corrected and measured carefully, and their astrometry was reported to Minor Planet Centre. Both recoveries and precoveries (apparitions before discovery) were reported, including data for 27 precovered asteroids (20 NEAs and 7 PHAs) and 116 recovered asteroids (89 NEAs and 27 PHAs). Our data prolonged arcs for 41 orbits at first or last opposition, refined 35 orbits by fitting data taken at one new opposition, recovered 6 NEAs at their second opposition and allowed us to ameliorate most orbits and their Minimal Orbital Intersection Distance (MOID), an important parameter to monitor for potential Earth impact hazard in the future (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids NEAs, Potentially Hazardous Asteroids PHAs and Virtual Impactors VIs. These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other asteroids appearing occasionally in their fields. This data mining could be eased using a server to search and classify findings based on the asteroid class and the discovery date as “precoveries” or “recoveries”. We built PRECOVERY, a public facility which uses the Virtual Observatory SkyBoT webservice of IMCCE to search for all known Solar System objects in a given observation. To datamine an entire archive, PRECOVERY requires the observing log in a standard format and outputs a database listing the sorted encounters of NEAs, PHAs, numbered and unnumbered asteroids classified as precoveries or recoveries based on the daily updated IAU MPC database. As a first application, we considered an archive including about 13 000 photographic plates exposed between 1930 and 2005 at the Astronomical Observatory in Bucharest, Romania. Firstly, we updated the database, homogenizing dates and pointings to a common format using the JD dating system and J2000 epoch. All the asteroids observed in planned mode were recovered, proving the accuracy of PRECOVERY. Despite the large field of the plates imaging mostly 2.27° × 2.27° fields, no NEA or PHA could be encountered occasionally in the archive due to the small aperture of the 0.38m refractor insufficiently to detect objects fainter than V∼ 15. PRECOVERY can be applied to other archives, being intended as a public facility offered to the community by the EURONEAR project. This is the first of a series of papers aimed to improve orbits of PHAs and NEAs using precovered data derived from archives of images to be data mined in collaboration with students and amateurs. In the next paper we will search the CFHT Legacy Survey, while data mining of other archives is planned for the near future © 2009 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim

Observations of the predicted occultation between the satellites Miranda and Oberon were performed on 2007 July 30. Data analysis reveals that the predicted magnitude drop for this phenomenon was overestimated and we establish an upper limit of 0m. 05 for the phenomenon, perhaps due to a nonlambertian limb scattering. The new astrometry obtained from this run is in good agreement with the LA06 numerical model and these new data will improve the dynamical models of the Uranus system. The paper concludes with an uncertainty analysis on the parameters for the event, determined by the uncertainty of the magnitude drop of about 0.04 mag, and the difficulty to observe mutual phenomena between satellites in the Uranian system. © 2008 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim

Aims.Investigation of the physical nature of the asteroid 21?Lutetia, target of Rosetta mission, is required for the completion of its ground-based science and in the frame of its future fly-by. Monitoring this object is essential in preparing the future encounter with the spacecraft.Methods.The asteroid was observed with SpeX/IRTF in the spectral region 0.9-4.0??m, in remote observing mode from Meudon, in March 2003 and August 2004. Results.The new spectrum in the range 0.9-2.5??m confirms the previous results (Birlan et al. 2004), for a neutral trend with a large shallow band around 1??m. The spectral region around 3??m is usually considered as a tracer of aqueous alteration of the surface. The 3??m band in Lutetias' spectrum is shallower than those of hydrated asteroids, and the 2.9 vs. 3.2 ratio reveals a value close to the CV-CO meteorites. The band around 3.1??m, if it exists in the spectrum of 21?Lutetia, is different from the one present in the spectrum of 1?Ceres, and is lower than 0.5%.

The principal component (PC) and G-mode multivariate statisticshave been used in analysing the set of the 34 Edgeworth–Kuiper objects (EKOs) – 23 Trans NeptunianObjects (TNO) and 11 Centaurs – for which B, V, R, I, J homogeneous photometry were available.The results obtained show that V-I and V-Js are the key parameters in structuring the sample inhomogeneous groups. The PC1 axis (which contains ∼93% of the sample total variance) spans fivetimes more than the PC2 (which contains ∼6% of the sample total variance). The extremesof the PC1 axis contain the objects having a flat spectrum (low PC1 values) and a very red spectrumrespectively. Independently, the G-mode analysis allows us to distinguish six homogeneous groups of objectswhich confirm and extend the results obtained with the PC analysis. In addition to these groups, a few objectsremain not included in any group (i.e., does not have significant similitude with other objects) and yet givean indication of a more complex compositional structure of the sample. These preliminary results will haveto be confirmed and completed when a larger sample is available, but they provide some interesting hintsfor understanding the – mainly collisional – evolution of the EKOs.

Remote observations between Paris Observatory and Mauna Kea (Hawaii) have been started two years ago. Nowadays ten runs have been already conducted from the remote observing center located in Meudon. The main topics of our investigations were devoted to physical studies of minor planets (Binzel et al. 2004, Birlan et al. 2004) and to spectral investigations of planetary atmospheres. Our experience attained its maturity and the acquired feed-backs allow us to discern between the advantages and difficulties of this observing technique. The main purpose of this paper is to share the remote observing experience and to valorize it in the frame of robotic telescope concept. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Context.Near-Earth objects are among the most accessible bodies in the solar system in terms of the spacecraft propulsion requirements to reach them. The choice of targets and the planning of space missions are based on high quality ground-based science.

Context. The EUROpean Near Earth Asteroid Research (EURONEAR) is a network which envisions to bring some European contributions into the general context traced by the Spaceguard Foundation which was carried out during the last 15 years mainly by the US with some modest European and amateur contributions. Aims. The number of known near Earth asteroids (NEAs) and potentially hazardous asteroids (PHAs) has increased tremendously, mainly thanks to five major surveys all focused on the discovery of new bodies. But also other facilities are required to follow-up and improvement the orbital parameters and to study the physical properties of the known bodies. These goals are better achieved by a co-ordinated network such as EURONEAR. Methods. Astrometry is mandatory in order to acquire the positional information necessary to define and improve orbits of NEAs and PHAs and to study their trajectories through the solar system, especially in the vicinity of Earth. Photometry is required to derive some physical information about NEAs and PHAs. In order to achieve these objectives, the main method of research of the EURONEAR is the follow-up programme of objects selected by a few criteria, carried out mostly at 1 m-class telescopes endowed with medium and large field cameras. Results. 162 NEAs summing more than 1500 individual positions were observed for a total time of 55 nights in both visiting mode and regular runs using nine telescopes located in four countries. The observations were reduced promptly and reported to the Minor Planet Centre (MPC) which validated and included them in the MPC and NEODyS databases following the improvement of their orbital elements. For one binary NEA we acquired photometry and were able to determine its orbital and rotational periods. Complementary to the follow-up work, as many as 500 unknown moving objects consistent with new Main Belt asteroids and one possible NEA were discovered in the analyzed fields. Conclusions. Our positions present 1$\arcsec$precision with an accuracy of 0.2–0.4$\arcsec$, sufficient for achieving our immediate main goals. The observations and data reduction were conducted by our network members, which included some students and amateurs supervised by professional astronomers. In most cases, we increased the observational arcs decreasing the uncertainties in the orbits, while in some cases the new positions allowed us to recover some bodies endangered to be lost, defining their orbits.

Context. The EUROpean Near Earth Asteroid Research (EURONEAR) is a network which envisions to bring some European contributions into the general context traced by the Spaceguard Foundation which was carried out during the last 15 years mainly by the US with some modest European and amateur contributions.

Aims. We investigate the link between the International Celestial Reference Frame (ICRF) and the dynamical reference frame realized by the ephemerides of the Solar System bodies. Methods. We propose a procedure that implies a selection of events for asteroids with accurately determined orbits crossing the CCD field containing selected quasars. Using a Bulirsch-Stoer numerical integrator, we constructed 8-years (2010–2018) ephemerides for a set of 836 numbered near-Earth asteroids (NEAs). We searched for close encounters (within a typical field of view of ground-based telescopes) between our selected set of asteroids and quasars with high-accuracy astrometric positions extracted from the Large Quasars Astrometric Catalog (LQAC).Results. In the designated period (2010–2018), we found a number of 2924, 14?257, and 6972 close approaches (within 10$\arcmin$) between asteroids with a minimum solar elongation value of 60°and quasars from the ICRF-Ext2, the Very Large Baseline Array Calibrator Survey (VLBA-CS), and the Very Large Array (VLA), respectively. This large number of close encounters provides the observational basis needed to investigate the link between the dynamical reference frame and the ICRF.

Aims. We investigate the link between the International Celestial Reference Frame (ICRF) and the dynamical reference frame realized by the ephemerides of the Solar System bodies. Methods. We propose a procedure that implies a selection of events for asteroids with accurately determined orbits crossing the CCD field containing selected quasars. Using a Bulirsch-Stoer numerical integrator, we constructed 8-years (2010–2018) ephemerides for a set of 836 numbered near-Earth asteroids (NEAs). We searched for close encounters (within a typical field of view of ground-based telescopes) between our selected set of asteroids and quasars with high-accuracy astrometric positions extracted from the Large Quasars Astrometric Catalog (LQAC).Results. In the designated period (2010–2018), we found a number of 2924, 14?257, and 6972 close approaches (within 10$\arcmin$) between asteroids with a minimum solar elongation value of 60°and quasars from the ICRF-Ext2, the Very Large Baseline Array Calibrator Survey (VLBA-CS), and the Very Large Array (VLA), respectively. This large number of close encounters provides the observational basis needed to investigate the link between the dynamical reference frame and the ICRF.

Aims. We investigate the link between the International Celestial Reference Frame (ICRF) and the dynamical reference frame realized by the ephemerides of the Solar System bodies.