Search

An observational study of Koronis family members' spin properties was undertaken with two primary objectives: to reduce selection biases for object rotation period and lightcurve amplitude in the sample of members' known spin vectors, and to better constrain future modeling of spin properties evolution. Here we report rotation lightcurves of nineteen Koronis family members, and derived results that increase the sample of determined spin vectors in the Koronis family to include 34 of the largest 36 family members, completing it to $H \approx 11.3$ ($D \sim 16$ km) for the largest 32 members. The program observations were made during a total of 72 apparitions between 2005-2021, and are reported here along with several earlier unpublished lightcurves. All of the reported data were analyzed together with previously published lightcurves to determine the objects' sidereal rotation periods, spin vector orientations, and convex model shape solutions. The derived distributions of retrograde rotation rates and pole obliquities appear to be qualitatively consistent with outcomes of modification by thermal YORP torques. The distribution of spin rates for the prograde rotators remains narrower than that for the retrograde rotators; in particular, the absence of prograde rotators having periods longer than about 20 h is real, while among the retrograde rotators are several objects having longer periods up to about 65 h. None of the prograde objects newly added to the sample appear to be trapped in an $s_6$ spin-orbit resonance that is characteristic of most of the largest prograde objects; these smaller objects either could have been trapped previously and have already evolved out, or have experienced spin evolution tracks that did not include the resonance., 49 pages, 29 figures, accepted for publication in Icarus

Lightcurves for 5 asteroids were obtained from the Center for Solar System Studies from 2015 October to December.

CCD photometric observations of seven asteroids were obtained from the Center for Solar System Studies from 2016 April to June.

CCD photometry observations made in 2015 October and November of the Vestoid asteroid 5425 Vojtech showed it to be binary. The primary lightcurve has a period of 2.64759 ± 0.000004 h and an amplitude 0.27 ± 0.02 mag. The orbital period of the satellite is 25.43 ± 0.02 h. Based on mutual events ranging from 0.05 to 0.09 mag, the estimated effective diameter ratio of the two bodies is Ds/Dp ≥ 0.22 ± 0.02.

CCD photometric observations of two Hungaria asteroids were obtained from the Center for Solar System Studies from 2017 January to March.

Lightcurves for 18 Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2017 January to March.

Lightcurves for six Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2016 October to December.

CCD photometric observations of 10 main-belt asteroids were obtained from the Center for Solar System Studies from 2018 July to September.

Lightcurves for 45 Near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2018 July-September were analyzed for rotation period and signs of satellites or tumbling. NEA 13553 Massakikoyama appears to be in non-principal axis rotation, i.e., tumbling. 2011 UA (D = 0.6 km) is a super-fast rotator with a period of 0.316391 ± 0.000007 h. The period and size place it well above the spin barrier. The period for 2018 RQ2 is multiply ambiguous, with possible solutions of 4.28 h or 5.17 h (monomdal lightcurve) and 8.58 h or 10.60 h (bimodal lightcurve). 2018 KE3 may be a binary asteroid.

Lightcurves for 32 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2018 September-December were analyzed for rotation period and signs of satellites or tumbling.

Lightcurves for four L(5) Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 January to March. The suspected binary Trojan, 2207 Antenor was observed again and a single attenuation event was detected.

CCD photometry observations made in 2016 October and November of the Hungaria asteroid (24465) 2000 SX155 showed it to be binary. The primary lightcurve has a period of 2.66087 ± 0.00005 h and an amplitude 0.08 ± 0.02 mag. The orbital period of the satellite is 9.252 ± 0.001 h, the shortest detected so far.

Lightcurves for 19 Hilda asteroids were obtained at the Center for Solar System Studies (CS3) from 2016 August through December.

Lightcurves for 16 Hilda asteroids were obtained at the Center for Solar System Studies (CS3) from 2016 June to September.

CCD photometric observations of 10 main-belt asteroids were obtained from the Center for Solar System Studies from 2019 January to March. In light of recent period analysis, images of 2120 Tyumenia obtained in 2004 were re-examined. The resulting analysis found a period of 17.515 h, which is consistent with the recent results.

CCD photometric observations of three Hilda asteroids were made at the Center for Solar System Studies (CS3) from 2019 January-March. For 1038 Tuckia, the period solution was ambiguous at either P = 18.020 h, amplitude 0.22 mag or P = 14.401 h, amplitude 0.20 mag. For 2246 Bowell, the analysis found P = 4.997 and amplitude 0.46 mag. For 4317 Garibaldi, we found a dual-period solution with P(1) = 17.843 or 8.92 h and P(2) = 11.426 h. The shorter value for P(1) is similar to previously reported results but this is the first time a true dual-period solution, i.e., not an ambiguous single period solution, has been reported.

CCD photometric observations of 25 main-belt asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 July to September.

CCD photometric observations of 18 main-belt asteroids were obtained from the Center for Solar System Studies from 2018 October to December. A pole solution was found for 4910 Kawasato of (λ, β, P(SID)) = (355°, 35°, 4.66271 h). (31320) 1998 HX2 is a binary asteroid with a P(1) of 2.8149 ± 0.0001 h and P(2) of 47.06 ± 0.05 h.

Lightcurves for 11 L(4) Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2019 July to September.

Lightcurves for 38 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2019 March-July were analyzed for rotation period, peak-to-peak amplitude, and signs of satellites or tumbling.

‘Mumbai North’ features black-and-white aerial photographs of the city’s suburban ecologies—social and natural. Spanning from Sanjay Gandhi National Park to Gorai Creek, and from Bhiwandi’s Waral Lake to Powai, the series visually engages with the ecosystems of Mumbai. Juxtaposed against each photograph are excerpts from archival publications, such as the 1964 Report on the Development Plan for Greater Bombay and the 1965 Marg publication, Bombay, Planning and Dreaming. Together, these two art forms are interwoven into a photo-literary tapestry spanning decades, providing historical insight as to how policies and development plans of the past have shaped urban forms of the present. Air pollution levels, as monitored by the Maharashtra Pollution Control Board, record the contents of atmospheric contaminants such as sulphur dioxide, nitrogen dioxide and respirable suspended particulate matter. This photo-essay integrates multiple layers of information—visual, historical and anthropogenic—as a contemporary means of a new civic survey.

Lightcurves for 24 near-Earth asteroids (NEAs) obtained at the Center for Solar System Studies (CS3) from 2019 January-April were analyzed for rotation period, peak-to-peak amplitude, and signs of satellites or tumbling. Two asteroids, (381677) 2009 BJ81 and (454177) 2013 GJ35, were found to have two periods that make them additional candidates for the class of very wide binary asteroids. Another object with two periods was (18736) 1998 NU, 2.4753 h and 11.95 h. The second period solution is weak but does not seem to be systematic in nature. Potential tumblers include (88254) 2001 FM129, (90403) 2003 YE45, and 2006 SK134.

The recent close approach of the NEA (3200) Phaethon offered a rare opportunity to obtain high-quality observational data. We used the newly obtained optical light curves to improve the spin and shape model of Phaethon and to determine its surface physical properties derived by thermophysical modeling. We also used the available astrometric observations of Phaethon, including those obtained by the Arecibo radar and the Gaia spacecraft, to constrain the secular drift of the orbital semimajor axis. This constraint allowed us to estimate the bulk density by assuming that the drift is dominated by the Yarkovsky effect. We used the convex inversion model to derive the 3D shape model of Phaethon, and a detailed numerical approach for an accurate analysis of the Yarkovsky effect. We obtained a unique solution for Phaethon's pole orientation at $(318,-47)^{\circ}$ ecliptic longitude and latitude (uncertainty of $5^{\circ}$), and confirm the previously reported thermophysical properties ($D=5.1\pm0.2$ km, $\Gamma=600\pm200$ SI). Phaethon has a top-like shape with possible north-south asymmetry. The characteristic size of the regolith grains is 1-2 cm. The orbit analysis reveals a secular drift of the semimajor axis of $-(6.9\pm1.9)\times 10^{-4}$ au Myr$^{-1}$. With the derived volume-equivalent size of 5.1~km, the bulk density $\rho$ is $1.67\pm0.47$ g cm$^{-3}$. If the size is slightly larger $\sim5.7$ km, as suggested by radar data, $\rho$ would decrease to $1.48\pm0.42$ g cm$^{-3}$. We further investigated the suggestion that Phaethon may be in a cluster with asteroids (155140) 2005 UD and (225416) 1999 YC that was formed by rotational fission of a critically spinning parent body. Phaethon's $\rho$ is consistent with typical values for large ($>100$ km) C-complex asteroids and supports its association with asteroid (2) Pallas. These findings render a cometary origin unlikely for Phaethon., Comment: Accepted for publication in A&A

Several lines of evidence support a common origin for, and possible hereditary link between, cometary nuclei and jovian Trojan asteroids. Due to their distance and low albedos, few comet-sized Trojans have been studied. We present new lightcurve information for 19 Trojans ≲ 30 km in diameter, more than doubling the number of objects in this size range for which some rotation information is known. The minimum densities for objects with complete lightcurves are estimated and are found to be comparable to those measured for cometary nuclei. A significant fraction (∼40%) of this observed small Trojan population rotates slowly ( P > 24 h), with measured periods as long as 375 h (Warner, B.D., Stephens, R.D. [2011]. Minor Planet Bull. 38, 110–111). The excess of slow rotators may be due to the YORP effect. Results of the Kolmogorov–Smirnov test suggest that the distribution of Trojan rotation rates is dissimilar to those of Main Belt Asteroids of the same size. Concerted observations of a large number of Trojans could establish the spin barrier (Warner, B.D., Harris, A.W., Pravec, P. [2009]. Icarus 202, 134–146), making it possible to estimate densities for objects near the critical period.

Using the S-band radar at Arecibo Observatory, we observed thirteen X/M-class asteroids; nine were previously undetected and four were re-observed, bringing the total number of Tholen X/M-class asteroids observed with radar to 29. Of these 29M-class asteroids, 13 are also W-class, defined as M-class objects that also display a 3-μm absorption feature which is often interpreted as the signature of hydrated minerals (Jones, T.D., Lebofsky, L.A., Lewis, J.S., Marley, M.S. [1990]. Icarus 88, 172–192; Rivkin, A.S., Howell, E.S., Britt, D.T., Lebofsky, L.A., Nolan, M.C., Branston, D.D. [1995]. Icarus 117, 90–100; Rivkin, A.S., Howell, E.S., Lebofsky, L.A., Clark, B.E., Britt, D.T. [2000]. Icarus 145, 351–368). Consistent with our previous work (Shepard, M.K. et al. [2008]. Icarus 195, 184–205; Shepard, M.K., Harris, A.W., Taylor, P.A., Clark, B.E., Ockert-Bell, M., Nolan, M.C., Howell, E.S., Magri, C., Giorgini, J.D., Benner, L.A.M. [2011]. Icarus 215, 547–551), we find that 38% of our sample (11 of 29) have radar albedos consistent with metal-dominated compositions. With the exception of 83 Beatrix and 572 Rebekka, the remaining objects have radar albedos significantly higher than the mean S- or C-class asteroid (Magri, C., Nolan, M.C., Ostro, S.J., Giorgini, J.D. [2007]. Icarus 186, 126–151). Seven of the eleven high-radar-albedo asteroids, or 64%, also display a 3-μm absorption feature (W-class) which is thought to be inconsistent with the formation of a metal dominated asteroid. We suggest that the hydration absorption could be a secondary feature caused by low-velocity collisions with hydrated asteroids, such as CI or CM analogs, and subsequent implantation of the hydrated minerals into the upper regolith. There is recent evidence for this process on Vesta (Reddy, V. et al. [2012]. Icarus 221, 544–559; McCord, T.B. et al. [2012]. Nature 491, 83–86; Prettyman, T.H. et al. [2012]. Science 338, 242–246; Denevi, B.W. et al. [2012]. Science 338, 246–249). Eleven members of our sample show bifurcated radar echoes at some rotation phases; eight of these are high radar albedo targets. One interpretation of a bifurcated echo is a contact binary, like 216 Kleopatra, and several of our sample are contact binary candidates. However, evidence for other targets indicates they are not contact binaries. Instead, we hypothesize that these asteroids may have large-scale variations in surface bulk density, i.e. isolated patches of metal-rich and silicate-rich regions at the near-surface, possibly the result of collisions between metal and silicate-rich asteroids.

The purpose of this study was to intercompare hydrocarbon (HC) measurements performed by a number of different instruments: a gas chromatograph (GC), a flame ionization detector (FID), a fourier transform infrared spectrometer (FTIR), a commercially produced non-dispersive infrared analyzer (NDIR), and two remote sensors. These instruments were used to measure total HC concentrations in a variety of samples, including (1) ten different individual HC species, (2) 12 different vehicle exhaust samples, and (3) three different volatilized fuel samples. The 12 exhaust samples were generated by operating two different vehicles on a dynamometer. Each vehicle was operated at different times with three different fuels. The vehicles were operated fuel rich, i.e., with low air/fuel ratios to encourage elevated exhaust HC levels. Some of the exhaust samples were obtained while operating each vehicle at a stoichiometric air/fuel ratio with one spark plug wire disconnected. To quantify the degree to which the various instruments agreed with the FID, a parameter called the response factor was used, where the response factor was defined as the HC/CO2 ratio measured by each instrument divided by the HC/CO2 ratio measured by the dynamometer bench. Of the various instruments, only the GC yielded response factors that were consistently at or close to one. The other instruments typically had values at or below one. For the ten individual HC species studied, the NDIR and remote sensors obtained response factors between 0.05 and 1.0, with the highest response factors being obtained for the alkanes and the lowest response factors obtained for toluene and ethylene. For the exhaust samples, the NDIR and remote sensors obtained response factors between 0.23 and 0.68. For raw fuel samples, the response factors were between 0.44 and 0.68. NDIR and remote sensor measurements correlated very poorly with total HC in exhaust.

Second-by-second modal emissions data from a 73-vehicle fleet of 1990 and 1991 light duty cars and trucks driven on the Federal Test Procedure (FTP) driving cycle were examined to determine remote sensing errors of commission in identifying high emissions vehicles. Results are combined with a similar analysis of errors of omission based on modal FTP data from high emissions vehicles. Extremely low errors of commission combined with modest errors of omission indicate that remote sensing should be very effective in isolating high CO and HC emitting vehicles in a fleet of late model vehicles on the road.

We collected data on rotations and elongations of 46 secondaries of binary and triple systems among near-Earth, Mars-crossing and small main belt asteroids. 24 were found or are strongly suspected to be synchronous (in 1:1 spin–orbit resonance), and the other 22, generally on more distant and/or eccentric orbits, were found or are suggested to have asynchronous rotations. For 18 of the synchronous secondaries, we constrained their librational angles, finding that their long axes pointed to within 20° of the primary on most epochs. The observed anti-correlation of secondary synchroneity with orbital eccentricity and the limited librational angles agree with the theories by Cuk and Nesvorný (Cuk, M., Nesvorný, D. [2010]. Icarus 207, 732–743) and Naidu and Margot (Naidu, S.P., Margot, J.-L. [2015]. Astron. J. 149, 80). A reason for the asynchronous secondaries being on wider orbits than synchronous ones may be longer tidal circularization time scales at larger semi-major axes. The asynchronous secondaries show relatively fast spins; their rotation periods are typically 10 h. An intriguing observation is a paucity of chaotic secondary rotations; with an exception of (35107) 1991 VH, the secondary rotations are single-periodic with no signs of chaotic rotation and their periods are constant on timescales from weeks to years. The secondary equatorial elongations show an upper limit of a 2 / b 2 ∼ 1.5 . The lack of synchronous secondaries with greater elongations appears consistent, considering uncertainties of the axis ratio estimates, with the theory by Cuk and Nesvorný that predicts large regions of chaotic rotation in the phase space for a 2 / b 2 ≳ 2 . Alternatively, secondaries may not form or stay very elongated in gravitational (tidal) field of the primary. It could be due to the secondary fission mechanism suggested by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D.J. [2011]. Icarus 214, 161–178), as its efficiency is correlated with the secondary elongation. Sharma (Sharma, I. [2014]. Icarus 229, 278–294) found that rubble-pile satellites with a 2 / b 2 ≲ 1.5 are more stable to finite structural perturbations than more elongated ones. It appears that more elongated secondaries, if they originally formed in spin fission of parent asteroid, are less likely to survive intact and they more frequently fail or fission.

Our photometric observations of 18 main-belt binary systems in more than one apparition revealed a strikingly high number of 15 having positively re-observed mutual events in the return apparitions. Our simulations of the survey showed that it cannot be due to an observational selection effect and that the data strongly suggest that poles of mutual orbits between components of binary asteroids in the primary size range 3–8 km are not distributed randomly: The null hypothesis of an isotropic distribution of the orbit poles is rejected at a confidence level greater than 99.99%. Binary orbit poles concentrate at high ecliptic latitudes, within 30° of the poles of the ecliptic. We propose that the binary orbit poles oriented preferentially up/down-right are due to either of the two processes: (i) the YORP tilt of spin axes of their parent bodies toward the asymptotic states near obliquities 0° and 180° (pre-formation mechanism) or (ii) the YORP tilt of spin axes of the primary components of already formed binary systems toward the asymptotic states near obliquities 0° and 180° (post-formation mechanism). The alternative process of elimination of binaries with poles closer to the ecliptic by dynamical instability, such as the Kozai effect due to gravitational perturbations from the Sun, does not explain the observed orbit pole concentration. This is because for close binary asteroid systems, the gravitational effects of primary’s irregular shape dominate the solar-tide effect.

We present the results of absolute photometry – the absolute brightness HV, the effective diameter, (B)VR color indices, composite light curves, period of rotation and amplitude of variations – of several small asteroids in the inner main-belt: 1344 Caubeta, 1401 Lavonne, 2947 Kippenhahn, 3913 Chemin, 3956 Caspar, 4375 Kiyomori, 4555 1987 QL, 5484 Inoda, 5985 1942 RJ, 6949 Zissell and main-belt asteroid 6867 Kuwano. The photometric observations of these objects were made in the period 2007–2009 as part of a project of photometric studies of small main-belt asteroids that involves a collaboration of a number of asteroid photometrists around the world.

Using the S-band radar at Arecibo Observatory, we observed six new M-class main-belt asteroids (MBAs), and re-observed one, bringing the total number of Tholen M-class asteroids observed with radar to 19. The mean radar albedo for all our targets is σ ˆ OC = 0.28 ± 0.13 , significantly higher than the mean radar albedo of every other class (Magri, C., Nolan, M.C., Ostro, S.J., Giorgini, J.D. [2007]. Icarus 186, 126–151). Seven of these objects (Asteroids 16 Psyche, 129 Antigone, 216 Kleopatra, 347 Pariana, 758 Mancunia, 779 Nina, 785 Zwetana) have radar albedos indicative of a very high metal content ( mean σ ˆ OC = 0.41 ± 0.13 ) , and consistent with a remnant iron/nickel core interpretation (irons) or exotic high metal meteorite types such as CB. We propose designating these high radar albedo objects as Mm. Two asteroids, 110 Lydia and 678 Fredegundis, have more moderate radar albedos ( mean σ ˆ OC = 0.22 ) , but exhibit high values ( σ ˆ OC ∼ 0.35 ) at some rotation phases suggesting a significant metal content. The remaining 10 objects have moderate radar albedos ( σ ˆ OC = 0.20 ± 0.06 ) at all rotation phases. Most of our targets have visible/near-infrared spectra (Hardersen, P.S., Gaffey, M.J., Abell, P.A. [2005]. Icarus 175, 141–158; Fornasier, S., Clark, B.E., Dotto, E., Migliorini, A., Ockert-Bell, M., Barucci, M.A. [2009]. Icarus, submitted for publication) that indicate the presence of at least some silicate phases. All of the non-Mm asteroids show a positive correlation between visual and radar albedo but the reasons for this are not clear. All of the higher radar albedo targets (the 7 Mm asteroids, Lydia, and Fredegundis) show moderate to large variations in radar albedo with rotation phase. We suggest that their high radar reflectivity exaggerates irregularities in the asteroid shape to cause this behavior. One-third of our targets show evidence for asteroid-scale concavities or bifurcation. Based on all the evidence available, we suggest that most Tholen M-class asteroids are not remnant iron cores or enstatite chondrites, but rather collisional composites of silicates and irons with compositions more analogous to stony-iron meteorites and high-iron carbonaceous chondrites.

We recorded 101 new rotation lightcurves of five Koronis family members, and then combined the new observations with previous data to determine the objects' sidereal rotation periods, spin vector orientations, and model shape solutions. The observing program was tailored specifically for spin vector analyses by determining single-apparition Lumme–Bowell solar phase coefficients, and by measuring synodic rotation periods precisely enough to unambiguously count the rotations between two consecutive oppositions, which is a prerequisite for identifying the correct sidereal period. The new data make possible first pole and shape determinations for (263) Dresda, (462) Eriphyla, and (1289) Kutaissi, and they improve the models for (277) Elvira and (534) Nassovia, two objects previously studied by Slivan et al. [Slivan, S.M., Binzel, R.P., Crespo da Silva, L.D., Kaasalainen, M., Lyndaker, M.M., Krco, M., 2003. Icarus 162, 285–307]. Our results increase the number of Koronis family spin vectors reported in the literature to fourteen, a sample which now includes the seven largest family members. The spin properties of Eriphyla (rotation period P = 8.66 h , spin vector obliquity e = 51 ° ) and Kutaissi ( P = 3.62 h , e = 165 ° ) are consistent with the markedly nonrandom distribution reported by Slivan [Slivan, S.M., 2002. Nature 419, 49–51], and explained by Vokrouhlický et al. [Vokrouhlický, D., Nesvorný, D., Bottke, W.F., 2003. Nature 425, 147–151] as the result of the effects of thermal “YORP” torques combined with solar and planetary gravitational torques. Dresda ( P = 16.81 h , e = 16 ° ) is the first prograde Koronis member whose spin obliquity and spin rate significantly differ from the clustered spin properties previously found for other prograde Koronis members; nevertheless, its spin vector is consistent with several of the spin evolution possibilities that were identified in the YORP modeling.

We report the results of an observational survey of rotation lightcurves for members of the Koronis asteroid family that we conducted using CCD imaging cameras at seven different observatories during the period 1998–2005. A total of 375 individual lightcurves yield new or refined rotation periods for the 24 survey objects (658) Asteria, (761) Brendelia, (811) Nauheima, (975) Perseverantia, (1029) La Plata, (1079) Mimosa, (1100) Arnica, (1245) Calvinia, (1336) Zeelandia, (1350) Rosselia, (1423) Jose, (1482) Sebastiana, (1618) Dawn, (1635) Bohrmann, (1725) CrAO, (1741) Giclas, (1742) Schaifers, (1848) Delvaux, (1955) McMath, (2123) Vltava, (2144) Marietta, (2224) Tucson, (2729) Urumqi, and (2985) Shakespeare. Most of the data have been calibrated to standard magnitudes. Several previously unpublished lightcurves recorded using a photoelectric photometer during the period 1987–1989 are also reported here. We present composite lightcurves and report derived synodic rotation periods. For those objects with sufficient coverage in solar phase angle we also determined Lumme–Bowell solar phase parameters, and for four objects we obtained V – R colors. Our results reduce selection biases among known rotation lightcurve parameters for Koronis family members by completing the sample down to H ≈ 11.2 , and they lay the foundation for future spin vector and shape determinations. The distribution of rotation rates in the available sample of N = 40 Koronis members is non-Maxwellian at a confidence level of 99%. It also seems to be qualitatively consistent with the effects of long-term modification by thermal YORP torques, as proposed by Vokrouhlický et al. [Vokrouhlický, D., Nesvorný, D., Bottke, W.F., 2003. Nature 425, 147–151] to explain the distribution of the ten Koronis member spin vectors that have already been determined [Slivan, S.M., 2002. Nature 419, 49–51; Slivan, S.M., Binzel, R.P., Crespo da Silva, L.D., Kaasalainen, M., Lyndaker, M.M., Krco, M., 2003. Icarus 162, 285–307].

International audience; Aims:We present physical models of ten asteroids obtained by means of lightcurve inversion. A substantial part of the photometric data was observed by amateur astronomers. We emphasize the importance of a coordinated network of observers that will be of extreme importance for future all-sky asteroid photometric surveys. Methods: The lightcurve inversion method was used to derive spin states and shape models of the asteroids. Results: We derived spin states and shape model for ten new asteroids: (110) Lydia, (125) Liberatrix, (130) Elektra, (165) Loreley, (196) Philomela, (218) Bianca, (306) Unitas, (423) Diotima, (776) Berbericia, and (944) Hidalgo. This increases the number of asteroid models up to nearly one hundred.

In this chapter, two patients are presented that were each seen several times for neuropsychological assessment and opinion, over a period of months and years. This chapter illustrates and discusses issues related to serial assessment, the progression of symptoms and increasing familiarity with the cases. The first patient presented with subtle subjective cognitive change and underwent subsequent serial assessment over several years to help clarify the nature of her condition and monitor change in the context of other neurological investigations. Issues are discussed concerning the role of the patient’s account in understanding her condition and the utility of increased familiarity with the patient over time. The second patient underwent neurosurgery as a treatment for intractable epilepsy. The assessments addressed questions about risk to his cognition, the cognitive outcome of surgery, and the role of psychological and behavioural disturbance. Issues of test selection and the psychometric evaluation of change are discussed.

The dwarf planet Ceres is likely differentiated similar to the terrestrial planets but with a water/ice dominated mantle and an aqueously altered crust. Detailed modeling of Ceres' phase function has never been performed to understand its surface properties. The Dawn spacecraft began orbital science operations at the dwarf planet in April 2015. We observed Ceres with flight spares of the seven Dawn Framing Camera color filters mounted on ground-based telescopes over the course of three years to model its phase function versus wavelength. Our analysis shows that the modeled geometric albedos derived from both the IAU HG model and the Hapke model are consistent with a flat and featureless spectrum of Ceres, although the values are ~10% higher than previous measurements. Our models also suggest a wavelength dependence of Ceres' phase function. The IAU G-parameter and the Hapke single-particle phase function parameter, g, are both consistent with decreasing (shallower) phase slope with increasing wavelength. Such a wavelength dependence of phase function is consistent with reddening of spectral slope with increasing phase angle, or phase-reddening. This phase reddening is consistent with previous spectra of Ceres obtained at various phase angles archived in the literature, and consistent with the fact that the modeled geometric albedo spectrum of Ceres is the bluest of all spectra because it represents the spectrum at 0 degree phase angle. Ground-based FC color filter lightcurve data are consistent with HST albedo maps confirming that Ceres' lightcurve is dominated by albedo and not shape. We detected a positive correlation between 1.1-micron absorption band depth and geometric albedo suggesting brighter areas on Ceres have absorption bands that are deeper., Comment: 40 pages, 9 figures, 5 tables. Accepted for publication in Icarus

Photometric data on 17 binary near-Earth asteroids (15 of them are certain detections, two are probables) were analysed and characteristic properties of the near-Earth asteroid (NEA) binary population were inferred. We have found that binary systems with a secondary-to-primary mean diameter ratio D s / D p ⩾ 0.18 concentrate among NEAs smaller than 2 km in diameter; the abundance of such binaries decreases significantly among larger NEAs. Secondaries show an upper size limit of D s = 0.5 – 1 km . Systems with D s / D p ⩽ 0.5 are abundant but larger satellites are significantly less common. Primaries have spheroidal shapes and they rotate rapidly, with periods concentrating between 2.2 to 2.8 h and with a tail of the distribution up to ∼4 h. The fast rotators are close to the critical spin for rubble piles with bulk densities about 2 g/cm3. Orbital periods show an apparent cut-off at P orb ∼ 11 h ; closer systems with shorter orbital periods have not been discovered, which is consistent with the Roche limit for strengthless bodies. Secondaries are more elongated on average than primaries. Most, but not all, of their rotations appear to be synchronized with the orbital motion; nonsynchronous secondary rotations may occur especially among wider systems with P orb > 20 h. The specific total angular momentum of most of the binary systems is similar to within ±20% and close to the angular momentum of a sphere with the same total mass and density, rotating at the disruption limit; this suggests that the binaries were created by mechanism(s) related to rotation near the critical limit and that they neither gained nor lost significant amounts of angular momentum during or since formation. A comparison with six small asynchronous binaries detected in the main belt of asteroids suggests that the population extends beyond the region of terrestrial planets, but with characteristics shifted to larger sizes and longer periods. The estimated mean proportion of binaries with D s / D p ⩾ 0.18 among NEAs larger than 0.3 km is 15 ± 4 % . Among fastest rotating NEAs larger than 0.3 km with periods between 2.2 and 2.8 h, the mean proportion of such binaries is (66+10−12)%.

This study explores the multi-dimensionality of organizational commitment of volunteer chamber of commerce board members using the Meyer and Allen (1997) scale. The effect of organizational commitment on desirable board member roles is also tested. Theory is developed by uniting past research in both organizational commitment and employee motivation. A proposed scale is tested using Confirmatory Factor Analysis with data gathered from 616 respondents at 116 chambers of commerce in 36 states. Structural Equations Modeling is then used to examine the effects of organizational commitment on several critical roles the board member is hoped to perform. Unlike prior research using Meyer and Allen’s (1997) scale that focused on paid employees, our results indicate that normative, affective, and continuance commitment based on low alternatives are the three distinct constructs applicable to volunteer employees. Moreover, these components have a positive effect on board member’s roles.

Urban runoff samples were collected in a 1-year period in the Santa Monica Bay watershed during both dry and storm periods and analyzed for polychlorinated dioxins, polychlorinated furans, and polychlorinated naphthalenes. Trace concentrations were found in nearly all of the samples collected. During storms polychlorinated dioxin and polychlorinated furan concentrations peaked. The congener and isomer profiles resemble profiles found in lake sediments and rainwater more than they resemble profiles found in urban sources such as dioxins from incinerators or dioxins in contaminated commercial products. Runoff from open land use had lower concentrations than runoff from developed land uses.

Life Cycle Assessment is becoming an important tool for guiding environmental design improvements in the automotive industry. This paper reports the life cycle inventory profiles for two fuel tank systems based on a collaborative effort between the National Pollution Prevention Center at the University of Michigan, General Motors Research and Development, and the National Risk Management Research Laboratory of the U.S. Environmental Protection Agency. Two 31 gallon functionally equivalent fuel tank systems used on a 1996 light duty vehicle were investigated: a multi-layer HDPE tank with a steel shield and PVC coated steel straps, and a steel tank with a HDPE shield and painted steel straps. Overall, the HDPE fuel tank system is environmentally preferable to the steel tank system based on the set of inventory results presented in this investigation. The Life Cycle Inventory analysis indicated lower energy burdens for the HDPE tank system and comparable solid waste burdens for both systems. The total life cycle energy consumption for the steel and HDPE tank systems were 4.9 GJ and 3.6 GJ per tank, respectively. The energy consumption and most of the air pollutants inventoried occurred as a consequence of the use phase. The solid wastes were generated primatily during the material production phase for the steel tank (13 kg) and during the end-of-life management phase for the HDPE tank (14 kg). This study also highlights data analysis and modeling challenges, including manufacturing and use phase allocation methods.

To assess levels of chlorinated contaminants in breast milk, we measured organochlorine pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in breast milk samples collected in 1994 according to the World Health Organization protocol from 92 donors that were representative of regional populations in southern Kazakstan. High levels (10-120 pg/g fat) of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic of the PCDD/PCDF congeners, were found in breast milk samples from an agricultural region. TCDD was the major contributor (75%) to the international toxicity equivalents of these samples. The same distinctive PCDD/PCDF congener pattern was found in 15 breast milk samples and 4 serum samples collected in 1996 in a follow-up study, and has now been confirmed by three analytical laboratories. Images Figure 1 Figure 2 Figure 3 Figure 4

Remote sensing measurements of CO emissions from onroad vehicles were made in California in 1991 and in Michigan in 1992. It was determined that both fleets had a small linear increase in the high emitter frequency (vehicles emitting more than 4% CO) as a function of vehicle age for 1986 and newer model vehicles. Although high emitting vehicles were only a small minority of the fleet, they had a dominant impact on the mean CO and total CO emitted by the fleet. In Michigan, the highest emitting 5% of passenger cars generated 45% of the CO from cars. In California, the highest emitting 5% of passenger cars generated 38% of the CO from cars. There was a high correlation between the mean CO emitted by each model year of vehicle and the frequency of high emitting vehicles within the model year for both the Michigan and California fleets. The frequency of high emitters within any model year had no obvious relation to that model year's certification standards. The high emitter frequencies for vehicles less than nine years old were very similar for the California and Michigan fleets. An increase in the high emitter frequency in the ten-year-old and older Michigan passenger car fleet (relative to the California passenger car fleet), suggests, but does not conclusively demonstrate, that the rate of high emitters in Michigan and California is reduced by the inspection and maintenance (I/M) programs.

Current amount of ~500 asteroid models derived from the disk-integrated photometry by the lightcurve inversion method allows us to study not only the spin-vector properties of the whole population of MBAs, but also of several individual collisional families. We create a data set of 152 asteroids that were identified by the HCM method as members of ten collisional families, among them are 31 newly derived unique models and 24 new models with well-constrained pole-ecliptic latitudes of the spin axes. The remaining models are adopted from the DAMIT database or the literature. We revise the preliminary family membership identification by the HCM method according to several additional criteria - taxonomic type, color, albedo, maximum Yarkovsky semi-major axis drift and the consistency with the size-frequency distribution of each family, and consequently we remove interlopers. We then present the spin-vector distributions for eight asteroidal families. We use a combined orbital- and spin-evolution model to explain the observed spin-vector properties of objects among collisional families. In general, we observe for studied families similar trends in the (a_p, \beta) space: (i) larger asteroids are situated in the proximity of the center of the family; (ii) asteroids with \beta>0{\deg} are usually found to the right from the family center; (iii) on the other hand, asteroids with \beta0{\deg} or \beta, Comment: Accepted for publication in A&A (September 16, 2013)

Analysis of CCD photometric observations of the Hungaria asteroid 1727 Mette made in 2013 January shows that the asteroid is a binary system. A bimodal lightcurve for the primary has a period 2.98109 ± 0.00007 h with an amplitude of 0.33 ± 0.01 mag. This makes the primary one of the more elongated objects in the small binary population. The orbital period of the satellite is 20.99 ± 0.02 h. Based on the depth of the mutual events, the satellite-primary diameter ratio is estimated to be D(s)/D(p) = 0.21 ± 0.02.

Chickens were used as a model for foraging animals to examine the bioavailability of all 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) from soil. Three groups of chickens were exposed through their diet to soil contaminated with PCDD/PCDFs at less than 0.5 pg/g I-TEQ (control group), 42 pg/g I-TEQ (low exposure group), and 460 pg/g I-TEQs (high exposure group). Eggs, tissues, feces and feed were analysed throughout the exposure and depuration period. Daily intake was estimated at 2.5 ng/kg-day for the high and 0.3 ng/kg-day for the low exposure groups. Bioavailability was chlorination-dependent ranging from 80% for tetrachlorinated to less than 10% for octachlorinated congeners. During exposure, tissue distribution was congener-dependent with 5-30% of the intake excreted in the eggs, 7-54% deposited in the adipose and less than 1% present in the liver. On a fat weight basis, the highest concentrations were observed in the liver, implying that mechanisms other than lipid solubility operate in that tissue. Bioconcentration factors and elimination half-lives were also congener- and tissue-dependent. Results from this study indicate that animals foraging on soil contaminated at low ppt PCDD/PCDF levels may bioaccumulate these compounds to unacceptable levels.

Soil and ash surface samples (n= 44) were collected from three historical metal recovery facilities where copper scrap was a dominant feed stream, three sites of open burning where evidence of copper recovery was visible, and from a railroad car incineration facility. Concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are in the low parts per billion range with PCDF concentrations significantly lower in samples from the railroad car facility. In fly ash from a copper wire and aluminum scrap recovery facility, PCDD and PCDF concentrations are high, 50 and 460 ppm. Consistent with that cited for other combustion sources, ratios of PCDF to PCDD are mostly greater than 1. However, a lower ratio (0.4), is observed in samples from the railroad car incineration facility. OCDF and OCDD are significantly correlated with 2,3,7,8-TCDD toxicity equivalents (TEQ). These congeners may be inexpensively analyzed and may be useful as indicator chemicals at similar sites and facilities. Further investigations of metal recovery facilities and open burn sites worldwide are necessary.

The original publication is available at www.aanda.org. Copyright ESO.; International audience; The spin state of small asteroids can change on a long timescale by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, the net torque that arises from anisotropically scattered sunlight and proper thermal radiation from an irregularly-shaped asteroid. The secular change in the rotation period caused by the YORP effect can be detected by analysis of asteroid photometric lightcurves. We analyzed photometric lightcurves of near-Earth asteroids (1865) Cerberus, (2100) Ra-Shalom, and (3103) Eger with the aim to detect possible deviations from the constant rotation caused by the YORP effect. We carried out new photometric observations of the three asteroids, combined the new lightcurves with archived data, and used the lightcurve inversion method to model the asteroid shape, pole direction, and rotation rate. The YORP effect was modeled as a linear change in the rotation rate in time d\omega /dt. Values of d\omega/ dt derived from observations were compared with the values predicted by theory. We derived physical models for all three asteroids. We had to model Eger as a nonconvex body because the convex model failed to fit the lightcurves observed at high phase angles. We probably detected the acceleration of the rotation rate of Eger d\omega / dt = (1.4 +/- 0.6) x 10^{-8} rad/d (3\sigma error), which corresponds to a decrease in the rotation period by 4.2 ms/yr. The photometry of Cerberus and Ra-Shalom was consistent with a constant-period model, and no secular change in the spin rate was detected. We could only constrain maximum values of |d\omega / dt| < 8 x 10^{-9} rad/d for Cerberus, and |d\omega / dt| < 3 x 10^{-8} rad/d for Ra-Shalom.

We will briefly discuss vehicle emissions and the vehicle emissions inventory before reviewing remote-sensing technology for exhaust emissions and remote-sensing applications that help characterize and minimize exhaust emissions in the real world. Remote sensing is the only method available that can measure the HC and CO exhaust emission rates of large numbers of individual in-use vehicles. These measurements have helped focus attention on the problem of in-use emissions from malfunctioning and illegally altered vehicles. The method has a bright future as an aid in understanding in-use emissions, a monitor of progress in reducing fleet emission rates, and as an IM and enforcement tool. 11 refs., 2 figs.