- ID:
- ivo://CDS.VizieR/J/AJ/157/120
- Title:
- TNOs and Centaurs observed within the DES
- Short Name:
- J/AJ/157/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Trans-Neptunian objects (TNOs) are a source of invaluable information to access the history and evolution of the outer solar system. However, observing these faint objects is a difficult task. As a consequence, important properties such as size and albedo are known for only a small fraction of them. Now, with the results from deep sky surveys and the Gaia space mission, a new exciting era is within reach as accurate predictions of stellar occultations by numerous distant small solar system bodies become available. From them, diameters with kilometer accuracies can be determined. Albedos, in turn, can be obtained from diameters and absolute magnitudes. We use observations from the Dark Energy Survey (DES) from 2012 November until 2016 February, amounting to 4292847 charge-coupled device (CCD) frames. We searched them for all known small solar system bodies and recovered a total of 202 TNOs and Centaurs, 63 of which have been discovered by the DES collaboration as of the date of submission. Their positions were determined using the Gaia Data Release 2 (Cat. I/345) as reference and their orbits were refined. Stellar occultations were then predicted using these refined orbits plus stellar positions from Gaia. These predictions are maintained, and updated, in a dedicated web service. The techniques developed here are also part of an ambitious preparation to use the data from the Large Synoptic Survey Telescope (LSST), that expects to obtain accurate positions and multifilter photometry for tens of thousands of TNOs.
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- ID:
- ivo://CDS.VizieR/J/AJ/153/116
- Title:
- Trojan asteroids in the Kepler campaign 6 field
- Short Name:
- J/AJ/153/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a Kepler spacecraft survey during the K2 mission to characterize the rotational properties of 56 Trojan asteroids in the L4 cloud. More than one rotational period was observed for 51 of these targets, allowing for well constrained lightcurve rotation periods and amplitudes, five of which are found to be in conflict with previously published values. We find ~10% of objects have rotational periods longer than 100hr, an excess of slow rotators 10 times larger than suggested from the literature. Investigation of the rotational frequencies of our Kepler sample when combined with high-quality lightcurves in the literature reveals the distribution of rotational frequencies is non-Maxwellian even when consideration is given to size-dependent variations in rotational rate. From investigation of lightcurve shapes and amplitudes, we estimate the binary fraction within the Trojan population to be ~6%-36% depending on the methodology utilized to identify binary candidates.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A125
- Title:
- (174567) Varda multi-chord stellar occultation
- Short Name:
- J/A+A/643/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here results of the first-ever recorded stellar occultation by the large trans-Neptunian object (174567) Varda that was observed on September 10th, 2018. Varda belongs to the high-inclination dynamically excited population, and has a satellite, Ilmare, which is half the size of Varda.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A48
- Title:
- V-band photometry of asteroids from ASAS-SN
- Short Name:
- J/A+A/654/A48
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present V-band photometry of the 20000 brightest asteroids using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) between 2012 and 2018. We were able to apply the convex inversion method to more than 5000 asteroids with more than 60 good measurements in order to derive their sidereal rotation periods, spin axis orientations, and shape models. We derive unique spin state and shape solutions for 760 asteroids, including 163 new determinations. This corresponds to a success rate of about 15%, which is significantly higher than the success rate previously achieved using photometry from surveys. We derive the first sidereal rotation periods for additional 69 asteroids. We find good agreement in spin periods and pole orientations for objects with prior solutions. We obtain a statistical sample of asteroid physical properties that is sufficient for the detection of several previously known trends, such as the underrepresentation of slow rotators in current databases, and the anisotropic distribution of spin orientations driven by the nongravitational forces. We also investigate the dependence of spin orientations on the rotation period. Since 2018, ASAS-SNhas been observing the sky with higher cadence and a deeper limiting magnitude, which will lead to many more new solutions in just a few years.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/4400
- Title:
- Veritas family members Yarkovsky drift rates
- Short Name:
- J/MNRAS/469/4400
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The age of a young asteroid family can be determined by tracking the orbits of family members backward in time and showing that they converge at some time in the past. Here we consider the Veritas family. We find that the membership of the Veritas family increased enormously since the last detailed analysis of the family. Using backward integration, we confirm the convergence of nodal longitudes {Omega}, and, for the first time, also obtain a simultaneous convergence of pericenter longitudes {varpi}. The Veritas family is found to be 8.23^+0.37^_-0.31_Myr old. To obtain a tight convergence of {Omega} and {varpi}, as expected from low ejection speeds of fragments, the Yarkovsky effect needs to be included in the modeling of the past orbital histories of Veritas family members. Using this method, we compute the Yarkovsky semi-major axis drift rates, d_a_/dt, for 274 member asteroids. The distribution of d_a_/dt values is consistent with a population of C-type objects with low densities and low thermal conductivities. The accuracy of individual d_a_/dt measurements is limited by the effect of close encounters of member asteroids to (1) Ceres and other massive asteroids, which cannot be evaluated with confidence.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/248
- Title:
- (4) Vesta adopted polarimetric light curves
- Short Name:
- J/MNRAS/456/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of the in situ exploration of the asteroid (4) Vesta by the Dawn spacecraft open new perspectives in the field of interpretation of remote-sensing polarimetric measurements of asteroids. (4) Vesta has long been known to be the only asteroid exhibiting a cyclic variation of the degree of linear polarization of the sunlight scattered by its surface, with a period which is synchronous with the object's rotation. This variation must be the consequence of some heterogeneity of the asteroid's surface, including regions characterized by different albedo, or composition, or regolith properties, or a combination of the above features. For a long time, this kind of conclusion has remained essentially qualitative. Now, after the extensive exploration of Vesta's surface by Dawn, it is possible to interpret the data set of polarimetric measurements of Vesta, including some unpublished data presented here for the first time, in terms of a correspondence between the degree of linear polarization and the variation of local properties of the surface visible to ground-based observers during Vesta's rotation, as seen at different epochs and under different illumination conditions. This makes it possible to refine our knowledge of the empirical relation between polarization properties and albedo, which is commonly used to derive the albedo from remote-sensing measurements of linear polarization of atmosphereless Solar system bodies.
- ID:
- ivo://CDS.VizieR/J/A+A/577/A35
- Title:
- Visible colors of Centaurs and KBOs
- Short Name:
- J/A+A/577/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since the discovery of the Kuiper Belt, broadband surface colors were thoroughly studied as a first approximation to the objects reflectivity spectra. Visible colors (BVRI) have proven to be a reasonable proxy for real spectra, which are rather linear in this range. On the contrary, near-IR colors (JHK bands) could be misleading when absorption features of ices are present in the spectra. Although the physical and chemical information provided by colors are rather limited, broadband photometry remains the best tool for establishing the bulk surface properties of KBOs and Centaurs. In this work, we explore for the first time general, recurrent effects in the study of visible colors that could affect the interpretation of the scientific results: i) how a correlation could be missed or weaken due to the data error bars, ii) the "risk" of missing-out an existing trend due to low sampling, and the possibility to make quantified predictions on the sample size needed to detect a trend at a given significance level, assuming the sample is unbiased, iii) the use of partial correlations to disentangle the mutual effect of two or more (physical) parameters, iv) the sensitivity of the "reddening line" tool to the central wavelength of the filters used. To illustrate and apply these new tools, we have compiled the visible colors and orbital parameters of about 370 objects available in the literature, assumed, by default, as unbiased samples, and carried-out the "traditional" analysis per dynamical family. Our results show in particular how: a) data error-bars impose a limit on the detectable correlations regardless of sample size and, therefore, once that limit is achieved it is important to diminish the error-bars but pointless to enlarge the sampling with the same or larger errors; b) almost all dynamical families still require larger samplings to "ensure" the detection of correlations stronger than +/-0.5, i.e. correlations that may "explain" ~25% or more of the color variability; c) the correlation strength between (V-R) vs. (R-I) is systematically lower than the one between (B-V) vs. (V-R) and not related with error-bar differences between these colors; d) it is statistically equivalent to use any of the different "flavors" of orbital excitation or collisional velocity parameters regarding the famous color-inclination correlation among Classical KBOs --- which no longer evidences to be a strong correlation --- whereas the inclination and Tisserand parameter relative to Neptune cannot be separated from one another; and e) Classical KBOs are the only dynamical family which evidences for neither (B-V) vs. (V-R) nor (V-R) vs. (R-I) correlations, being, therefore, the family with the most unpredictable visible surface reflectivities.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A115
- Title:
- VISTA-VHS (MOVIS) minor planets NIR photometry
- Short Name:
- J/A+A/591/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The NIR photometric data of minor planets observed by the VISTA-VHS survey. This survey uses Y, J, H, and Ks filters for imaging the entire sky of the southern hemisphere. A total of 39947 Solar System objects were detected in the VISTA VHS Data Release 3. The detections found include: 52 NEAs, 325 Mars Crossers, 515 Hungaria asteroids, 38428 Main Belt asteroids, 146 Cybele asteroid, 147 Hilda asteroids, 270 Trojans, 13 comets, 12 Kuiper Belt objects, and Neptune with its 4 satellites. About 34998 of these objects were imaged with at least two different filters.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A6
- Title:
- VLT/SPHERE/ZIMPOL images of Vesta
- Short Name:
- J/A+A/623/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Over the past decades, several interplanetary missions have studied small bodies in situ, leading to major advances in our understanding of their geological and geophysical properties. These missions, however, have had a limited number of targets. Among them, the NASA Dawn mission has characterised in detail the topography and albedo variegation across the surface of asteroid (4) Vesta down to a spatial resolution of ~20m/pixel scale. Here our aim was to determine how much topographic and albedo information can be retrieved from the ground with VLT/SPHERE in the case of Vesta, having a former space mission (Dawn) providing us with the ground truth that can be used as a benchmark. We observed Vesta with VLT/SPHERE/ZIMPOL as part of our ESO large programme (ID 199.C-0074) at six different epochs, and deconvolved the collected images with a parametric point spread function (PSF). We then compared our images with synthetic views of Vesta generated from the 3D shape model of the Dawn mission, on which we projected Vesta's albedo information. We show that the deconvolution of the VLT/SPHERE images with a parametric PSF allows the retrieval of the main topographic and albedo features present across the surface of Vesta down to a spatial resolution of ~20-30km. Contour extraction shows an accuracy of ~1-pixel (3.6mas). The present study provides the very first quantitative estimate of the accuracy of ground-based adaptive-optics imaging observations of asteroid surfaces. In the case of Vesta, the upcoming generation of 30-40m telescopes (ELT, TMT, GMT) should in principle be able to resolve all of the main features present across its surface, including the troughs and the north-south crater dichotomy, provided that they operate at the diffraction limit.
- ID:
- ivo://CDS.VizieR/J/ApJS/242/15
- Title:
- VRI photometry & taxonomy for >~2000 MBAs
- Short Name:
- J/ApJS/242/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here multiband photometry for over 2000 Main-Belt asteroids. For each target, we report the probabilistic taxonomy using the measured V-R and V-I colors in combination with a machine-learning-generated decision surface in color-color space. Through this method, we classify >85% of our targets as one the four main Bus-DeMeo complexes: S-, C-, X-, or D-type. Roughly one-third of our targets have a known associated dynamic family, with 69 families represented in our data. Within uncertainties, our results show no discernible difference in taxonomic distribution between family members and non-family members. Nine of the sixty-nine families represented in our observed sample had 20 or more members present, and therefore, we investigate the taxonomy of these families in more detail and find excellent agreement with the literature. Out of these nine well-sampled families, our data show that the Themis, Koronis, Hygiea, Massalia, and Eunomia families display a high degree of taxonomic homogeneity and that the Vesta, Flora, Nysa-Polana, and Eos families show a significant level of mixture in taxonomies. Using the taxonomic purity and the degree of dispersion in observed colors for each of the nine well-sampled collisional families, we also speculate which of these families potentially originated from a differentiated parent body and/or is a family with a possible undetermined nested family. In addition, we obtained sufficient photometric data for 433 of our targets to extract reliable rotation periods and observe no obvious correlation between rotation properties and family membership.
