- ID:
- ivo://CDS.VizieR/J/AJ/133/1247
- Title:
- Solar system survey with Spacewatch
- Short Name:
- J/AJ/133/1247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have completed a low-inclination ecliptic survey for distant and slow-moving bright objects in the outer solar system. This survey used data taken over 34 months by the University of Arizona's Spacewatch Project based at Steward Observatory, Kitt Peak. Spacewatch revisits the same sky area every three to seven nights in order to track cohorts of main-belt asteroids. This survey used a multiple-night detection scheme to extend our rate sensitivity to as low as 0.012"/hr. When combined with our plate scale and flux sensitivity (V~21), this survey was sensitive to Mars-sized objects out to 300AU and Jupiter-sized planets out to 1200AU. The survey covered approximately 8000deg^2^ of raw sky, mostly within 10{deg} of the ecliptic but away from the Galactic center. An automated motion detection program was modified for this multinight search and processed approximately 2 terabytes of imagery into motion candidates. This survey discovered 2003 MW12, currently the tenth largest classical Kuiper Belt object. In addition, several known large Kuiper Belt objects and Centaurs were detected, and the detections were used with a model of our observational biases to make population estimates as a check on our survey efficiency. We found no large objects at low inclinations despite having sufficient sensitivity in both flux and rate to see them out as far as 1200AU. For low inclinations, we can rule out more than one to two Pluto-sized objects out to 100AU and one to two Mars-sized objects to 200AU.
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- ID:
- ivo://CDS.VizieR/J/A+A/650/A129
- Title:
- SPHERE (87) Sylvia images
- Short Name:
- J/A+A/650/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dynamical models of Solar System evolution have suggested that the so-called P- and D-type volatile-rich asteroids formed in the outer Solar System beyond Neptune's orbit and may be genetically related to the Jupiter Trojans, comets, and small Kuiper belt objects (KBOs). Indeed, the spectral properties of P- and D-type asteroids resemble that of anhydrous cometary dust. We aim to gain insights into the above classes of bodies by characterizing the internal structure of a large P- and D-type asteroid. We report high-angular-resolution imaging observations of the P-type asteroid (87) Sylvia with the the Very Large Telescope (VLT) Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. These images were used to reconstruct the 3D shape of Sylvia. Our images together with those obtained in the past with large ground-based telescopes were used to study the dynamics of its two satellites. We also modeled Sylvia's thermal evolution. The shape of Sylvia appears flattened and elongated (a/b~1.45; a/c~1.84). We derive a volume-equivalent diameter of 271+/-5km and a low density of 1378+/-45kg/m^3^. The two satellites orbit Sylvia on circular, equatorial orbits. The oblateness of Sylvia should imply a detectable nodal precession which contrasts with the fully-Keplerian dynamics of its two satellites. This reveals an inhomogeneous internal structure, suggesting that Sylvia is differentiated. Sylvia's low density and differentiated interior can be explained by partial melting and mass redistribution through water percolation. The outer shell should be composed of material similar to interplanetary dust particles (IDPs) and the core should be similar to aqueously altered IDPs or carbonaceous chondrite meteorites such as the Tagish Lake meteorite. Numerical simulations of the thermal evolution of Sylvia show that for a body of such a size, partial melting was unavoidable due to the decay of long-lived radionuclides. In addition, we show that bodies as small as 130-150km in diameter should have followed a similar thermal evolution, while smaller objects, such as comets and the KBO Arrokoth, must have remained pristine, which is in agreement with in situ observations of these bodies. NASA Lucy mission target (617) Patroclus (diameter ~140km) may, however, be differentiated.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A132
- Title:
- SPHERE/ZIMPOL (41) Daphne images
- Short Name:
- J/A+A/623/A132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been predicted to be homogeneous, based on their compositional similarity as inferred from spectroscopy (Vernazza et al., 2016AJ....152..154G) and numerical modeling of their early thermal evolution (Bland & Travis, 2017, Sci. Adv. 3, e1602514). Here we aim to test this hypothesis by deriving the density of the CM-like asteroid (41) Daphne from detailed modeling of its shape and the orbit of its small satellite. We observed Daphne and its satellite within our imaging survey with the Very Large Telescope extreme adaptive-optics SPHERE/ZIMPOL camera (ID 199.C-0074, PI P. Vernazza) and complemented this data set with earlier Keck/NIRC2 and VLT/NACO observations. We analyzed the dynamics of the satellite with our Genoid meta-heuristic algorithm. Combining our high-angular resolution images with optical lightcurves and stellar occultations, we determine the spin period, orientation, and 3-D shape, using our ADAM shape modeling algorithm. The satellite orbits Daphne on an equatorial, quasi-circular, prograde orbit, like the satellites of many other large main-belt asteroids. The shape model of Daphne reveals several large flat areas that could be large impact craters. The mass determined from this orbit combined with the volume computed from the shape model implies a density for Daphne of 1.77+/-0.26g/cm^3^ (3{sigma}). This density is consistent with a primordial CM-like homogeneous internal structure with some level of macroporosity (~17%). Based on our analysis of the density of Daphne and 75 other Ch/Cgh-type asteroids gathered from the literature, we conclude that the primordial internal structure of the CM parent bodies was homogeneous.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A154
- Title:
- SPHERE/ZIMPOL (89) Julia images
- Short Name:
- J/A+A/618/A154
- Date:
- 23 Mar 2022 16:27:22
- Publisher:
- CDS
- Description:
- The vast majority of the geophysical and geological constraints (e.g., internal structure, cratering history) for main-belt asteroids have so far been obtained via dedicated interplanetary missions (e.g., ESA Rosetta, NASA Dawn). The high angular resolution of SPHERE/ZIMPOL, the new-generation visible adaptive-optics camera at ESO VLT, implies that these science objectives can now be investigated from the ground for a large fraction of D>=100km main-belt asteroids. The sharp images acquired by this instrument can be used to accurately constrain the shape and thus volume of these bodies (hence density when combined with mass estimates) and to characterize the distribution and topography of D>=30km craters across their surfaces. Here, via several complementary approaches, we evaluated the recently proposed hypothesis that the S-type asteroid (89) Julia is the parent body of a small compact asteroid family that formed via a cratering collisional event. We observed (89) Julia with VLT/SPHERE/ZIMPOL throughout its rotation, derived its 3D shape, and performed a reconnaissance and characterization of the largest craters. We also performed numerical simulations to first confirm the existence of the Julia family and to determine its age and the size of the impact crater at its origin. Finally, we utilized the images/3D shape in an attempt to identify the origin location of the small collisional family. On the one hand, our VLT/SPHERE observations reveal the presence of a large crater (D~75km) in Julia's southern hemisphere. On the other hand, our numerical simulations suggest that (89) Julia was impacted 30-120Myrs ago by a D~8km asteroid, thereby creating a D>=60km impact crater at the surface of Julia. Given the small size of the impactor, the obliquity of Julia and the particular orientation of the family in the (a,i) space, the imaged impact crater is likely to be the origin of the family. New doors into ground-based asteroid exploration, namely, geophysics and geology, are being opened thanks to the unique capabilities of VLT/SPHERE. Also, the present work may represent the beginning of a new era of asteroid-family studies. In the fields of geophysics, geology, and asteroid family studies, the future will only get brighter with the forthcoming arrival of 30-40m class telescopes like ELT, TMT, and GMT.
- ID:
- ivo://CDS.VizieR/J/A+A/639/A134
- Title:
- The large TNO 2002 TC302
- Short Name:
- J/A+A/639/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On 28th January 2018, the large Trans-Neptunian Object 2002 TC_302_ occulted a m_v_~15.3 star with designation 593-005847 in the UCAC4 stellar catalog, corresponding to Gaia source 130957813463146112. Twelve positive occultation chords were obtained from Italy, France, Slovenia and Switzerland. Also, four negative detections were obtained near the north and south limbs. This represents the best observed stellar occultation by a TNO other than Pluto in terms of the number of chords published thus far. From the twelve chords, an accurate elliptical fit to the instantaneous projection of the body can be obtained, compatible with the near misses. The resulting ellipse has major and minor axes of 543+/-18km and 460+/-11km, respectively, with a position angle of 3+/-1 degrees for the minor axis. This information, combined with rotational light curves obtained with the 1.5-m telescope at Sierra Nevada Observatory and the 1.23-m telescope at Calar Alto observatory, allows us to derive possible three-dimensional shapes and density estimations for the body based on hydrostatic equilibrium assumptions. The effective diameter in equivalent area is around 84km smaller than the radiometrically derived diameter using thermal data from Herschel and Spitzer Space Telescopes. This might indicate the existence of an unresolved satellite of up to ~300km in diameter, to account for all the thermal flux, although the occultation and thermal diameters are compatible within their error bars given the considerable uncertainty of the thermal results. The existence of a potential satellite also appears to be consistent with other ground-based data presented here. From the effective occultation diameter combined with absolute magnitude measurements we derive a geometric albedo of 0.147+/-0.005, which would be somewhat smaller if 2002 TC_302_ has a satellite. The best occultation light curves do not show any signs of ring features or any signatures of a global atmosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A109
- Title:
- The SkyMapper DR3 SSOs
- Short Name:
- J/A+A/658/A109
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The populations of small bodies of the Solar System (asteroids, comets, and Kuiper Belt objects) are used to constrain the origin and evolution of the Solar System. Their orbital distribution and composition distribution are both required to track the dynamical pathway from their formation regions to their current locations. We aim to increase the sample of Solar System objects (SSOs) that have multifilter photometry and compositional taxonomy. Methods. We searched for moving objects in the SkyMapper Southern Survey. We used the predicted SSO positions to extract photometry and astrometry from the SkyMapper frames. We then applied a suite of filters to clean the catalog from false-positive detections. We finally used the near-simultaneous photometry to assign a taxonomic class to objects. We release a catalog of 880,528 individual observations, consisting of 205515 known and unique SSOs. The catalog completeness is estimated to be about 97% down to V=18mag and the purity is higher than 95% for known SSOs. The near-simultaneous photometry provides either three, two, or a single color that we use to classify 117356 SSOs with a scheme consistent with the widely used Bus-DeMeo taxonomy. The present catalog contributes significantly to the sample of asteroids with known surface properties (about 40% of main-belt asteroids down to an absolute magnitude of 16). We will release more observations of SSOs with future SkyMapper data releases.
- 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/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/I/334
- Title:
- W1J00 and W2J00 Transit Circle Catalogs
- Short Name:
- I/334
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- W1J00. We present the result of observations made with the Six-inch Transit Circle in Washington, D.C., between September 1977 and July 1982. The catalog, called W1J00, contains mean positions of 7267 stars, all but five are north of -30 degrees declination, and 4383 observations of solar system objects. Positions of stars are for mean epoch of observation, on equator and equinox J2000.0. Positions of solar system objects are apparent places. Error estimates are about 100mas per coordinate for the majority of stars. W2J00. We present the result of observations made with the Six-inch Transit Circle in Washington, D.C. and the Seven-inch Transit Circle at the Black Birch station near Blenheim, New Zealand between April 1985 and February 1996. The catalog, called W2J00, contains mean positions of 44,395 globally distributed stars, 5048 observations of the planets, and 6518 observations of the brighter minor planets. Positions of stars are for mean epoch of observation, on equator and equinox J2000.0. Positions of solar system objects are apparent places. Error estimates are about 75mas per coordinate for the majority of stars.
