- ID:
- ivo://CDS.VizieR/J/A+A/599/A29
- Title:
- MIR brightness contrast of Saturn's rings
- Short Name:
- J/A+A/599/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the mid-infrared (MIR) characteristics of Saturn's rings. We collected and analyzed MIR high spatial resolution images of Saturn's rings obtained in January 2008 and April 2005 with COMICS mounted on Subaru Telescope, and investigated the spatial variation in the surface brightness of the rings in multiple bands in the MIR. We also composed the spectral energy distributions (SEDs) of the C, B, and A rings and the Cassini Division, and estimated the temperatures of the rings from the SEDs assuming the optical depths. We find that the C ring and the Cassini Division were warmer than the B and A rings in 2008, which could be accounted for by their lower albedos, lower optical depths, and smaller self-shadowing effect. We also find that the C ring and the Cassini Division were considerably brighter than the B and A rings in the MIR in 2008 and the radial contrast of the ring brightness is the inverse of that in 2005, which is interpreted as a result of a seasonal effect with changing elevations of the sun and observer above the ring plane.
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- ID:
- ivo://CDS.VizieR/J/A+A/655/A47
- Title:
- MOOJa catalogs for Solar System Objects
- Short Name:
- J/A+A/655/A47
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The Javalambre Photometric Local Universe Survey (J-PLUS) is an observational campaign that aims to obtain photometry in 12 ultraviolet-visible filters (0.3-1um) over ~8500deg^2^ of the sky observable from Javalambre (Teruel, Spain). Due to its characteristics and observation strategy, this survey will allow a great number of Solar System small bodies to be analyzed, and with improved spectrophotometric resolution with respect to previous large-area photometric surveys in optical wavelengths. The main goal of the present work is to present the first catalog of magnitudes and colors of minor bodies of the Solar System compiled using the first data release (DR1) of the J-PLUS observational campaign: the Moving Objects Observed from Javalambre (MOOJa) catalog. Using the compiled photometric data we obtained very-low-resolution reflectance (photo)spectra of the asteroids. We first used a {sigma}-clipping algorithm in order to remove outliers and clean the data. We then devised a method to select the optimal solar colors in the J-PLUS photometric system. These solar colors were computed using two different approaches: on one hand, we used different spectra of the Sun convolved with the filter transmissions of the J-PLUS system, and on the other, we selected a group of solar-type stars in the J-PLUS DR1 according to their computed stellar parameters. Finally, we used the solar colors to obtain the reflectance spectra of the asteroids. We present photometric data in the J-PLUS filters for a total of 3122 minor bodies (3666 before outlier removal), and we discuss the main issues with the data, as well as some guidelines to solve them.
- ID:
- ivo://CDS.VizieR/J/A+A/509/A27
- Title:
- Near-Earth asteroids & QSOs close approaches
- Short Name:
- J/A+A/509/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigated the link between the International Celestial Reference Frame (ICRF) and the dynamical reference frame realized by the ephemerides of the Solar System bodies. 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 groundbased telescopes) between our selected set of asteroids and quasars with high-accuracy astrometric positions extracted from the Large Quasars Astrometric Catalog (LQAC). In the designated period (2010-2018), we found a number of 2924, 14257, and 6972 close approaches (within 10') between asteroids with a minimum solar elongation value of 60 degrees 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.
- ID:
- ivo://CDS.VizieR/J/AJ/158/196
- Title:
- Near-Earth Object Survey (MANOS) spectroscopy
- Short Name:
- J/AJ/158/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Mission Accessible Near-Earth Object Survey (MANOS) aims to observe and characterize small (mean absolute magnitude H~25 mag) Near-Earth Objects (NEOs) that are accessible by spacecraft (mean {Delta}~5.7 km/s) and that make close approaches with the Earth (mean Minimum Orbital Intersection Distance MOID ~0.03 au). We present here the first results of the MANOS visible spectroscopic survey. The spectra were obtained from August 2013 to March 2018 at Lowell Observatory's Discovery Channel 4.3 m telescope, and both Gemini North and South facilities. In total, 210 NEOs have been observed and taxonomically classified. Our taxonomic distribution shows significant variations with respect to surveys of larger objects. We suspect these to be due to a dependence of Main Belt source regions on object size. Compared to previous surveys of larger objects, we report a lower fraction of S+Q-complex asteroids of 43.8+/-4.6%. We associate this decrease with a lack of Phocaea family members at very small size. We also report higher fractions of X-complex and A-type asteroids of 23.8+/-3.3% and 3.8+/-1.3% respectively due to an increase of Hungaria family objects at small size. We find a strong correlation between the Q/S ratio and perihelion distance. We suggest this correlation is due to planetary close encounters with Venus playing a major role in turning asteroids from S to Q-type. This hypothesis is supported by a similar correlation between the Q/S ratio and Venus MOID.
- ID:
- ivo://CDS.VizieR/J/AJ/154/168
- Title:
- NEOWISE: thermal model fits for NEOs and MBAs
- Short Name:
- J/AJ/154/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Near-Earth ObjectWide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6 {mu}m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey, as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1{sigma}) of previously measured values. Diameters for the MBAs are within 17% (1{sigma}). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.
106. New asteroid models
- ID:
- ivo://CDS.VizieR/J/A+A/620/A91
- Title:
- New asteroid models
- Short Name:
- J/A+A/620/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In addition to stellar data, Gaia Data Release 2 (DR2) also contains accurate astrometry and photometry of about 14000 asteroids covering 22 months of observations. We used Gaia asteroid photometry to reconstruct rotation periods, spin axis directions, and the coarse shapes of a subset of asteroids with enough observations. One of our aims was to test the reliability of the models with respect to the number of data points and to check the consistency of these models with independent data. Another aim was to produce new asteroid models to enlarge the sample of asteroids with known spin and shape. We used the lightcurve inversion method to scan the period and pole parameter space to create final shape models that best reproduce the observed data. To search for the sidereal rotation period, we also used a simpler model of a geometrically scattering triaxial ellipsoid. By processing about 5400 asteroids with at least ten observations in DR2, we derived models for 173 asteroids, 129 of which are new. Models of the remaining asteroids were already known from the inversion of independent data, and we used them for verification and error estimation. We also compared the formally best rotation periods based on Gaia data with those derived from dense lightcurves. We show that a correct rotation period can be determined even when the number of observations N is less than 20, but the rate of false solutions is high. For N>30, the solution of the inverse problem is often successful and the parameters are likely to be correct in most cases. These results are very promising because the final Gaia catalogue should contain photometry for hundreds of thousands of asteroids, typically with several tens of data points per object, which should be sufficient for reliable spin reconstruction.
- ID:
- ivo://CDS.VizieR/J/AJ/152/221
- Title:
- New extreme trans-Neptunian objects
- Short Name:
- J/AJ/152/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We are performing a wide and deep survey for extreme distant solar system objects. Our goal is to understand the high-perihelion objects Sedna and 2012 VP113 and determine if an unknown massive planet exists in the outer solar system. The discovery of new extreme objects from our survey of some 1080 square degrees of sky to over 24th magnitude in the r-band are reported. Two of the new objects, 2014 SR349 and 2013 FT28, are extreme detached trans-Neptunian objects, which have semimajor axes greater than 150 au and perihelia well beyond Neptune (q>40au). Both new objects have orbits with arguments of perihelia within the range of the clustering of this angle seen in the other known extreme objects. One of these objects, 2014 SR349, has a longitude of perihelion similar to the other extreme objects, but 2013 FT28 is about 180{deg} away or anti-aligned in its longitude of perihelion. We also discovered the first outer Oort Cloud object with a perihelion beyond Neptune, 2014 FE72. We discuss these and other interesting objects discovered in our ongoing survey. All the high semimajor axis (a>150au) and high-perihelion (q>35au) bodies follow the previously identified argument of perihelion clustering as first reported and explained as being from an unknown massive planet in 2014 by Trujillo & Sheppard, which some have called Planet X or Planet Nine. With the discovery of 2013 FT28 on the opposite side of the sky, we now report that the argument of perihelion is significantly correlated with the longitude of perihelion and orbit pole angles for extreme objects and find there are two distinct extreme clusterings anti-aligned with each other. This previously unnoticed correlation is further evidence of an unknown massive planet on a distant eccentric inclined orbit, as extreme eccentric objects with perihelia on opposite sides of the sky (180{deg} longitude of perihelion differences) would approach the inclined planet at opposite points in their orbits, thus making the extreme objects prefer to stay away from opposite ecliptic latitudes to avoid the planet (i.e., opposite argument of perihelia or orbit pole angles).
- ID:
- ivo://CDS.VizieR/J/ApJ/758/59
- Title:
- Nickel isotopes in meteorites
- Short Name:
- J/ApJ/758/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, mass-independent, Ni isotope data for a range of bulk chondritic meteorites. The data are reported as {epsilon}g^60^Ni_58/61_, {x3b5}^62^Ni_58/61_, and {epsilon}g^64^Ni_58/61_, or the parts per ten thousand deviations from a terrestrial reference, the NIST SRM 986 standard, of the ^58^Ni/^61^Ni internally normalized ^60^Ni/^61^Ni, ^62^Ni/^61^Ni, and ^64^Ni/^61^Ni ratios. The chondrites show a range of 0.15, 0.29, and 0.84 in {epsilon}g^60^Ni_58/61_, {x3b5}^62^Ni_58/61_, and {epsilon}g^64^Ni_58/61_ relative to a typical sample precision of 0.03, 0.05, and 0.08 (2 s.e.), respectively. The carbonaceous chondrites show the largest positive anomalies, enstatite chondrites have approximately terrestrial ratios, though only EH match Earth's composition within uncertainty, and ordinary chondrites show negative anomalies. The meteorite data show a strong positive correlation between {epsilon}g^62^Ni_58/61_ and {x3b5}^64^Ni_58/61_, an extrapolation of which is within the error of the average of previous measurements of calcium-, aluminium-rich inclusions. Moreover, the slope of this bulk meteorite array is 3.003+/-0.166 which is within the error of that expected for an anomaly solely on ^58^Ni. We also determined to high precision (~10 ppm per AMU) the mass-dependent fractionation of two meteorite samples which span the range of {epsilon}g^62^Ni_58/61_ and {x3b5}^64^Ni_58/61_. These analyses show that "absolute" ratios of ^58^Ni/^61^Ni vary between these two samples whereas those of ^62^Ni/^61^Ni and ^64^Ni/^61^Ni do not. Thus, Ni isotopic differences seem most likely explained by variability in the neutron-poor ^58^Ni, and not correlated anomalies in the neutron-rich isotopes, ^62^Ni and ^64^Ni. This contrasts with previous inferences from mass-independent measurements of Ni and other transition elements which invoked variable contributions of a neutron-rich component. We have examined different nucleosynthetic environments to determine the possible source of the anomalous material responsible for the isotopic variations observed in Ni and other transition elements within bulk samples.
- ID:
- ivo://CDS.VizieR/J/AJ/135/55
- Title:
- NIR spectra of Centaurs and Kuiper Belt objects
- Short Name:
- J/AJ/135/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here an extensive survey of near-infrared (NIR) spectra of Kuiper belt objects (KBOs) and Centaurs taken with the Keck I Telescope. We find that most spectra in our sample are well characterized by a combination of water ice and a featureless continuum. A comparative analysis reveals that the NIR spectral properties have little correlation to the visible colors or albedo, with the exception of the fragment KBOs produced from the giant impact on 2003 E
- ID:
- ivo://CDS.VizieR/J/A+A/646/A182
- Title:
- Non-gravitational effects in retrograde orbits
- Short Name:
- J/A+A/646/A182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dynamical studies of asteroid populations in retrograde orbits, i.e. with orbital inclinations greater than 90 degrees, are interesting because the origin of such orbits is still unexplained. Generally, the retrograde asteroids population includes mostly Centaurs and transneptunian objects (TNOs). A special case is the Near Earth Object (343158) 2009 HC82 from the Apollo group. Another interesting object is the comet 333P/LINEAR, which for several years was considered as the second retrograde object approaching Earth. One more comet in retrograde orbit, 161P Hartley/IRAS appears to be an object of similar type. Thanks to the large amount of observational data for these two comets, we tested various models of cometary non-gravitational forces applied to their dynamics. The goal was to estimate which of non-gravitational perturbations could affect the stability of retrograde bodies. In principle, we study the local stability by measuring the divergence of nearby orbits. We have numerically determined Lyapunov chaotic indicators (LCI) and the associated Lyapunov times (LT). This time, our calculations of these parameters were extended by more advanced models of non-gravitational perturbations (i.e. Yarkovsky drift and in selected cases cometary forces). This allowed estimating the chaos in the Lyapunov sense. We found that the Yarkovsky effect for obliquities of gamma=0{deg} and gamma=180{deg} can change LT substantially. In most cases, for the prograde rotation, we received more stable solutions. Moreover, we confirmed the role of retrograde resonances in this process. Additionally, the studied cometary effects also significantly influence the long-term behaviour of the selected comets. LT can reach values from 100 to over 1000 years. All results indicate that the use of models with non-gravitational effects for retrograde bodies is clearly justified.
