- ID:
- ivo://CDS.VizieR/J/AJ/158/29
- Title:
- Io's hot spots NIR adaptive optics: 2013-2018
- Short Name:
- J/AJ/158/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present measurements of the near-infrared brightness of Io's hot spots derived from 2 to 5 {mu}m imaging with adaptive optics on the Keck and Gemini N telescopes. The data were obtained on 271 nights between 2013 August and the end of 2018, and include nearly 1000 detections of over 75 unique hot spots. The 100 observations obtained between 2013 and 2015 have been previously published in de Kleer & de Pater (2016Icar..280..378D) the observations since the start of 2016 are presented here for the first time, and the analysis is updated to include the full five-year data set. These data provide insight into the global properties of Io's volcanism. Several new hot spots and bright eruptions have been detected, and the preference for bright eruptions to occur on Io's trailing hemisphere noted in the 2013-2015 data is strengthened by the larger data set and remains unexplained. The program overlapped in time with Sprint-A/EXCEED and Juno observations of the Jovian system, and correlations with transient phenomena seen in other components of the system have the potential to inform our understanding of the impact of Io's volcanism on Jupiter and its neutral/plasma environment.
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- ID:
- ivo://CDS.VizieR/J/AJ/155/184
- Title:
- Irregular planetary satellites colors & shapes
- Short Name:
- J/AJ/155/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is widely recognized that the irregular satellites of the giant planets were captured from initially heliocentric orbits. However, the mechanism of capture and the source region from which they were captured both remain unknown. We present an optical color survey of 43 irregular satellites of the outer planets conducted using the LRIS camera on the 10 m telescope at the Keck Observatory in Hawaii. The measured colors are compared to other planetary bodies in search for similarities and differences that may reflect upon the origin of the satellites. We find that ultrared matter (with color index B-R>=1.6), while abundant in the Kuiper Belt and Centaur populations, is depleted from the irregular satellites. We also use repeated determinations of the absolute magnitudes to make a statistical estimate of the average shape of the irregular satellites. The data provide no evidence that the satellites and the main-belt asteroids are differently shaped, consistent with collisions as the major agent shaping both.
- ID:
- ivo://CDS.VizieR/J/AJ/123/2070
- Title:
- ISO deep asteroid search
- Short Name:
- J/AJ/123/2070
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of six deep exposures (using the astronomical observation template CAM01 with a 6" pixel field of view) through the ISOCAM LW10 filter (IRAS band 1, i.e., 12{mu}m) were obtained on a ~15' square field centered on the ecliptic plane. Point sources were extracted using the technique described in 1999 by Deert et al. Twoknown asteroids appear in these frames, and 20 sources moving with velocities appropriate for main-belt asteroids are present. Most of the asteroids detected have flux densities less than 1 mJy, that is, between 150 and 350 times fainter than any of the asteroids observed by IRAS. These data provide the first direct measurement of the 12{mu}m sky-plane density for asteroids on the ecliptic equator. The median zodiacal foreground, as measured by ISOCAM during this survey, is found to be 22.1+/-1.5mJy/pixel, i.e. 26.2+/-1.7MJy/sr. The results presented here imply that the actual number of kilometer-sized asteroids may be higher than several recent estimates based upon observations at visual wavelengths and are in reasonable agreement with the statistical asteroid model. Using results from the observations presented here, together with three other recent population estimates, we conclude that the cumulative number of main-belt asteroids with diameters greater than 1km is (1.2+/-0.5)x10^6^.
- ID:
- ivo://CDS.VizieR/J/ApJ/758/45
- Title:
- Isotopic Sr abundances in meteorites
- Short Name:
- J/ApJ/758/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived ^87^Rb-^87^Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial ^87^Sr/^86^Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in ^84^Sr/^86^Sr between calcium aluminum inclusions and eucrites ({epsilon}g^84^Sr>2), the difference in age between these materials would be ~6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U-Pb and Mn-Cr.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A17
- Title:
- Jupiter decametric radio emissions over 26 years
- Short Name:
- J/A+A/604/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Jupiter is a complex and at the same time very powerful radio source in the decameter wavelength range. The emission is anisotropic, intrinsically variable at millisecond to hour timescales, and also modulated by various external processes at much longer periods, ranging from ~10h to months or years (including Jovian day and year, solar activity and solar wind variations, and for ground-based observations, terrestrial day and year). As a consequence, long-term observations and their statistical study have proved to be necessary for disentangling and understanding the observed phenomena. We have built a database from the available 26yr of systematic, daily observations conducted at the Nancay Decameter Array and recorded in digital format. This database contains all observed Jovian decametric emissions, classified with respect to the time-frequency morphology, their dominant circular polarization, and maximum frequency. We present the results of the first statistical analysis of this database. We confirm the earlier classification of Jovian decameter emissions in Io-A, -A', -B, -C, -D and non-Io-A, -B, -C types, but we also introduce new emission types (Io-A'' and Io-B') and precise and characterize the non-Io-D type. We determine the contours of all emission types in the CML-{Phi}_Io_ plane (Central Meridian Longitude in Jupiter's System III coordinates versus Io Phase), provide representative examples of their typical time-frequency patterns, and the distribution of emission's maximum frequency as a function of {LAMBDA}_Io_ (Io's Longitude). Finally, we present a statistical analysis of the distributions of the occurrence rate, duration, intensity and polarization for each emission type. non-Io-DAM appears to be related to small-scale, possibly bursty auroral structures.
- ID:
- ivo://CDS.VizieR/J/A+A/610/A21
- Title:
- KiDS Survey for solar system objects mining
- Short Name:
- J/A+A/610/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The search for minor bodies in the Solar System promises insights into its formation history. Wide imaging surveys offer the opportunity to serendipitously discover and identify these traces of planetary formation and evolution. We present a method to acquire position, photometry, and proper motion measurements of Solar System objects in surveys using dithered image sequences. The application of this method on the Kilo-Degree Survey is demonstrated. Optical images of 346deg^2^ fields of the sky are searched in up to four filters using the AstrOmatic software suite to reduce the pixel to catalog data. The Solar System objects within the acquired sources are selected based on a set of criteria depending on their number of observation, motion, and size. The Virtual Observatory SkyBoT tool is used to identify known objects. We observed 20,221 SSO candidates, with an estimated false-positive content of less than 0.05%. Of these SSO candidates, 53.4% are identified by SkyBoT. KiDS can detect previously unknown SSOs because of its depth and coverage at high ecliptic latitude, including parts of the Southern Hemisphere. Thus we expect the large fraction of the 46.6% of unidentified objects to be truly new SSOs. Our method is applicable to a variety of dithered surveys such as DES, LSST, and Euclid. It offers a quick and easy-to-implement search for Solar System objects. SkyBoT can then be used to estimate the completeness of the recovered sample.
- ID:
- ivo://CDS.VizieR/J/A+A/653/A57
- Title:
- (216) Kleopatra images
- Short Name:
- J/A+A/653/A57
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The recent estimates of the 3D shape of the M/Xe-type triple asteroid system (216) Kleopatra indicated a density of ~5g/cm^3^, which is by far the highest for a small Solar System body. Such a high density implies a high metal content as well as a low porosity which is not easy to reconcile with its peculiar "dumbbell" shape. Given the unprecedented angular resolution of the VLT/SPHERE/ZIMPOL camera, here, we aim to constrain the mass (via the characterization of the orbits of the moons) and the shape of (216) Kleopatra with high accuracy, hence its density. We combined our new VLT/SPHERE observations of (216) Kleopatra recorded during two apparitions in 2017 and 2018 with archival data from the W.M. Keck Observatory, as well as lightcurve, occultation, and delay-Doppler images, to derive a model of its 3D shape using two different algorithms (ADAM, MPCD). Furthermore, an N-body dynamical model allowed us to retrieve the orbital elements of the two moons as explained in the accompanying paper. The shape of (216) Kleopatra is very close to an equilibrium dumbbell figure with two lobes and a thick neck. Its volume equivalent diameter (118.75+/-1.40)km and mass (2.97+/-0.32)*10^18^kg (i.e., 56% lower than previously reported) imply a bulk density of (3.38+/-0.50)g/cm^3^. Such a low density for a supposedly metal-rich body indicates a substantial porosity within the primary. This porous structure along with its near equilibrium shape is compatible with a formation scenario including a giant impact followed by reaccumulation. (216) Kleopatra's current rotation period and dumbbell shape imply that it is in a critically rotating state. The low effective gravity along the equator of the body, together with the equatorial orbits of the moons and possibly rubble-pile structure, opens the possibility that the moons formed via mass shedding.
- ID:
- ivo://CDS.VizieR/J/AJ/154/162
- Title:
- KMTNet-SAAO observation of near-Earth asteroids
- Short Name:
- J/AJ/154/162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here VRI spectrophotometry of 39 near-Earth asteroids (NEAs) observed with the Sutherland, South Africa, node of the Korea Microlensing Telescope Network (KMTNet). Of the 39 NEAs, 19 were targeted, but because of KMTNet's large 2{deg}x2{deg} field of view, 20 serendipitous NEAs were also captured in the observing fields. Targeted observations were performed within 44 days (median: 16 days, min: 4 days) of each NEA's discovery date. Our broadband spectrophotometry is reliable enough to distinguish among four asteroid taxonomies and we were able to confidently categorize 31 of the 39 observed targets as either an S-, C-, X-, or D-type asteroid by means of a Machine Learning algorithm approach. Our data suggest that the ratio between "stony" S-type NEAs and "not-stony" (C+X+D)-type NEAs, with H magnitudes between 15 and 25, is roughly 1:1. Additionally, we report ~1 hr light curve data for each NEA, and of the 39 targets, we were able to resolve the complete rotation period and amplitude for six targets and report lower limits for the remaining targets.
- ID:
- ivo://CDS.VizieR/J/A+A/532/A89
- Title:
- La2010: orbital solution for long term Earth motion
- Short Name:
- J/A+A/532/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here a new solution for the astronomical computation of the orbital motion of the Earth spanning from 0 to -250Myr. The main improvement with respect to our previous numerical solution La2004 is an improved adjustment of the parameters and initial conditions through a fit over 1Myr to a special version of the highly accurate numerical ephemeris INPOP08 (Integration Numerique Planetaire de l'Observatoire de Paris). The precession equations have also been entirely revised and are no longer averaged over the orbital motion of the Earth and Moon. This new orbital solution is now valid over more than 50Myr in the past or into the future with proper phases of the eccentricity variations. Owing to the chaotic behavior, the precision of the solution decreases rapidly beyond this time span, and we discuss the behavior of various solutions beyond 50Myr. For paleoclimate calibrations, we provide several different solutions that are all compatible with the most precise planetary ephemeris. We have thus reached the time where geological data are now required to discriminate between planetary orbital solutions beyond 50Myr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/4634
- Title:
- Large perihelion dist. Oort spike comets
- Short Name:
- J/MNRAS/472/4634
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The complete sample of large-perihelion nearly-parabolic comets discovered during the period 1901-2010 is studied, starting with their orbit determination. Next, an orbital evolution that includes three perihelion passages (previous-observed-next) is investigated in which a full model of Galactic perturbations and perturbations from passing stars is incorporated. We show that the distribution of planetary perturbations suffered by actual large-perihelion comets during their passage through the Solar system has a deep, unexpected minimum around zero, which indicates a lack of 'almost unperturbed' comets. Using a series of simulations we show that this deep well is moderately resistant to some diffusion of the orbital elements of the analysed comets. It seems reasonable to assert that the observed stream of these large perihelion comets experienced a series of specific planetary configurations when passing through the planetary zone. An analysis of the past dynamics of these comets clearly shows that dynamically new comets can appear only when their original semimajor axes are greater than 20000au. On the other hand, dynamically old comets are completely absent for semimajor axes longer than 40000au. We demonstrate that the observed 1/a_ori_-distribution exhibits a local minimum separating dynamically new from dynamically old comets. Long-term dynamical studies reveal a wide variety of orbital behaviour. Several interesting examples of the action of passing stars are also described, in particular the impact of Gliese 710, which will pass close to the Sun in the future. However, none of the obtained stellar perturbations is sufficient to change the dynamical status of the analysed comets.
