- ID:
- ivo://CDS.VizieR/J/AJ/157/139
- Title:
- Inner Oort cloud survey observations: 2015 TG387
- Short Name:
- J/AJ/157/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Inner Oort cloud objects (IOCs) are trans-Plutonian for their entire orbits. They are beyond the strong gravitational influences of the known planets, yet close enough to the Sun that outside forces are minimal. Here we report the discovery of the third known IOC after Sedna and 2012 VP113, called 2015 TG387. This object has a perihelion of 65+/-1 au and semimajor axis of 1170+/-70 au. The longitude of perihelion angle, {omega}, for 2015 TG387 is between that of Sedna and 2012 VP113 and thus similar to the main group of clustered extreme trans-Neptunian objects (ETNOs), which may be shepherded into similar orbital angles by an unknown massive distant planet called Planet X, or Planet Nine. The orbit of 2015 TG387 is stable over the age of the solar system from the known planets and Galactic tide. When including outside stellar encounters over 4 Gyr, 2015 TG387's orbit is usually stable, but its dynamical evolution depends on the stellar encounter scenarios used. Surprisingly, when including a massive Planet X beyond a few hundred au on an eccentric orbit that is antialigned in longitude of perihelion with most of the known ETNOs, we find that 2015 TG387 is typically stable for Planet X orbits that render the other ETNOs stable as well. Notably, 2015 TG387's argument of perihelion is constrained, and its longitude of perihelion librates about 180{deg} from Planet X's longitude of perihelion, keeping 2015 TG387 antialigned with Planet X over the age of the solar system.
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- ID:
- ivo://CDS.VizieR/J/A+A/633/A65
- Title:
- (704) Interamnia images
- Short Name:
- J/A+A/633/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With an estimated diameter in the 320 to 350km range, (704) Interamnia is the fifth largest main belt asteroid and one of the few bodies that fills the gap in size between the four largest bodies with D>400km (Ceres, Vesta, Pallas and Hygiea) and the numerous smaller bodies with diameter 200 km. However, despite its large size, little is known about the shape and spin state of Interamnia and, therefore, about its bulk composition and past collisional evolution. We aimed to test at what size and mass the shape of a small body departs from a nearly ellipsoidal equilibrium shape (as observed in the case of the four largest asteroids) to an irregular shape as routinely observed in the case of smaller (D<=200km) bodies. We observed Interamnia as part of our ESO VLT/SPHERE large program (ID: 199.C-0074) at thirteen different epochs. In addition, several new optical lightcurves were recorded. These data, along with stellar occultation data from the literature, were fed to the All-Data Asteroid Modeling (ADAM) algorithm to reconstruct the 3D-shape model of Interamnia and to determine its spin state. Interamnia's volume-equivalent diameter of 332+/-6km implies a bulk density of {rho}=1.98+/-0.68g/cm^3^, which suggests that Interamnia - like Ceres and Hygiea - contains a high fraction of water ice, consistent with the paucity of apparent craters. Our observations reveal a shape that can be well approximated by an ellipsoid, and that is compatible with a fluid hydrostatic equilibrium at the 2{sigma}level. The rather regular shape of Interamnia implies that the size and mass limit, under which the shapes of minor bodies with a high amount of water ice in the subsurface become irregular, has to be searched among smaller (D<=300km) less massive (m<=3x10^19^kg) bodies.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A143
- Title:
- Ion and femtosecond laser irradiation spectra
- Short Name:
- J/A+A/654/A143
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Space weathering is a process that changes the surface of airless planetary bodies. Prime space weathering agents are solar wind irradiation and micrometeoroid bombardment. These processes alter planetary reflectance spectra and often modify their compositional diagnostic features. In this work we focused on simulating and comparing the spectral changes caused by solar wind irradiation and by micrometeoroid bombardment to gain a better understanding of these individual space weathering processes. We used olivine and pyroxene pellets as proxies for planetary materials. To simulate solar wind irradiation we used hydrogen, helium, and argon ions with energies from 5 to 40keV and fluences of up to 10^18^particles/cm^2^. To simulate micrometeoroid bombardment we used individual femtosecond laser pulses. We analysed the corresponding evolution of different spectral parameters, which we determined by applying the Modified Gaussian Model, and we also conducted principal component analysis. The original mineralogy of the surface influences the spectral evolution more than the weathering agent, as seen from the diverse evolution of the spectral slope of olivine and pyroxene upon irradiation. The spectral slope changes seen in olivine are consistent with observations of A-type asteroids, while the moderate to no slope changes observed in pyroxene are consistent with asteroid (4) Vesta. We also observed some differences in the spectral effects induced by the two weathering agents. Ions simulating solar wind have a smaller influence on longer wavelengths of the spectra than laser irradiation simulating micrometeoroid impacts. This is most likely due to the different penetration depths of ions and laser pulses. Our results suggest that in some instances it might be possible to distinguish between the contributions of the two agents on a weathered surface.
- 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.
- 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.
