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1051. Asteroidal I, J, K in the DENIS Survey
ID:
ivo://CDS.VizieR/J/A+A/423/381
Title:
Asteroidal I, J, K in the DENIS Survey
Short Name:
J/A+A/423/381
Date:
21 Oct 2021
Publisher:
CDS
Description:
I, J, K magnitudes of 767 asteroids (numbered between 1 and 8000) are presented here. These asteroids have been recovered in the DENIS Survey (Deep European Near-Infrared southern sky Survey) on the basis of their predicted ephemerides. The observations were performed with the 1m-telescope at ESO, La Silla (Chile). The limiting magnitudes of the three bands I, J, K centered at 0.8, 1.25 and 2.15 microns are respectively 18.5, 16.5 and 13.5.
1052. Asteroid (31) Euphrosyne R-band images
ID:
ivo://CDS.VizieR/J/A+A/641/A80
Title:
Asteroid (31) Euphrosyne R-band images
Short Name:
J/A+A/641/A80
Date:
21 Oct 2021
Publisher:
CDS
Description:
Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and it is also the largest member of its namesake family. The Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event.The goals of this adaptive-optics imaging study are threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at the ESO 8.2m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D shape via the ADAM shape modeling algorithm based on the SPHERE images and the available light curves of this asteroid. We analyzed the dynamics of the satellite with the \genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne's diameter is 268+/-6km, making it one of the top ten largest main belt asteroids. We detected a satellite of Euphrosyne - S/2019 (31) 1 - that is about 4 km across, on a circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665+/-242kg/m^-3^, suggesting that Euphrosyne probably contains a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10)Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from those suggested by fluid hydrostatic equilibrium following reaccumulation.
1053. Asteroid (7) Iris Deconvolved disk-resolved images
ID:
ivo://CDS.VizieR/J/A+A/624/A121
Title:
Asteroid (7) Iris Deconvolved disk-resolved images
Short Name:
J/A+A/624/A121
Date:
21 Oct 2021
Publisher:
CDS
Description:
Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V~7-8) and large angular size of 0.33'' during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100Myr of the solar system's collisional evolution. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE and earlier AO systems as inputs. We analyzed the SPHERE images and our model to infer the asteroid's global shape and the morphology of its main craters. Results. We present the 3D shape, volume-equivalent diameter D_eq_=214+/-5km, and bulk density {rho}=2.7+/-0.3g/cm^3^ of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20-40km in diameter detected at several epochs, which we interpret as impact craters, and several additional crater candidates. Craters on Iris have depth-to-diameter ratios that are similar to those of analogous 10km craters on Vesta. The bulk density of Iris is consistent with that of its meteoritic analog based on spectroscopic observations, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3Gyr) impact. Iris's shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities, and the absence of a substantial impact-induced regolith on Iris.
1054. Asteroid positions in 2002
ID:
ivo://CDS.VizieR/J/other/CoSka/33.159
Title:
Asteroid positions in 2002
Short Name:
J/other/CoSka/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
The paper presents the results of position determinations of minor planets carried out at the Skalnate Pleso Observatory in the year 2002. 109 CCD observations of 21 minor planets are given together with the list of reference stars.
1055. 2728 asteroid positions (Kitab obs.)
ID:
ivo://CDS.VizieR/J/other/OAP/31.235
Title:
2728 asteroid positions (Kitab obs.)
Short Name:
J/other/OAP/31.2
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photographic observations of XX century contained numerous and varied information about all objects and events of the Universe fixed on the astronegatives. The original and interesting observations of small bodies of the Solar system in previous years can be selected and used for various scientific tasks. Existing databases and online services can help make such selection easily and quickly. The observations of chronologically earlier oppositions, photometric evaluation of brightness for long periods of time allow refining the orbits of asteroids and identifying various non-stationarities. Photographic observations of the Northern Sky Survey project (FON project) were used for global search for small bodies of Solar system. About 2000 photographic plates of Kitab part of the FON project were made using Double Wide Angle Astrograph at the Kitab observatory (Uzbekistan) during 1981-1989. Early, using that digitized observations the catalogue of equatorial coordinates and stellar magnitudes for more than 13 million stars and galaxies up to B=17.5m was compiled. At present, we analyzed all processing results for the search of asteroids and compiled the catalogue of equatorial coordinates and stellar magnitudes of them. As a result more than 4500 asteroids and comets with visual magnitude from 7.7m to 17.5m were identified now. All positions of asteroids were compared with ephemeris. A preliminary analysis of O-C differences was carried out. New and interesting are that the moments of official discovery of some identified asteroids much later than their moments of Kitab's observation. In addition, some of them are the earliest observations of these asteroids in the world among all known observations. More than 915 observations of such asteroids have been found on the plates of Kitab part of the FON project.
1056. Asteroids in GALEX
ID:
ivo://CDS.VizieR/J/ApJ/809/92
Title:
Asteroids in GALEX
Short Name:
J/ApJ/809/92
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ultraviolet (UV) photometry (near-UV (NUV) band, 180-280nm) of 405 asteroids observed serendipitously by GALEX from 2003 to 2012. All asteroids in this sample were detected by GALEX at least twice. Unambiguous visible-color-based taxonomic labels (C type versus S type) exist for 315 of these asteroids; of these, thermal-infrared-based diameters are available for 245. We derive NUV-V color using two independent models to predict the visual magnitude V at each NUV-detection epoch. Both V models produce NUV-V distributions in which the S types are redder than C types with more than 8{sigma} confidence. This confirms that the S types' redder spectral slopes in the visible remain redder than the C types' into the NUV, this redness being consistent with absorption by silica-containing rocks. The GALEX asteroid data confirm earlier results from the International Ultraviolet Explorer, which two decades ago produced the only other sizeable set of UV asteroid photometry. The GALEX-derived NUV-V data also agree with previously published Hubble Space Telescope (HST) UV observations of asteroids 21 Lutetia and 1 Ceres. Both the HST and GALEX data indicate that NUV band is less useful than u band for distinguishing subgroups within the greater population of visible-color-defined C types (notably, M types and G types).
1057. Asteroseismic analysis of 8 Kepler red giants
ID:
ivo://CDS.VizieR/J/ApJ/838/115
Title:
Asteroseismic analysis of 8 Kepler red giants
Short Name:
J/ApJ/838/115
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using data from the NASA spacecraft Kepler, we study solar-like oscillations in red giant stars in the open cluster NGC 6811. We determine oscillation frequencies, frequency separations, period spacings of mixed modes, and mode visibilities for eight cluster giants. The oscillation parameters show that these stars are helium-core-burning red giants. The eight stars form two groups with very different oscillation power spectra; the four stars with the lowest {Delta}{nu} values display rich sets of mixed l=1 modes, while this is not the case for the four stars with higher {Delta}{nu}. For the four stars with lowest {Delta}{nu}, we determine the asymptotic period spacing of the mixed modes, {Delta}P, which together with the masses we derive for all eight stars suggest that they belong to the so-called secondary clump. Based on the global oscillation parameters, we present initial theoretical stellar modeling that indicates that we can constrain convective-core overshoot on the main sequence and in the helium-burning phase for these ~2M_{sun}_ stars. Finally, our results indicate less mode suppression than predicted by recent theories for magnetic suppression of certain oscillation modes in red giants.
1058. Asteroseismic analysis of 22 solar-type stars
ID:
ivo://CDS.VizieR/J/ApJ/749/152
Title:
Asteroseismic analysis of 22 solar-type stars
Short Name:
J/ApJ/749/152
Date:
21 Oct 2021
Publisher:
CDS
Description:
Asteroseismology with the Kepler space telescope is providing not only an improved characterization of exoplanets and their host stars, but also a new window on stellar structure and evolution for the large sample of solar-type stars in the field. We perform a uniform analysis of 22 of the brightest asteroseismic targets with the highest signal-to-noise ratio observed for 1 month each during the first year of the mission, and we quantify the precision and relative accuracy of asteroseismic determinations of the stellar radius, mass, and age that are possible using various methods. We present the properties of each star in the sample derived from an automated analysis of the individual oscillation frequencies and other observational constraints using the Asteroseismic Modeling Portal (AMP), and we compare them to the results of model-grid-based methods that fit the global oscillation properties. We find that fitting the individual frequencies typically yields asteroseismic radii and masses to ~1% precision, and ages to ~2.5% precision (respectively, 2, 5, and 8 times better than fitting the global oscillation properties). The absolute level of agreement between the results from different approaches is also encouraging, with model-grid-based methods yielding slightly smaller estimates of the radius and mass and slightly older values for the stellar age relative to AMP, which computes a large number of dedicated models for each star. The sample of targets for which this type of analysis is possible will grow as longer data sets are obtained during the remainder of the mission.
1059. Asteroseismic classification of KIC objects
ID:
ivo://CDS.VizieR/J/ApJ/765/L41
Title:
Asteroseismic classification of KIC objects
Short Name:
J/ApJ/765/L41
Date:
21 Oct 2021
Publisher:
CDS
Description:
Of the more than 150000 targets followed by the Kepler Mission, about 10% were selected as red giants. Due to their high scientific value, in particular for Galaxy population studies and stellar structure and evolution, their Kepler light curves were made public in late 2011. More than 13000 (over 85%) of these stars show intrinsic flux variability caused by solar-like oscillations making them ideal for large-scale asteroseismic investigations. We automatically extracted individual frequencies and measured the period spacings of the dipole modes in nearly every red giant. These measurements naturally classify the stars into various populations, such as the red giant branch, the low-mass (M/M_{sun}_<~1.8) helium-core-burning red clump, and the higher-mass (M/M_{sun}_>~1.8) secondary clump. The period spacings also reveal that a large fraction of the stars show rotationally induced frequency splittings. This sample of stars will undoubtedly provide an extremely valuable source for studying the stellar population in the direction of the Kepler field, in particular when combined with complementary spectroscopic surveys.
1060. Asteroseismic parameters of RGB stars
ID:
ivo://CDS.VizieR/J/AJ/158/227
Title:
Asteroseismic parameters of RGB stars
Short Name:
J/AJ/158/227
Date:
21 Oct 2021
Publisher:
CDS
Description:
Every Sun-like star will eventually evolve into a red giant, a transition which can profoundly affect the evolution of a surrounding planetary system. The timescale of dynamical planet evolution and orbital decay has important implications for planetary habitability, as well as post-main-sequence star and planet interaction, evolution, and internal structure. Here, we investigate these effects by estimating planet occurrence around 2476 low-luminosity red giant branch (LLRGB) stars observed by the NASA K2 mission. We measure stellar masses and radii using asteroseismology, with median random uncertainties of 3.7% in mass and 2.2% in radius. We compare this planet population to the known population of planets around dwarf Sun-like stars, accounting for detection efficiency differences between the stellar populations. We find that 0.49%+/-0.28% of LLRGB stars host planets larger than Jupiter with orbital periods less than 10 days, tentatively higher than main-sequence stars hosting similar planets (0.15%+/-0.06%). Our results suggest that the effects of stellar evolution on the occurrence of close-in planets larger than Jupiter are not significant until stars have begun ascending substantially up the red giant branch (>~5-6 R_{sun}_).

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