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- ID:
- ivo://CDS.VizieR/J/A+A/572/A43
- Title:
- Saturnian satellites Cassini ISS astrometry
- Short Name:
- J/A+A/572/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide astrometric observations of the Saturnian satellites Mimas, Enceladus, Tethys, Dione and Rhea from Cassini Imaging Science Subsystem (ISS) narrow-angle camera (NAC) images. Image sequences were designed to observe mutual occultations between these satellites.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A76
- Title:
- Saturnian satellites in the Gaia ref. frame
- Short Name:
- J/A+A/645/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a remeasurement of old photographic plates, providing important raw data for dynamical studies of the Saturnian satellite system. The unprecedentedly accurate realization of the Gaia reference frame allows us to make a precise calibration of digitized astronegatives of the Saturnian satellite images. We reprocessed 357 astronegatives taken with the 26-inch refractor and the normal astrograph of the Pulkovo Observatory between 1972 and 2007 to obtain the positions of the main Saturnian moons in the second Gaia data release (Gaia DR2) system. Photographic plates were digitized with the Pulkovo Mobile Digitizing Device (MDD) scanner. The New Astrometric Reduction of Old Observations (NAROO) digitizer at the Paris Observatory was used to calibrate the scanned images. Satellite image centering and astrometric reduction were performed. In total, 6487 positions (equatorial coordinates) have been determined with an accuracy of 50mas. This is confirmed by a comparison of our data with modern ephemerides. The verification of the results was performed using data from past close approaches by Saturnian satellites to Gaia reference stars, showing the adequacy of the current residual analysis. A joint review of the Pulkovo and the United States Naval Observatory (USNO) intersatellite positions allows us to conclude about the existence of faint systematic effects in the satellite theories of motions at the 10mas level.
- ID:
- ivo://CDS.VizieR/J/A+A/383/296
- Title:
- Saturnian Satellites positions (1996-2000)
- Short Name:
- J/A+A/383/296
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 199 frames of CCD images of the major satellites of Saturn (Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Hyperion and Iapetus), obtained on 1-meter telescope at the Yunnan Observatory during the years of 1996-2000, are measured. These positions are compared to the ones computed with the Vienne & Duriez ephemerides (TASS1.7). The calibrated parameters of the CCD scale and orientation are determined by the comparison of their measurement coordinates with computed positions of four bright satellites of Tethy, Dione, Rhea and Titan. A catalog of 913 differential positions has been obtained. Analysis of the data as inter-satellite positions shows that these observations of the above mentioned four satellites have root-mean-square residuals of 0.04 arcsec in the sense of (O-C) (Observed minus Computed). The positional measuring procedure is proved to be good enough to obtain a small dispersion in the observations for the major Saturn satellites. The format of the present catalog are very near to the one of (Strugnell & Taylor, 1990A&AS...83..289S). The coordinates are corrected by all astrometric effects. So, these positions are really astrometric ones in that meaning that, no astrometric consideration is necessary to use them, even if one wants to touch up the calibration. Nevertheless, the raw pixels are also given in order to allow anyone to reduce again the frames.
- ID:
- ivo://CDS.VizieR/J/AJ/159/129
- Title:
- 21 saturnian small moons brightness with ISS
- Short Name:
- J/AJ/159/129
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We examine the surface brightnesses of Saturn's smaller satellites using a photometric model that explicitly accounts for their elongated shapes and thus facilitates comparisons among different moons. Analyses of Cassini imaging data with this model reveal that the moons Aegaeon, Methone, and Pallene are darker than one would expect given trends previously observed among the nearby mid-sized satellites. On the other hand, the trojan moons Calypso and Helene have substantially brighter surfaces than their co-orbital companions Tethys and Dione. These observations are inconsistent with the moons's surface brightnesses being entirely controlled by the local flux of E-ring particles, and therefore strongly imply that other phenomena are affecting their surface properties. The darkness of Aegaeon, Methone, and Pallene is correlated with the fluxes of high-energy protons, implying that high-energy radiation is responsible for darkening these small moons. Meanwhile, Prometheus and Pandora appear to be brightened by their interactions with the nearby dusty F-ring, implying that enhanced dust fluxes are most likely responsible for Calypso's and Helene's excess brightness. However, there are no obvious structures in the E-ring that would preferentially brighten these two moons, so there must either be something subtle in the E-ring particles's orbital properties that leads to asymmetries in the relevant fluxes, or something happened recently to temporarily increase these moons's brightnesses.
- ID:
- ivo://CDS.VizieR/J/A+A/621/A113
- Title:
- Saturn lightning episodes of storm F
- Short Name:
- J/A+A/621/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper analyzes a lightning storm on Saturn that raged for 7.5 months at a planetocentric latitude of 35 deg. south from 27 November 2007 until 15 July 2008. The storm system produced about 277000 lightning events termed SEDs (for Saturn Electrostatic Discharges) that were detected by the Cassini RPWS (Radio and Plasma Wave Science) instrument. The SEDs are organized in episodes, lasting typically for half a Saturn rotation. SEDs can be detected when the observer Cassini is within the radio horizon (usually when the storm and Cassini are on the same side of the planet), and they are not detected when Cassini is beyond the radio horizon (Cassini and the storm on opposite sides). Saturn's atmospheric storm features have a much higher angular velocity than Cassini around Saturn, so that one SED episode is typically related to one Saturn rotation. The SEDs from this storm, lasting from the end of Nov. 2007 until mid-July 2008 (termed storm F), occurred in 439 SED episodes.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/67
- Title:
- Saturn's G and D68 rings ISS observations
- Short Name:
- J/ApJ/811/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The appearance of debris disks around distant stars depends upon the scattering/phase function (SPF) of the material in the disk. However, characterizing the SPFs of these extrasolar debris disks is challenging because only a limited range of scattering angles are visible to Earth-based observers. By contrast, Saturn's tenuous rings can be observed over a much broader range of geometries, so their SPFs can be much better constrained. Since these rings are composed of small particles released from the surfaces of larger bodies, they are reasonable analogs to debris disks and so their SPFs can provide insights into the plausible scattering properties of debris disks. This work examines two of Saturn's dusty rings: the G ring (at 167500km from Saturn's center) and the D68 ringlet (at 67600km). Using data from the cameras on board the Cassini spacecraft, we are able to estimate the rings' brightnesses at scattering angles ranging from 170{deg} to 0.5{deg}. We find that both of the rings exhibit extremely strong forward-scattering peaks, but for scattering angles above 60{deg} their brightnesses are nearly constant. These SPFs can be well approximated by a linear combination of three Henyey-Greenstein functions, and are roughly consistent with the SPFs of irregular particles from laboratory measurements. Comparing these data to Fraunhofer and Mie models highlights several challenges involved in extracting information about particle compositions and size distributions from SPFs alone. The SPFs of these rings also indicate that the degree of forward scattering in debris disks may be greatly underestimated.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A54
- Title:
- SBNAF Infrared Database
- Short Name:
- J/A+A/635/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the Small Bodies: Near and Far (SBNAF) Infrared Database, an easy-to-use tool intended to facilitate the modelling of thermal emission of small bodies of the Solar System. Our database collects measurements of thermal emissions for small Solar System targets that are otherwise available in scattered sources and provides a complete description of the data, including all information necessary to perform direct scientific analyses and without the need to access additional external resources. This public database contains representative data of asteroid observations of large surveys (e.g. AKARI, IRAS, and WISE) as well as a collection of small body observations of infrared space telescopes (e.g. the Herschel Space Observatory) and provides a web interface to access this data (https://ird.konkoly.hu).We also provide an example for the direct application of the database and show how it can be used to estimate the thermal inertia of specific populations, e.g. asteroids within a given size range. We show how different scalings of thermal inertia with heliocentric distance (i.e. temperature) may affect our interpretation of the data and discuss why the widely-used radiative conductivity exponent (alpha=-3/4) might not be adequate in general, as suggested in previous studies.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A59
- Title:
- SDSS Solar System Objects
- Short Name:
- J/A+A/652/A59
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The populations of small bodies of the Solar System (asteroids, comets, Kuiper-Belt objects) are used to constrain the origin and evolution of the Solar System. Both their orbital distribution and composition distribution are required to track the dynamical pathway from their regions of formation to their current locations. We aim at increasing the sample of Solar System objects that have multi-filter photometry and compositional taxonomy. We search for moving objects in the archive of the Sloan Digital Sky Survey. We attempt at maximizing the number of detections by using loose constraints on the extraction. We then apply a suite of filters to remove false-positive detections (stars or galaxies) and mark out spurious photometry and astrometry. We release a catalog of 1542522 entries, consisting of 1036322 observations of 379714 known and unique SSOs together with 506200 observations of moving sources not linked with any known SSOs. The catalog completeness is estimated to be about 95% and the purity to be above 95% for known SSOs.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/66
- Title:
- Search for extraterrestrial intelligence with ATA
- Short Name:
- J/ApJ/869/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a novel radio autocorrelation search for extraterrestrial intelligence. For selected frequencies across the terrestrial microwave window (1-10GHz), observations were conducted at the Allen Telescope Array to identify artificial non-sinusoidal periodic signals with radio bandwidths greater than 4Hz, which are capable of carrying substantial messages with symbol rates from 4 to 10^6^Hz. Out of 243 observations, about half (101) were directed toward sources with known continuum flux >~1Jy over the sampled bandwidth (quasars, pulsars, supernova remnants, and masers), based on the hypothesis that they might harbor heretofore undiscovered natural or artificial repetitive, phase or frequency modulation. The rest of the observations were directed mostly toward exoplanet stars with no previously discovered continuum flux. No signals attributable to extraterrestrial technology were found in this study. We conclude that the maximum probability that future observations like the ones described here will reveal repetitively modulated emissions is less than 5% for continuum sources and exoplanets alike. The paper concludes by describing a new approach to expanding this survey to many more targets and much greater sensitivity using archived data from interferometers all over the world.
