- ID:
- ivo://CDS.VizieR/J/A+A/468/L13
- Title:
- Photometry of the trans-Neptunian object 2005FY9
- Short Name:
- J/A+A/468/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The goal of this work is the study of 2005FY_9's short term variability in order to determine the amplitude of the lightcurve, which can be linked to the degree of elongation of the body or to the degree of albedo heterogeneity on the surface. Besides, the rotation period can be determined. CCD photometric observations of the transneptunian object 2005FY_9 in R band on 21 nights spanning several months have been carried out using the 1.5m telescope at Sierra Nevada Observatory and the 2.2m telescope at Calar Alto Observatory. The time series analysis results in confident detection of short-term variability. The most significant periodicities are 11.24+/-0.01h and its double, but other possibilities cannot be ruled out. The 22.48h double peaked rotational phase curve is slightly preferred from our analysis. As for the amplitude of the lightcurve, we get a peak to peak variability of 0.03+/-0.01mag. This result is compatible with a nearly spherical body that has a very homogeneous surface. There is also the possibility that the body is rotating nearly pole on, but we believe this is less likely. Very weak constraints are obtained for the density and internal strength based on the rotational properties derived from the photometry.
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- ID:
- ivo://CDS.VizieR/J/A+A/570/A86
- Title:
- Pluto astrometry from 19yrs observations
- Short Name:
- J/A+A/570/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present astrometric positions of Pluto, consistent with the International Celestial Reference System, from 4412 CCD frames observed over 120 nights with three telescopes at the Observatorio do Pico dos Dias in Brazil, covering a time span from 1995 to 2013, and also 145 frames observed over 11 nights in 2007 and 2009 with the ESO/MPG 2.2m telescope equipped with the Wide Field Imager (WFI). Our aim is to contribute to the study and improvement of the orbit of Pluto with new astrometric methods and positions.
- ID:
- ivo://CDS.VizieR/J/A+A/553/A14
- Title:
- Pluto's observations between 1997 and 2010
- Short Name:
- J/A+A/553/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Because of Pluto's distance from the Sun, the Pluto system has not yet completed a revolution since its discovery, hence an uncertain heliocentric distance. In this paper, we present the fitting of our dynamical model ODIN (Orbite, Dynamique et Integration Numerique) to observations. The small satellites P4 and P5 are not taken into account. We fitted our model to the measured absolute coordinates (RA, DEC) of Pluto, and to the measured positions of the satellites relative to Pluto.
- ID:
- ivo://CDS.VizieR/J/A+A/529/A86
- Title:
- Polarimetric survey of main-belt asteroids
- Short Name:
- J/A+A/529/A86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a polarimetric survey of main-belt asteroids at Complejo Astronomico El Leoncito (Casleo), San Juan, Argentina. The aims of this survey are to increase the database of asteroid polarimetry, to estimate diversity in polarimetric properties of asteroids that belong to different taxonomic classes, and to search for objects that exhibit anomalous polarimetric properties, similar to those shown by the asteroid (234) Barbara. The data were obtained with the Torino and CASPROF polarimeters at the 2.15m telescope. The Torino polarimeter is an instrument that allows the simultaneous measurement of polarization in five different bands, and the CASPROF polarimeter is a two-hole aperture polarimeter with rapid modulation.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/L33
- Title:
- Polarimetric survey of Phaethon with PICO
- Short Name:
- J/ApJ/864/L33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a function of the solar phase angle, {alpha}, the linear polarization degree (referred to the scattering plane, P_r_) of solar system objects is a good diagnostic for understanding the scattering properties of their surface materials. We report the P_r_ of Phaethon over a wide range of {alpha} from 19.1{deg} to 114.3{deg}. The derived phase-polarization curve shows that the maximum of P_r_, Pmax, is >42.4% at {alpha}>114.3{deg}, a value significantly larger than those of the moderate albedo asteroids (Pmax~9%). The phase-polarization curve classifies Phaethon as B-type as well as M- and K-type asteroids, in the polarimetric taxonomy, being compatible with the spectral property. We compute the geometric albedo, p_v_, of 0.14+/-0.04 independently by using an empirical slope-albedo relation, and the derived p_v_ is consistent with previous results determined from mid-infrared spectra and thermophysical modeling. We find no periodic variation of P_r_ in our polarimetric data in the range from 0 up to 7.208hr (e.g., less than twice the rotational period). We also find significant differences between our P_r_ during the 2017 approach toward Earth and that in 2016, implying that Phaethon has a region with different properties for light scattering near its rotational pole.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A42
- Title:
- Polarimetry of Main-Belt Asteroids
- Short Name:
- J/A+A/626/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a polarimetric survey of main-belt asteroids at Complejo Astronomico El Leoncito (CASLEO), San Juan, Argentina. The aims of this survey are to increase the database of asteroid polarimetry and to estimate the diversity in the polarimetric properties of asteroids. The survey began in 1995 and a second period began in 2013 using the CASPOL polarimeter with a more sensitive detector to study small asteroids, families, and special taxonomic groups. The data were obtained using this instrument at the 2.15 m telescope of CASLEO. We present 128 observations for 82 asteroids of different taxonomic types. These results revealed phase-polarization curves and polarimetric parameters for 20 asteroids, amounting to a total of 135 objects with sufficient good data in the Catalogue of Asteroid Polarization Curves. Using the values obtained for the objects with a taxonomic classification, we obtained the mean polarimetric parameters for 19 taxonomic types and the Barbarians. The asteroids with large mean scatter separation distances have a minimum of the phase-polarization curve greater than -1%, slopes at the inversion angle of less than 0.12-0.15% per degree, and perihelion distances 1.8<q<2.5 au; these measurements indicate the asteroids could have high or moderate albedos and that they are objects with perihelia in the inner asteroid belt. These large mean scatter separation distance values could be the result of an electrostatic mechanism acting on the small grains of the regolith, a manifestation of a coherent backscattering mechanism, or the result of a surface formed by a mixture of dark and bright particles.
- ID:
- ivo://CDS.VizieR/J/AJ/161/237
- Title:
- Positions of Triton with Sheshan Station telescope
- Short Name:
- J/AJ/161/237
- Date:
- 20 Jan 2022
- Publisher:
- CDS
- Description:
- The large time span and precise observational data of natural satellites is of great significance for updating their ephemerides and studying their dynamic characteristics. With the help of the new image-processing methods and the Gaia DR2 catalog, all CCD images of Triton taken with the 1.56m telescope of Shanghai Astronomical Observatory during 2005-2009 were reanalyzed. The median filtering algorithm is used for image preprocessing to remove the influence of the halo of Neptune, and an upgraded modified moment, called the intensity-square-weighted centroiding method, is applied to determine the centroids of the stars and Triton. A total of 2299 positions of Triton were obtained, including 263 new observed positions and 2036 updated observed positions. Such five-year time span data with high precision will be very helpful to improve the orbit parameters of Triton.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/1117
- Title:
- Possible Ceres asteroid paleo-family
- Short Name:
- J/MNRAS/458/1117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ceres is the largest and most massive body in the asteroid main belt. Observational data from the Dawn spacecraft reveal the presence of at least two impact craters about 280km in diameter on the Ceres surface, that could have expelled a significant number of fragments. Yet, standard techniques for identifying dynamical asteroid families have not detected any Ceres family. In this work, we argue that linear secular resonances with Ceres deplete the population of objects near Ceres. Also, because of the high escape velocity from Ceres, family members are expected to be very dispersed, with a considerable fraction of km-sized fragments that should be able to reach the pristine region of the main belt, the area between the 5J:-2A and 7J:-3A mean-motion resonances, where the observed number of asteroids is low. Rather than looking for possible Ceres family members near Ceres, here we propose to search in the pristine region.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A37
- Title:
- Prediction of stellar occultations 2012.5-2014
- Short Name:
- J/A+A/561/A37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The prediction tables of stellar occultations by 5 Centaurs and 34 TNOs (referred simply as TNOs hereafter) for the period 2012.5-2014 were built to support the investigation of the physical properties of (8405) Asbolus, (24835) 1995 SM55, (10199) Chariklo, (26375) 1999 DE9, (47171) 1999 TC36, (38628) Huya, (54598) Bienor, (55565) 2002 AW197, (55576) Amycus, (83982) Crantor, (119951) 2002 KX14, (307261) 2002 MS4, (84522) 2002 TC302, (55637) 2002 UX25, (55638) 2002 VE95, (119979) 2002 WC19, (120132) 2003 FY128, (174567) 2003 MW12, (120178) 2003 OP32, 2003 UZ413, (84922) 2003 VS2, (90568) 2004 GV9, 2004 NT33, (175113) 2004 PF115, (120347) Salacia, (120348) 2004 TY364, (144897) 2004 UX10, 2005 CC79 (2011 FX62), (303775) 2005 QU182, (145451) 2005 RM43, (145452) 2005 RN43, (145453) 2005 RR43, (202421) 2005 UQ513, 2007 JH43, (278361) 2007 JJ43, (225088) 2007 OR10, (229762) 2007 UK126, 2008 OG19, and 2010 EK139 for this period. These objects are important to understand the structure, origin, and evolution of the outer solar system. Our goal was to derive precise predictions. With this aim, we constructed astrometric star catalogues in the UCAC4 system covering their sky paths. For that, we carried out during 2011-2013 an observational program at the ESO2p2/WFI instrument covering the sky path of these 39 TNOs for the period 2012.5-2014. We made the astrometry of 550 GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50mas precision. The catalogue star positions were obtained in the UCAC4 frame with uncertainties of 40mas for stars up to magnitude completeness (about R=19). New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalogue positions as first epoch. The catalogues for all TNOs contain in all more than 12.4 million entries, covering the sky paths of the objects with 30 arcmin width. The magnitude completeness is about R=19 with a limit about R=21. Ephemeris offsets with about 10mas to 100mas precision were applied for each TNO orbit to improve the predictions. They were obtained during 2011-2013 from a parallel observational campaign carried out with telescope diameters from 0.6m to 2.2m. The 7343 candidate stars listed in the prediction tables were searched using a proximity radius of 650mas with the geocentric apparent orbit (corrected by ephemeris offsets) of the body considered. This radius is a little more than seven times the apparent radius of a body with Pluto's size (50mas) plus the apparent Earth radius (285 mas) as projected in the sky plane at 31AU (about the Pluto-Earth distance for 2008-2015). No threshold in R magnitude was used in the search for candidates, as relatively faint R objects may turn out to be bright infrared stars, perfect targets for the SOFIA observatory and for ground-based instruments well equipped with J, H, or K band detectors (J, H, and K magnitudes are promptly available in the tables if the star belongs to the 2MASS). Besides, events may be also favoured by slow shadow speeds of less than 20km/s. Also, no constraint on a geographic place was applied, as in principle SOFIA observations can be done from any sub-solar point on Earth. Events in daylight at sub-planet point were not excluded either, as they could yet be observable in the dark, right above the horizon, from places near the Earth terminator. We furnish here prediction tables for future and also for past stellar occultations covering the sky paths between 2012.5-2014. The importance of predictions for occultations still to come is obvious. But the predictions of past occultations are also useful for at least three reasons. First, they can be used by anyone as reference for ongoing fittings of light curves of recent past observed events. Second, they serve to derive ephemeris drifts by comparing expected and observed central instants and C/A values. Finally, they can be used as an external check for the accuracy and precision of our prediction tables. In all, for R=19 stars (catalogue magnitude completeness) and 40mas errors in the WFI positions, we may assume a bulk error of about 80mas for C/A, dominated by the ephemeris offsets errors of about 70mas. For about 40AU, this implies a shadow path uncertainty over the Earth of the order of 2300km. If the ephemeris offsets can be well determined to within 30mas precision, then a bulk error of 50mas in C/A can be achieved, leading to a precision of about 1400km for the WFI occultation path predictions. Thus, the probability of actually observing the occultation is not as high as hoped, but not despairingly small, especially if the event occurs above a dense, populated region in terms of astronomers, including amateurs, with access to telescopes.
- ID:
- ivo://CDS.VizieR/J/A+A/541/A142
- Title:
- Prediction of stellar occultations 2008-2015
- Short Name:
- J/A+A/541/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The prediction tables of stellar occultations by Eris, Haumea, Makemake, Quaoar, Orcus, Sedna, Varuna, Ixion, 2002TX300 and 2003AZ84 for 2008-2015 were built to support the investigation of the physical properties of large transneptunian objects - keystones in the study of structure, origin and evolution of the Solar System. Our goal was to derive precise, astrometric predictions. With this aim, we constructed astrometric star catalogs in the UCAC2 system covering their sky paths. For that, we have carried out in 2007-2009 an observational program at the ESO2p2/WFI instrument covering the sky path of these 10 large TNOs for the 2008-2015. We made the astrometry of 316 GB of images with the Platform for Reduction of Astronomical Images Automatically (PRAIA). By relatively simple astrometric techniques, we treated the overlapping observations and derived a field distortion pattern for the WFI mosaic of CCDs to within 50 mas precision. The catalog star positions were obtained in the UCAC2 frame with errors of 40mas for stars up to magnitude completeness (about R=19). New stellar proper motions were also determined with 2MASS and the USNO B1.0 catalog positions as first epoch. The catalogs of all TNOs contain in all more than 5.35 million stars with proper motions, covering the sky paths of the objects with 30 arcmin width. The magnitude completeness is about R=19 with a limit about R=21. Ephemeris offsets with about 50mas to 100mas precision were applied for each TNO orbit to improve the predictions. They were obtained during 2007-2010 from a parallel observational campaign carried out with 0.6m to 2.2m size telescopes. The 2718 candidate stars listed in the prediction tables were searched using a proximity radius of 335mas with the geocentric apparent orbit (corrected by ephemeris offsets) of the body considered. This radius is about the apparent radius of a body with Pluto's size (50mas) plus the apparent Earth radius (285mas) as projected in the sky plane at 31AU (about the Pluto-Earth distance for 2008-2015). No threshold in R magnitude was used in the search for candidates, as relatively faint R objects may turn out to be bright infrared stars, perfect targets for the SOFIA observatory and for ground-based instruments well equipped with H, J or K band detectors (H, J and K magnitudes are promptly available in the tables if the star belongs to the 2MASS). Besides, events may be also favored by slow shadow speeds of less than 20km/s. Also, no constraint on a geographic place was applied, as in principle SOFIA observations can be done from any sub-solar point on Earth. Events in daylight at sub-planet point were not excluded either, as they could yet be observable in the dark, right above the horizon, from places near the Earth terminator. We furnish here prediction tables for future and also for past stellar occultations covering the sky paths between 2008-2015. The importance of predictions for occultations still to come is obvious. But the predictions of past occultations are also useful for at least three reasons. First, they can be used by anyone as reference for ongoing fittings of light curves of recent past observed events. Second, they serve to derive ephemeris drifts by comparing expected and observed central instants and C/A values. Finally, they can be used as an external check for the accuracy and precision of our prediction tables. In all, for R=19 stars (catalog magnitude completeness) and 40mas errors in the WFI positions, we may assume a bulk error of about 80mas for C/A, dominated by the ephemeris offsets errors of about 70mas. For about 40AU, this implies a shadow path uncertainty over the Earth of the order of 2300km. If the ephemeris offsets can be well determined to within 30mas precision, then a bulk error of 50mas in C/A can be achieved, leading to a precision of about 1400km for the WFI occultation path predictions. Thus, the probability of actually observing the occultation is not as high as hoped, but not despairingly small, especially if the event occurs above a dense, populated region in terms of astronomers, including amateurs.
