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Start Over Subject astrometry Capability Type Table Access Protocol
421. Precession-nutation procedures (IAU 2006)
ID:
ivo://CDS.VizieR/J/A+A/459/981
Title:
Precession-nutation procedures (IAU 2006)
Short Name:
J/A+A/459/981
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 2006 IAU General Assembly has adopted the P03 model of Capitaine et al. (2003A&A...412..567C) recommended by the WG on precession and the ecliptic (Hilton et al., 2006, Celest. Mech. Dyn. Astron. 94, 351) to replace the IAU 2000 model, which comprised the Lieske et al. (1977A&A....58....1L) model with adjusted rates. Practical implementations of this new "IAU 2006" model are therefore required, involving choices of procedures and algorithms. The purpose of this paper is to recommend IAU 2006 based precession-nutation computing procedures, suitable for different classes of application and achieving high standards of consistency.
422. Precise astrometry with VLBA (VIPS)
ID:
ivo://CDS.VizieR/J/AJ/142/89
Title:
Precise astrometry with VLBA (VIPS)
Short Name:
J/AJ/142/89
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present accurate positions for 857 sources derived from the astrometric analysis of 16 eleven-hour experiments from the Very Long Baseline Array imaging and polarimetry survey at 5GHz (VIPS). Among the observed sources, positions of 430 objects were not previously determined at milliarcsecond-level accuracy. For 95% of the sources the uncertainty of their positions ranges from 0.3 to 0.9mas, with a median value of 0.5mas. This estimate of accuracy is substantiated by the comparison of positions of 386 sources that were previously observed in astrometric programs simultaneously at 2.3/8.6GHz. Surprisingly, the ionosphere contribution to group delay was adequately modeled with the use of the total electron content maps derived from GPS observations and only marginally affected estimates of source coordinates.
423. Precise CCD positions of Phoebe in 2011-2014
ID:
ivo://CDS.VizieR/J/MNRAS/449/2638
Title:
Precise CCD positions of Phoebe in 2011-2014
Short Name:
J/MNRAS/449/2638
Date:
21 Oct 2021
Publisher:
CDS
Description:
346 new CCD observations during the years 2011-2014 have been reduced to derive the precise positions of Phoebe, the ninth satellite of Saturn. The observations were made by the 2.4 m telescope at Yunnan Observatory over nine nights. Due to the use of a focal-reducer on the telescope, its significant geometric distortion is solved for and removed for each CCD field of view. The positions of Phoebe are measured with respect to the stars in UCAC2 catalogue (Cat. I/289). The theoretical position of Phoebe was retrieved from the Institute de Mechanique Celeste et de Calcul des Ephemerides (IMCCE) ephemeris which includes the latest theory PH12 by Desmars et al. (2013, J/A+A/553/A36), while the position of Saturn was obtained from the Jet Propulsion Laboratory ephemeris DE431. Our results show that the mean O-Cs (observed minus computed) are -0.02 and -0.07 arcsec in right ascension and declination, respectively. The dispersions of our observations are estimated at about 0.04 arcsec in each direction.
424. Precise positions of RR Lyrae Stars with Vmax>12.5
ID:
ivo://CDS.VizieR/J/A+A/442/381
Title:
Precise positions of RR Lyrae Stars with Vmax>12.5
Short Name:
J/A+A/442/381
Date:
21 Oct 2021
Publisher:
CDS
Description:
RR Lyrae stars are of great importance for investigations of Galactic structure. However, a complete compendium of all RR-Lyraes in the solar neighbourhood with accurate classifications and coordinates does not exist to this day. Here we present a catalogue of 561 local RR-Lyrae stars (V_max_>=12.5mag) according to the magnitudes given in the Combined General Catalogue of Variable Stars (GCVS) and 16 fainter ones. The Tycho2 catalogue contains ~100 RR Lyr stars. However, many objects have inaccurate coordinates in the GCVS, the primary source of variable star information, so that a reliable cross-identification is difficult. We identified RR Lyrae from both catalogues based on an intensive literature search. In dubious cases we carried out photometry of fields to identify the variable. Mennessier & Colome (2002, Cat. <J/A+A/390/173>) have published a paper with Tyc2-GCVS identifications, but we found that many of their identifications are wrong.
425. Precise Radio Source Positions from Mark III VLBI
ID:
ivo://CDS.VizieR/I/151
Title:
Precise Radio Source Positions from Mark III VLBI
Short Name:
I/151
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains observations from 600 Mark III VLBI experiments from conducted between 1979 to 1988. These experiments resulted in 237681 acceptable pairs of group delay and phase delay rate observations. These have been used to derive positions of 182 extra-galactic radio sources with typical formal standard errors less than 1 mas. The right ascension zero point of this reference frame has been aligned with the FK5 by using the optical positions of 28 extragalactic radio sources whose positions are on the FK5 system. Also included are the Mark III VLBI stations and a summary of the analysis configuration.
426. Precision meteor orbits
ID:
ivo://CDS.VizieR/J/A+AS/128/179
Title:
Precision meteor orbits
Short Name:
J/A+AS/128/179
Date:
21 Oct 2021
Publisher:
CDS
Description:
Orbital elements, encounter data and other relevant information of 359 photographic meteors (Table 2 of the paper).
427. Predicted Microlensing Events by nearby VLM objects
ID:
ivo://CDS.VizieR/J/AcA/68/351
Title:
Predicted Microlensing Events by nearby VLM objects
Short Name:
J/AcA/68/351
Date:
21 Oct 2021
Publisher:
CDS
Description:
Microlensing events can be used to directly measure the masses of single field stars to a precision of ~1-10%. The majority of direct mass measurements for stellar and sub-stellar objects typically only come from observations of binary systems. Hence microlensing provides an important channel for direct mass measurements of single stars. The Gaia satellite has observed ~1.7 billion objects, and analysis of the second data release has recently yielded numerous event predictions for the next few decades. However, the Gaia catalog is incomplete for nearby very-low-mass objects such as brown dwarfs for which mass measurements are most crucial. We employ a catalog of very-low-mass objects from Pan-STARRS data release 1 (PDR1) as potential lens stars, and we use the objects from Gaia data release 2 (GDR2) as potential source stars. We then search for future microlensing events up to the year 2070. The Pan-STARRS1 objects are first cross-matched with GDR2 to remove any that are present in both catalogs. This leaves a sample of 1718 possible lenses. We fit MIST isochrones to the Pan-STARRS1, AllWISE and 2MASS photometry to estimate their masses. We then compute their paths on the sky, along with the paths of the GDR2 source objects, until the year 2070, and search for potential microlensing events. Source-lens pairs that will produce a microlensing signal with an astrometric amplitude of greater than 0.131mas, or a photometric amplitude of greater than 0.4mmag, are retained.
428. Predicted Microlensing Events for the 21st Century
ID:
ivo://CDS.VizieR/J/AcA/68/183
Title:
Predicted Microlensing Events for the 21st Century
Short Name:
J/AcA/68/183
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using Gaia data release 2 (GDR2, Cat. I/345), we present an almanac of 2509 predicted microlensing events, caused by 2130 unique lens stars, that will peak between July 25, 2026 and the end of the century. This work extends and completes a thorough search for future microlensing events initiated by Bramich and Nielsen using GDR2. The almanac includes 161 lenses that will cause at least two microlensing events each. All of the predicted microlensing events in the almanac will exhibit astrometric signals that are detectable by observing facilities with an angular resolution and astrometric precision similar to, or better than, that of the Hubble Space Telescope (e.g., NIRCam on the James Webb Space Telescope), although the events with the most extreme source-to-lens contrast ratios may be challenging. Ground-based telescopes of at least 1 m in diameter can be used to observe many of the events that are also expected to exhibit a photometric signal.
429. Predicted microlensing events from Gaia DR2
ID:
ivo://CDS.VizieR/J/A+A/618/A44
Title:
Predicted microlensing events from Gaia DR2
Short Name:
J/A+A/618/A44
Date:
21 Oct 2021
Publisher:
CDS
Description:
I search for source-lens pairs in Gaia Data Release 2 (GDR2, Cat. I/345) that could potentially lead to microlensing events between 25th July 2014 and 25th July 2026. I estimate the lens masses using GDR2 photometry and parallaxes, and appropriate model stellar isochrones. Combined with the source and lens parallax measurements from GDR2, this allows the Einstein ring radius to be computed for each source-lens pair. By considering the source and lens paths on the sky, I calculate the microlensing signals that are to be expected.
430. Predicted positions of {beta}Pictoris b and c
ID:
ivo://CDS.VizieR/J/AJ/161/179
Title:
Predicted positions of {beta}Pictoris b and c
Short Name:
J/AJ/161/179
Date:
18 Jan 2022
Publisher:
CDS
Description:
We present a comprehensive orbital analysis to the exoplanets {beta}Pictoris b and c that resolves previously reported tensions between the dynamical and evolutionary mass constraints on {beta}Picb. We use the Markov Chain Monte Carlo orbit code orvara to fit 15years of radial velocities and relative astrometry (including recent GRAVITY measurements), absolute astrometry from Hipparcos and Gaia, and a single relative radial velocity measurement between {beta}Pic A and b. We measure model-independent masses of 9.3_-2.5_^+2.6^M_Jup_ for {beta}Picb and 8.3{+/-}1.0M_Jup_ for {beta}Picc. These masses are robust to modest changes to the input data selection. We find a well-constrained eccentricity of 0.119{+/-}0.008 for {beta}Picb, and an eccentricity of 0.21_-0.09_^+0.16^ for {beta}Picc, with the two orbital planes aligned to within ~0.5{deg}. Both planets' masses are within ~1{sigma} of the predictions of hot-start evolutionary models and exclude cold starts. We validate our approach on N-body synthetic data integrated using REBOUND. We show that orvara can account for three-body effects in the {beta}Pic system down to a level ~5 times smaller than the GRAVITY uncertainties. Systematics in the masses and orbital parameters from orvara's approximate treatment of multiplanet orbits are a factor of ~5 smaller than the uncertainties we derive here. Future GRAVITY observations will improve the constraints on {beta}Picc's mass and (especially) eccentricity, but improved constraints on the mass of {beta}Picb will likely require years of additional radial velocity monitoring and improved precision from future Gaia data releases.

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