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251. Hipparcos-Gaia (EDR3) Catalog of Accelerations
ID:
ivo://CDS.VizieR/J/ApJS/254/42
Title:
Hipparcos-Gaia (EDR3) Catalog of Accelerations
Short Name:
J/ApJS/254/42
Date:
28 Oct 2021 07:00:25
Publisher:
CDS
Description:
We present a cross-calibration of Hipparcos and Gaia EDR3 intended to identify astrometrically accelerating stars and to fit orbits to stars with faint, massive companions. The resulting catalog, the EDR3 edition of the Hipparcos-Gaia Catalog of Accelerations (HGCA), provides three proper motions with calibrated uncertainties on the EDR3 reference frame: the Hipparcos proper motion, the Gaia EDR3 proper motion, and the long-term proper motion given by the difference in position between Hipparcos and Gaia EDR3. Our approach is similar to that for the Gaia DR2 edition of the HGCA but offers a factor of ~3 improvement in precision thanks to the longer time baseline and improved data processing of Gaia EDR3. We again find that a 60/40 mixture of the two Hipparcos reductions outperforms either reduction individually, and we find strong evidence for locally variable frame rotations between all pairs of proper motion measurements. The substantial global frame rotation seen in DR2 proper motions has been removed in EDR3. We also correct for color- and magnitude-dependent frame rotations at a level of up to ~50{mu}as/yr in Gaia EDR3. We calibrate the Gaia EDR3 uncertainties using a sample of radial velocity standard stars without binary companions; we find an error inflation factor (a ratio of total to formal uncertainty) of 1.37. This is substantially lower than the position-dependent factor of ~1.7 found for Gaia DR2 and reflects the improved data processing in EDR3. While the catalog should be used with caution, its proper motion residuals provide a powerful tool to measure the masses and orbits of faint, massive companions to nearby stars.
252. Hipparcos Input Catalogue, Version 2
ID:
ivo://CDS.VizieR/I/196
Title:
Hipparcos Input Catalogue, Version 2
Short Name:
I/196
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Hipparcos Input Catalogue was constructed as the observing program for ESA's Hipparcos astrometry mission. This has resulted in a catalogue of stellar data including up-to-date information on positions, proper motions, magnitudes, colors, and when available, spectral types, radial velocities, multiplicity and variability information. The catalogue is complete to well-defined magnitude limits, and includes a substantial sampling of the most important stellar categories present in the solar neighbourhood beyond these limits. The magnitude limits vary from 7.3 to 9 magnitudes as a function of galactic latitude and spectral type, and there are no stars fainter than about V = 13 mag. 118000 stars are included in the Hipparcos Input Catalogue, about half of them have been selected within well-defined limits in V magnitude, spectral type and galactic latitude (the "survey"), half of them within proposed observing programs. The mean accuracies achieved, as demonstrated by comparison with the Hipparcos results (Turon et al. 1995A&A...304...82T) are 0.3 arcsec for the positions and 0.25 mag for the Hp magnitude, with accuracies of 0.02 mag or better for more than a third of the catalogue. The data set consists of the main catalogue, and the first supplement which contains more detailed information for multiple system components. Other supplements with identification charts can be found in the published version. A complete description is provided, either as a LaTeX file (intro.tex), or as a plain ascii file (intro.cat).
253. Hipparcos intermediate astrometric data
ID:
ivo://CDS.VizieR/J/A+AS/130/157
Title:
Hipparcos intermediate astrometric data
Short Name:
J/A+AS/130/157
Date:
21 Oct 2021
Publisher:
CDS
Description:
Summary of the great circle statistics for FAST and NDAC reduction results, allowing the distinction of great circles according to the number of accepted single star transits.
254. Hipparcos, the New Reduction
ID:
ivo://CDS.VizieR/I/311
Title:
Hipparcos, the New Reduction
Short Name:
I/311
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming accuracies for nearly all stars brighter than magnitude Hp=8 to be better, by up to a factor 4, than in the original catalogue. The new Hipparcos astrometric catalogue is checked for the quality of the data and the consistency of the formal errors as well as the possible presence of error correlations. The differences with the earlier publication are explained. Methods. The internal errors are followed through the reduction process, and the external errors are investigated on the basis of a comparison with radio observations of a small selection of stars, and the distribution of negative parallaxes. Error correlation levels are investigated and the reduction by more than a factor 10 as obtained in the new catalogue is explained. Results. The formal errors on the parallaxes for the new catalogue are confirmed. The presence of a small amount of additional noise, though unlikely, cannot be ruled out. Conclusions. The new reduction of the Hipparcos astrometric data provides an improvement by a factor 2.2 in the total weight compared to the catalogue published in 1997, and provides much improved data for a wide range of studies on stellar luminosities and local galactic kinematics.
255. HIP stars DEC proper motions comparison
ID:
ivo://CDS.VizieR/J/A+A/631/A145
Title:
HIP stars DEC proper motions comparison
Short Name:
J/A+A/631/A145
Date:
21 Oct 2021
Publisher:
CDS
Description:
The second solution of the Gaia catalog, which has been available since April 2018, plays an important role in the realization of the future Gaia reference frame. Since 1997, the reference frame has been materialized by the optical HIPPARCOS positions of about 120000 stars. The HIPPARCOS has been compared with and linked to the International Celestial Reference Frame (ICRF). The ICRF is materialized by means of the radio positions of extragalactic sources using very large baseline interferometry observations. Both, the HIPPARCOS and Gaia missions belong to the European Space Agency, and it is important to note that the Gaia catalog is going to replace the HIPPARCOS catalog. It has been shown that the International Latitude Service zenith telescope data pertaining to ground-based surveys that span a time baseline of about 80yr, and which are also key when measuring proper motions, could be useful for the accurate determination of {mu}_{delta}_ for 387 ILS stars. Therefore, in this study we aim first to reduce these stars to the HIPPARCOS reference system; second, to made our original catalog of {mu}_{delta}_, which we refer to as the ILS catalog, for these 387 bright stars; third, to present comparison results of the four catalogs by pairs (the ILS, HIPPARCOS or HIP, new HIPPARCOS or NHIP, and Gaia DR2); and fourth, to analyze the differences in {mu}_{delta}_ between pairs of catalogs to characterize the {mu}_{delta}_ errors for these catalogs with a special focus on the Gaia DR2 and ILS catalogs. At seven ILS sites around the world at latitude 39.1{deg}, a set of seven telescopes was used to monitor the latitude variation via observations of the same stars for about 80 yr. Here, the inverse task was applied to improve {mu}_{delta}_ values of the 387 HIPPARCOS stars using the previously mentioned observations. Due to the specific Horrebow-Talcott method of the measured star pair, it is difficult to determine {mu}_{delta}_ for each single star. However, we achieved this by developing the original method and in combination with the HIPPARCOS data. We used the previously developed least squares method and formula to determine the coefficients, which describe the systematic part of differences in {mu}_{delta}_ between the pairs of catalogs. We calculated the coefficients with the aforementioned formula (in line with the coordinates, stellar magnitude, and color index of every star) to compare ILS, HIP, NHIP, and Gaia DR2 data of {mu}_{delta}_ against each other by using the set of 387 stars. The presented differences of {mu}_{delta}_ show that the systematic errors in the four catalogs are nearly at the same level of 0.1mas/yr. This means that the DR2 and ILS {mu}_{delta}_ values are in good agreement with each other, and with values from the HIPPARCOS and new HIPPARCOS catalogs. Also, the random errors of differences are small ones; they are near 1mas/yr for ILS-HIP and ILS-NHIP, and about 2mas/yr for ILS-DR2, HIP-DR2, and NHIP-DR2. It is important to note that there is a similar level of proper motion formal errors in HIPPARCOS and new HIPPARCOS catalogs.
256. Historical and HST Astrometry of Sirius A,B
ID:
ivo://CDS.VizieR/J/ApJ/840/70
Title:
Historical and HST Astrometry of Sirius A,B
Short Name:
J/ApJ/840/70
Date:
21 Oct 2021
Publisher:
CDS
Description:
Sirius, the seventh-nearest stellar system, is a visual binary containing the metallic-line A1 V star Sirius A, the brightest star in the sky, orbited in a 50.13 year period by Sirius B, the brightest and nearest white dwarf (WD). Using images obtained over nearly two decades with the Hubble Space Telescope (HST), along with photographic observations covering almost 20 years and nearly 2300 historical measurements dating back to the 19th century, we determine precise orbital elements for the visual binary. Combined with the parallax and the motion of the A component, these elements yield dynamical masses of 2.063+/-0.023M_{sun}_ and 1.018+/-0.011M_{sun}_ for Sirius A and B, respectively. Our precise HST astrometry rules out third bodies orbiting either star in the system, down to masses of ~15-25M_{Jup}_. The location of Sirius B in the Hertzsprung-Russell diagram is in excellent agreement with theoretical cooling tracks for WDs of its dynamical mass, and implies a cooling age of ~126Myr. The position of Sirius B on the mass-radius plane is also consistent with WD theory, assuming a carbon-oxygen core. Including the pre-WD evolutionary timescale of the assumed progenitor, the total age of Sirius B is about 228+/-10Myr. We calculated evolutionary tracks for stars with the dynamical mass of Sirius A, using two independent codes. We find it necessary to assume a slightly subsolar metallicity, of about 0.85Z_{sun}_, to fit its location on the luminosity-radius plane. The age of Sirius A based on these models is about 237-247Myr, with uncertainties of +/-15Myr, consistent with that of the WD companion. We discuss astrophysical puzzles presented by the Sirius system, including the probability that the two stars must have interacted in the past, even though there is no direct evidence for this and the orbital eccentricity remains high.
257. HITEP. II. Transiting exoplanets imaging
ID:
ivo://CDS.VizieR/J/A+A/610/A20
Title:
HITEP. II. Transiting exoplanets imaging
Short Name:
J/A+A/610/A20
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of the second part of a high resolution imaging survey of hot Jupiter host stars. We search for binary companions to known transiting exoplanet host stars, in order to determine the multiplicity properties of hot Jupiter host stars. We also search for and characterise unassociated stars along the line of sight, allowing photometric and spectroscopic observations of the planetary system to be corrected for contaminating light.
258. HKE Sydney Catalog
ID:
ivo://CDS.VizieR/I/73
Title:
HKE Sydney Catalog
Short Name:
I/73
Date:
21 Oct 2021
Publisher:
CDS
Description:
The methods for constructing a catalogue of 20457 star positions for the epoch 1964 between -48 and -58{deg} declination are described. The positions were obtained by the overlap method, and images generated by a coarse diffraction grating were employed to control magnitude-related effects on the position. A selection of about 2 faint Astrographic Catalog (AC) stars per square degree was included to serve as material for the eventual determination of magnitude effects on the AC positions. The standard error of a catalogued position estimate based on 2 images is 0.12'' in either coordinate.
259. HK survey emission-line candidates
ID:
ivo://CDS.VizieR/J/AJ/112/1188
Title:
HK survey emission-line candidates
Short Name:
J/AJ/112/1188
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a list of 218 additional candidate emission-line objects discovered with the northern and southern HK interference-filter/ objective-prism survey of Beers and collaborators. The objects have apparent magnitudes in the range 10<=B<=16, several magnitudes fainter than obtained with previous prism surveys of similar resolution. Of the new candidates, 73 have been previously identified. The total list of HK-survey emission-line candidates now numbers 376 objects, 104 of which were noted by previous surveys.
260. Hot Stuff for One Year (HSOY)
ID:
ivo://CDS.VizieR/I/339
Title:
Hot Stuff for One Year (HSOY)
Short Name:
I/339
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recently, the first installment of data from ESA's Gaia astrometric satellite mission (Gaia DR1) was released, containing positions of more than 1 billion stars with unprecedented precision, as well as proper motions and parallaxes, however only for a subset of 2 million objects. The second release will include those quantities for most objects. In order to provide a dataset that bridges the time gap between the Gaia DR1 and Gaia DR2 releases and partly remedies the lack of proper motions in the former, HSOY ("Hot Stuff for One Year") was created as a hybrid catalog between Gaia and ground-based astrometry, featuring proper motions (but no parallaxes) for a large fraction of the DR1 objects. While not attempting to compete with future Gaia releases in terms of data quality or number of objects, the aim of HSOY is to provide improved proper motions partly based on Gaia data, allowing studies to be carried out just now or as pilot studies for later projects requiring higher-precision data. The HSOY catalog was compiled using the positions taken from Gaia DR1 combined with the input data from the PPMXL catalog, employing the same weighted least-squares technique that was used to assemble the PPMXL catalog itself. This effect resulted in a four-parameter astrometric catalog containing 583 million stars, with Gaia DR1 quality positions and proper motions with precisions from far less than 1 mas/yr to 5 mas/yr, depending on object brightness and location on the sky.

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