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Start Over Subject astrometry Validation Level 2
181. Double stars measurements at Nice Obs. III.
ID:
ivo://CDS.VizieR/J/A+AS/147/251
Title:
Double stars measurements at Nice Obs. III.
Short Name:
J/A+AS/147/251
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present recent measurements of visual double stars made at the Nice Observatory (3rd series). We also report the discovery of a new double star: JCT 4. Moreover we give a more precise position of the double star DOO 35.
182. Double star speckle measures
ID:
ivo://CDS.VizieR/J/AJ/131/1000
Title:
Double star speckle measures
Short Name:
J/AJ/131/1000
Date:
21 Oct 2021
Publisher:
CDS
Description:
Position angle and separation measures of 482 primarily southern binary stars are presented. These were obtained from speckle observations taken at the Carlos U. Cesco Observatory, El Leoncito, Argentina, using a multianode microchannel array detector during the period 1994 July to 1996 July.
183. Dumb-bell galaxies in Southern Rich Clusters
ID:
ivo://CDS.VizieR/J/A+AS/95/1
Title:
Dumb-bell galaxies in Southern Rich Clusters
Short Name:
J/A+AS/95/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
184. Earth Orientation Catalog 4 (EOC-4)
ID:
ivo://CDS.VizieR/J/A+A/509/A3
Title:
Earth Orientation Catalog 4 (EOC-4)
Short Name:
J/A+A/509/A3
Date:
21 Oct 2021
Publisher:
CDS
Description:
The astrometric ground-based observations of latitude / universal time variations, covering the interval 1899.7-2003.0, were used in combination with Hipparcos / Tycho positions and some older ground-based catalogs to construct a family of catalogs, tailored for long-term Earth rotation studies. These catalogs, called Earth Orientation Catalogs (EOC-1 through EOC-3) yielded more accurate proper motions than the original Hipparcos Catalogue, and its latest version, EOC-3, even periodic motions for a large portion of the stars. About 4.5 million observations made at 33 observatories are combined with the catalogs ARIHIP, TYCHO-2 etc... in order to obtain EOC-4. Spectral analysis of ground-based data and comparison with the USNO Sixth Catalog of Orbits of Visual Binary Stars are used to discover which of the observed objects display periodic motions, and improved combination procedures are used. The catalog contains 4418 different objects (i.e., stars, components of double stars, photocenters), out of which 599 have significant orbital motions.
185. EMCCD observations of the 2018 Draconids
ID:
ivo://CDS.VizieR/J/A+A/635/A153
Title:
EMCCD observations of the 2018 Draconids
Short Name:
J/A+A/635/A153
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several authors predicted an outburst of the Draconid meteor shower in 2018, but with an uncertain level of activity. Optical meteor observations were used to derive the population and mass indices, flux, and radiant positions of Draconid meteors. We performed 90 minutes of multi-station observations after the predicted peak of activity were performed using highly sensitive Electron Multiplying Charge Coupled Device (EMCCD) cameras. The data calibration is discussed in detail. A novel maximum likelihood estimation method of computing the population and mass index with robust error estimation was developed. We apply the method to observed Draconids and use the values to derive the flux. Meteor trajectories are computed and compared to predicted radiant positions from meteoroid ejection models. We find a mass index of 1.74+/-0.18 in the 30 min bin after the predicted peak, and 2.32+/-0.27 in the subsequent 60 min. The location and the dispersion of the radiant are a good match to modeled values, but there is an offset of 0.4{deg} in solar longitude.
186. Emission-line stars in Vela Molecular Ridge
ID:
ivo://CDS.VizieR/J/A+AS/104/233
Title:
Emission-line stars in Vela Molecular Ridge
Short Name:
J/A+AS/104/233
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
187. Errors in the FK5 Catalog
ID:
ivo://CDS.VizieR/J/AJ/114/850
Title:
Errors in the FK5 Catalog
Short Name:
J/AJ/114/850
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents new positions for 689 FK5 stars determined directly in the extragalactic reference system from CCD scan observations made with the Flagstaff Astrometric Scanning Transit Telescope (FASTT). All the observations were made in 1994-1996 with an accuracy of ~+/-40mas in each coordinate. When these positions are compared with their counterparts in the FK5 catalog, systematic errors in the FK5 are found that vary in both right ascension and declination and can be as large as 100 mas in magnitude. No magnitude-dependent errors in the FK5 were found. Moreover, the true error in FK5 star positions is determined to be ~+/-80mas in both coordinates or two times the expected catalog positional errors. There is an excellent agreement between the systematic errors in the FK5 found in this paper and those presented in Lindegren et al. (1995A&A...304...44L) comparing FK5 and Hipparcos 30-month star positions. By comparing corresponding FASTT and FK5 star positions, the link between the optical and extragalactic reference frames was determined and is given by the following rotations ({omega}_x_,{omega}_y_,{omega}_z_) = (3+/-5, 25+/-5, 16+/-4) (s.e.) mas, which agree well with previous determinations made by other investigators. Two of the rotations ({omega}_y_,{omega}_z_) are significantly larger than their standard errors and, therefore, presumably real. Finally, since these rotations are small (<=25mas), the FK5 and extragalactic reference frames must be closely aligned to one another.
188. Events of Saturn satellites during 2009 equinox
ID:
ivo://CDS.VizieR/J/A+A/485/293
Title:
Events of Saturn satellites during 2009 equinox
Short Name:
J/A+A/485/293
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Saturnian equinox will occur in 2009; i.e., the Sun (and the Earth, very close to the Sun as seen from Saturn) will be in the equatorial plane of Saturn. Eclipses of the satellites by Saturn or mutual eclipses and occultations will occur among the seven first satellites orbiting in the Saturnian equatorial plane. This paper provides predictions of these events, along with information useful for observing them. Such events are uncommon, since they only occur every 15 years during the Saturnian equinox. The present dynamical models of motion of the Saturnian satellites include many effects on their motion. One needs accurate observations, such as mutual events, to determine all the relevant parameters.
189. Extended Hipparcos Compilation (XHIP)
ID:
ivo://CDS.VizieR/V/137D
Title:
Extended Hipparcos Compilation (XHIP)
Short Name:
V/137D
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Extended Hipparcos Compilation (XHIP) cross-references the New Hipparcos Reduction (HIP2, Cat. I/311) with relatable data from a broad survey of presently available sources. The resulting collection uniquely assigns 116,096 spectral classifications, 46,392 radial velocities, and 19,097 iron abundances [Fe/H] to Hipparcos stars. Stellar classifications from SIMBAD and indications of multiplicity from either CCDM (Cat. I/274) or WDS (Cat. B/wds) are provided. Parameters for solar encounters and Galactic orbits are calculated for a subset of stars that can be made kinematically complete. Memberships in open clusters and stellar associations are assigned. We also provide stellar ages from The Geneva-Copenhagen survey of the Solar neighbourhood III (Cat. V/130), identifications of exoplanet host stars, and supplemental photometry from 2MASS (Cat. II/246) and SIMBAD.
190. Extended Meingast 1 source catalogue
ID:
ivo://CDS.VizieR/J/A+A/639/A64
Title:
Extended Meingast 1 source catalogue
Short Name:
J/A+A/639/A64
Date:
21 Oct 2021
Publisher:
CDS
Description:
Nearby stellar streams carry unique information on the dynamical evolution and disruption of stellar systems in the Galaxy, the mass distribution in the disk, and they provide unique targets for planet formation and evolution studies. Recently, Meingast 1, a 120{deg} stellar stream with a length of at least 400pc, was discovered. We aim to revisit the Meingast 1 stream to search for new members within its currently known 400pc extent, using Gaia DR2 data and an innovative machine learning approach. We used a bagging classifier of one-class support vector machines with Gaia DR2 data to perform a 5D search (positions and proper motions) for new stream members. The ensemble was created by randomly sampling 2.4 million hyper-parameter realizations admitting classifiers that fulfill a set of prior assumptions. We used the variable prediction frequency resulting from the multitude of classifiers to estimate a stream membership criterion, which we used to select high-fidelity sources. We used the HR diagram and the Cartesian velocity distribution as test and validation tools. We find about 2000 stream members with high fidelity, or about an order of magnitude more than previously known, unveiling the stream's population across the entire stellar mass spectrum, from B stars to M stars, including white dwarfs. We find that, apart from being slightly more metal poor, the HRD of the stream is indistinguishable from that of the Pleiades cluster. For the mass range at which we are mostly complete, ~0.2M_{sun}_<M<~4M_{sun}_, we find a normal IMF, allowing us to estimate the total mass of stream to be about 2000M_{sun}_, making this relatively young stream by far the most massive one known. In addition, we identify several white dwarfs as potential stream members. The nearby Meingast 1 stream, due to its richness, age, and distance, is a new fundamental laboratory for star and planet formation and evolution studies for the poorly studied and gravitationally unbound star formation mode. We also demonstrate that one-class support vector machines can be effectively used to unveil the full stellar populations of nearby stellar systems with Gaia data.

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