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521. Speckle observations of binary systems
ID:
ivo://CDS.VizieR/J/A+A/367/865
Title:
Speckle observations of binary systems
Short Name:
J/A+A/367/865
Date:
21 Oct 2021
Publisher:
CDS
Description:
From speckle observations made with the PISCO speckle camera at the Pic du Midi Observatory, we present high angular resolution astrometric data for 43 binary stars already observed by the Hipparcos satellite. This sample consists of mainly new Hipparcos eclipsing binaries with a visual companion closer than one arcsecond, chosen with the aim to study the dynamical implications of a third component on the observational parameters of the eclipsing system. In addition, we also included a selection of close visual binaries with few speckle data in order to analyse possible systematic departures between the speckle and the non-speckle orbits. The reduction method and the results are presented in detail. For the close visual binaries we confront our observations with the ephemerides based on the best known orbits. For the wide visual binaries the confrontation is made directly with the Hipparcos data. Our observations are consistent both with previous speckle data and with most of the Hipparcos measurements.
522. Spectroscopic survey of 479 thick disc stars
ID:
ivo://CDS.VizieR/J/A+A/535/A107
Title:
Spectroscopic survey of 479 thick disc stars
Short Name:
J/A+A/535/A107
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the era of large spectroscopic surveys, Galactic archaeology aims to understand the formation and evolution of the Milky Way by means of large datasets. In particular, the kinematic and chemical study of the thick disc can give valuable information on the merging history of the Milky Way. Our aim is to detect and characterise the Galactic thick disc chemically and dynamically by analysing F, G and K stars, whose atmospheres reflect their initial chemical composition. We performed a spectroscopic survey of nearly 700 stars probing the Galactic thick disc far from the solar neighbourhood towards the Galactic coordinates (l~277{deg}, b~47{deg}). The derived effective temperatures, surface gravities and overall metallicities were then combined with stellar evolution isochrones, radial velocities and proper motions to derive the distances, kinematics and orbital parameters of the sample stars. The targets belonging to each Galactic component (thin disc, thick disc, halo) were selected either on their kinematics or according to their position above the Galactic plane, and the vertical gradients were also estimated.
523. SPF1 Catalogue
ID:
ivo://CDS.VizieR/I/82
Title:
SPF1 Catalogue
Short Name:
I/82
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
524. SPF3 Catalogue
ID:
ivo://CDS.VizieR/I/78
Title:
SPF3 Catalogue
Short Name:
I/78
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
525. Spitzer follow up of 95 brown dwarfs
ID:
ivo://CDS.VizieR/J/ApJ/899/123
Title:
Spitzer follow up of 95 brown dwarfs
Short Name:
J/ApJ/899/123
Date:
14 Mar 2022 07:05:10
Publisher:
CDS
Description:
We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multiepoch Wide-field Infrared Survey Explorer (WISE) images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]-[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1"/yr; our fastest-moving discovery is WISEAJ155349.96+693355.2 ({mu}~2.15/yr), a possible T-type subdwarf. We also report a newly discovered wide-separation (~400au) T8 comoving companion to the white dwarf LSPMJ0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSRJ0002+6357 at 5.5 projected separation (~8700au if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf.
526. SPM 4.0 Catalog
ID:
ivo://CDS.VizieR/I/320
Title:
SPM 4.0 Catalog
Short Name:
I/320
Date:
21 Oct 2021
Publisher:
CDS
Description:
The SPM4 Catalog contains absolute proper motions, celestial coordinates, and B,V photometry for 103,319,647 stars and galaxies between the south celestial pole and -20 degrees declination. The catalog is roughly complete to V=17.5. It is based on photographic and CCD observations taken with the Yale Southern Observatory's double-astrograph at Cesco Observatory in El Leoncito, Argentina. The first-epoch survey, taken from 1965 to 1979, was entirely photographic. The second-epoch survey is approximately 1/3 photographic (taken from 1988 to 1998) and 2/3 CCD-based (taken from 2004 through 2008). Full details about the creation of the SPM4.0 catalog can be found in the paper, and also in the document "spm4_doc.txt" file which describes the original files, accessible from http://www.astro.yale.edu/astrom/spm4cat/
527. SPM Catalog 2.0
ID:
ivo://CDS.VizieR/I/277
Title:
SPM Catalog 2.0
Short Name:
I/277
Date:
21 Oct 2021
Publisher:
CDS
Description:
The SPM Catalog 2.0 provides positions, absolute proper motions and photographic BV photometry for over 320,000 stars and galaxies. The Catalog covers an area of ~3700 square degrees in an irregularly bounded band between declinations of -43 and -22 degrees, with a slight extension near the South Galactic Pole, but excluding fields in the plane of the Milky Way. Stars cover the magnitude range 5<V<18.5. The standard errors for the best measured stars are as follows: 20 mas for positions in each coordinate; 2mas/yr for absolute proper motions and 0.05mag for B and V magnitudes. Standard error estimates of positions, absolute proper motions and magnitudes are given for each individual object. In addition to the Catalog, a list of CCD calibrating sequences is provided. Note that all fields (and objects) contained in the 1.0 version of the Catalog are also included in this version. The values of the astrometric parameters for these objects, however, may be different due to refinements in the reduction procedure, (i.e. the SGP fields were re-reduced for inclusion in the SPM catalog 2.0).
528. Stability of VLBI reference frame
ID:
ivo://CDS.VizieR/J/A+A/375/661
Title:
Stability of VLBI reference frame
Short Name:
J/A+A/375/661
Date:
21 Oct 2021
Publisher:
CDS
Description:
The file table 2 gives the results of various tests and noise measurements performed on time serie of extragalactic radio source coordinates. Systematic and random behaviours in time serie of individual determinations of cooordinates for 283 sources over 1987-1999 are investigated. The random variability of the source coordinates is characterized by the {chi}^2^ test (Bevington, 1969, p.187) and the "goodness of fit (gof)" (Bevington, 1969, p.188). The Allan variance method (Allan, 1966, Proc. IEEE, vol. 54, 221) is used to investigate spectral characteristics of the time series. The source structure index (Fey & Charlot, 1997ApJS..111...95F, 2000, Cat. <J/ApJS/128/17>) qualifies the level of position disturbance expected at the date of the map (1 for the less disturbed, 4 for the most disturbed). The estimation of "linear rates" in the coordinates is a qualifier of the systematic parts of the source instability. This table contains the 283 best observed sources and is divided in three parts, with the left hand side giving general information and counts, the middle part giving statistics in the source local frame, and the right hand side giving statistics in the equatorial frame.
529. Standard errors for PPM and Tycho stars
ID:
ivo://CDS.VizieR/J/other/RoAJ/10.51
Title:
Standard errors for PPM and Tycho stars
Short Name:
J/other/RoAJ/10.
Date:
21 Oct 2021
Publisher:
CDS
Description:
The connection between the optical reference frame and the radio one constitutes one of the main purposes of the astrometry. The paper is pointing out the contribution of the Bucharest Observatory in this direction. The statistic analysis of the standard errors for the astrometric PPM and TYCHO stars is presented.
530. Star catalogue of Hevelius (1690)
ID:
ivo://CDS.VizieR/J/A+A/516/A29
Title:
Star catalogue of Hevelius (1690)
Short Name:
J/A+A/516/A29
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalogue by Johannes Hevelius with the positions and magnitudes of 1564 entries was published by his wife Elisabeth Koopman in 1690. We provide a machine-readable version of the catalogue, and briefly discuss its accuracy on the basis of comparison with data from the modern Hipparcos Catalogue. We compare our results with an earlier analysis by Rybka (1984), finding good overall agreement. The magnitudes given by Hevelius correlate well with modern values. The accuracy of his position measurements is similar to that of Brahe, with error distributions with widths of about 2 arcmin for longitudes and latitudes, but with more errors larger than 5 arcmin than expected for a Gaussian distribution. The position accuracy decreases slowly with magnitude. The fraction of stars with position errors larger than a degree is 1.5 per cent, rather smaller than the fraction of 5 per cent in the star catalogue of Brahe.