Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

HD 202110


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

Re-processing the Hipparcos Transit Data and Intermediate Astrometric Data of spectroscopic binaries. I. Ba, CH and Tc-poor S stars
Only 235 entries were processed as astrometric binaries with orbits inthe Hipparcos and Tycho Catalogue (\cite{Hipparcos}). However, theIntermediate Astrometric Data (IAD) and Transit Data (TD) made availableby ESA make it possible to re-process the stars that turned out to bespectroscopic binaries after the completion of the Catalogue. This paperillustrates how TD and IAD may be used in conjunction with the orbitalparameters of spectroscopic binaries to derive astrometric parameters.The five astrometric and four orbital parameters (not already known fromthe spectroscopic orbit) are derived by minimizing an objective function(chi 2) with an algorithm of global optimization. This codehas been applied to 81 systems for which spectroscopic orbits becameavailable recently and that belong to various families ofchemically-peculiar red giants (namely, dwarf barium stars, strong andmild barium stars, CH stars, and Tc-poor S stars). Among these 81systems, 23 yield reliable astrometric orbits. These 23 systems make itpossible to evaluate on real data the so-called ``cosmic error''described by Wielen et al. (1997), namely the fact that an unrecognizedorbital motion introduces a systematic error on the proper motion.Comparison of the proper motion from the Hipparcos catalogue with thatre-derived in the present work indicates that the former are indeed faroff the present value for binaries with periods in the range 3 to ~ 8years. Hipparcos parallaxes of unrecognized spectroscopic binaries turnout to be reliable, except for systems with periods close to 1 year, asexpected. Finally, we show that, even when a complete orbital revolutionwas observed by Hipparcos, the inclination is unfortunately seldomprecise. Based on observations from the Hipparcos astrometric satelliteoperated by the European Space Agency (ESA 1997).

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:Ιππάριον
Right ascension:21h13m39.29s
Declination:+05°58'19.8"
Apparent magnitude:7.978
Distance:240.964 parsecs
Proper motion RA:12.7
Proper motion Dec:-8.7
B-T magnitude:9.728
V-T magnitude:8.123

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 202110
TYCHO-2 2000TYC 539-290-1
USNO-A2.0USNO-A2 0900-19458932
HIPHIP 104784

→ Request more catalogs and designations from VizieR