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Data Re-processing of HIPPARCOS

Research project PX/6/SS/01 (Research action PX)


Persons :

  • Prof.  JORISSEN Alain - Université Libre de Bruxelles (ULB)
    Coordinator of the project
    Financed belgian partner
    Duration: 1/1/2001-31/12/2005

Description :

In this project, the Hipparcos Intermediate Astrometric Data (IAD) of specific kinds of stars (spectroscopic binaries, Mira and carbon stars, stars flagged as `Variable-Induced Movers') have been thoroughly investigated and re-processed. This project thus increases the scientific return of the Hipparcos mission, and prepare the future (Gaia) thanks to the lessons learned from Hipparcos. It is the continuation of the PRODEX project PX/5B/SS/16, which showed that a substantial number of new astrometric orbits may still be extracted from the IAD for stars with a known spectroscopic orbit.

The goals of the present project are:

1. to reprocess the Intermediate Astrometric Data (IAD) of spectroscopic binaries;
2. to reprocess the IAD of carbon and Mira stars:

2.1 Reprocess the IAD of the 500+ carbon and Mira stars observed by Hipparcos, using an improved algorithm.
2.2 Understand why carbon and Mira stars contain an abnormally large number of outlying measurements.
Is it due to:

- light variations (poor measurements at minimum light)?
- unrecognized binary motion?
- variable, spotty disks?

2.3 Derive the Period-Luminosity relationship of Mira stars from the improved astrometric parameters.
2.4 Locate the various carbon-star subtypes (CH, R, J, N, R CrB) in the Hertzsprung-Russell diagram, using their revised parallaxes, and discuss the astrophysical implications.

The achievements of the project are described in several scientific papers.

Satellite(s) or flight opportunity(ies):

HIPPARCOS


Field of research:

Space Sciences


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