A 3-D Survey of the Solar Neighborhood with DIVA
Abstract
Our knowledge on stars in the Solar neighborhood is one of the main starting points for investigations of the stellar luminosity function, the initial mass function as well as for the search for planetary systems. Future missions for the detection of extrasolar planets (SIM, TPF, DARWIN) will (have to) concentrate on very nearby stars (d < 10 pc) in order to be able to reveal not only Jupiter-class but also Earth-like planets. The number of missing stars (mainly cool dwarfs are expected) within this distance limit was estimated as 130 systems compared to 234 known ones (Henry et al. 1997). DIVA (Double Interferometer for Visual Astrometry) is a small satellite planned for launch in 2003. It will measure positions, proper motions and parallaxes, magnitudes and colours of 30 to 40 million stars, i. e. observe several hundred times as many stars as Hipparcos, at typically four times the precision of Hipparcos. For > 250,000 stars, parallaxes will be provided with relative accuracy better than 10%. Due to high sensitivity of the DIVA detectors between 600 nm and 900 nm, and because of the automatic detection on board, red stars and brown dwarfs are preferred objects in the DIVA survey. A representative sample of late-M and L dwarf spectra has been used for the simulation of DIVA raw data (dispersed and undispersed interferometric fringes) in order to estimate the limiting magnitude and accuracy which can be reached for these objects. Whereas most known nearby stars were found by their large proper motions, DIVA will provide an unbiased survey via direct distance measurements. Statistical properties of the survey are described.
- Publication:
-
Astronomische Gesellschaft Meeting Abstracts
- Pub Date:
- 2000
- Bibcode:
- 2000AGM....16..P83S