AAS 201st Meeting, January, 2003
Session 21. Planetary Systems: Instrumentation and Surveys
Poster, Monday, January 6, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[21.11] A Catalogue of Low Mass Stars Found in STIS Parallels

E. Malumuth (SSAI/GSFC)

A careful examination of a well defined subset of the Space Telescope Imaging Spectrograph (STIS) parallel observations has been conducted. From these data we have amassed a catalog of close to 300 spectroscopically confirmed M type stars ranging in brightness from v~16 mag to v~23 mag, and nearly complete to v~22 mag. Each field examined was obtained between 14 August 1997 and 25 July 2000, had a galactic latitude <-20 degrees or >+20 degrees and had at least 2 images and 2 spectral images (so that cosmic ray hits could be removed). There were 626 fields which met those selection criteria covering 435 square degrees of the sky. However, a number of these fields had to be thrown out due to crowding of the stars (those fields were typically in the Magellanic clouds and globular clusters).

Each field was examined and a quick extraction of the spectrum of every star brighter than v~23 mag was made. In practice many stars between v~22 mag and v~23 mag were either missed or too faint to get a reasonable extraction, however the catalog should be nearly complete brighter than v~22 mag. Each extracted spectrum was automatically compared to a suite of template stars ranging form O type to L type. All stars whose best match was K8 or later were noted as candidate M or later type stars. These stars were then extracted taking care to avoid stars in the background, and those stars whose slitless spectra overlapped. These careful extractions were compared to the template spectra by eye to confirm the spectral type and luminosity class. Of about 340 candidate M stars 284 were confirmed in this way. A single M9V star was the latest type found.

The catalogue will be presented along with a preliminary analysis of the properties of the stars (i.e. luminosity function, numbers of M stars of each type found Vs expected number, given the magnitude limit and area searched).

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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.