Nearby young stars

Astronomy & Astrophysics, Main Journal (accepted)

R. Wichmann [1], J.H.M.M. Schmitt [1], S. Hubrig [2]

  1. Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany
  2. European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München, Germany

Abstract

We present the results of an extensive all-sky survey of nearby stars of spectral type F8 or later in a systematic search of young (zero-age main sequence) objects. Our sample has been derived by cross-correlating the ROSAT All-Sky Survey and the TYCHO catalog, yielding a total of 754 candidates distributed more or less randomly over the sky. Follow-up spectroscopy of these candidate objects has been performed on 748 of them. We have discovered a tight kinematic group of ten stars with extremely high lithium equivalent widths that are presumably younger than the Pleiades, but again distributed rather uniformly over the sky. Furthermore, about 43 per cent of our candidates have detectable levels of lithium, thus indicating that these are relatively young objects with ages not significantly above the Pleiades age.

Key words: Surveys - solar neighbourhood - Stars: kinematics - Stars: late-type

Contact: Rainer Wichmann.

Preprint: (gzipped PS, 192 KB), (PDF, 506 KB)