Search for new T Tauri stars in the Cepheus-Cassiopeia region

¹ Astrophysikalisches Institut und Universitäts-Sternwarte Jena, Schillergäßchen 2-3, 07745, Jena, Germany e-mail: tatihara@astro.uni-jena.de
² Konkoly Observatory of Hungarian Academy of Sciences, Budapest, Hungary
³ Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan

Received: 18 October 2004
Accepted: 18 February 2005

Abstract

The Cepheus-Cassiopeia star-forming region has been searched for new T Tauri stars (TTSs) based on the ROSAT all sky survey (RASS). Optical spectroscopic observations were carried out toward 45 GSC stellar counterparts of RASS sources looking for the Li absorption line (6708 Å), a sign of youth. The detection of this line resulted in finding 11 to 16 new TTSs in this region. Using follow-up optical photometric observations and evolutionary models these Li-rich stars are revealed to be young low-mass stars. The most of the young stars are separated from the molecular clouds by ~10 pc, significantly more than in Chamaeleon. A group of the new TTSs are isolated from the CO clouds and distributed inside the previously determined CO void. Possible formation scenarios including the interaction with the supernova shock for the isolated TTSs are discussed.