EDP Sciences
Free access
Volume 387, Number 1, May III 2002
Page(s) 129 - 138
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20020356

A&A 387, 129-138 (2002)
DOI: 10.1051/0004-6361:20020356

Near-infrared observations of candidate extrinsic S stars

X.-H. Wang1, 2 and P.-S. Chen1, 2

1  Yunnan Observatory, National Observatories, CAS, Kunming 650011, PR China
2  Joint Laboratory for Optical Astronomy, CAS, Beijing 100012, PR China

(Received 16 May 2001 / Accepted 30 January 2002 )

Photometric observations in the near infrared for 161 S stars, including 18 Tc-rich (intrinsic) stars, 19 Tc-deficient (extrinsic) ones and 124 candidates for Tc-deficient S stars, are presented in this paper. Based on some further investigations into the infrared properties of both Tc-rich and Tc-deficient S stars, 104 candidates are identified as very likely Tc-deficient S stars. The large number of infrared-selected Tc-deficient S stars provides a convenient way to study the physical properties and the evolutionary status of this species of S stars.

Key words: stars: AGB and post-AGB -- stars: evolution -- stars: circumstellar matter -- infrared: stars

Offprint request: X.-H. Wang, wang_xunhao@sina.com

SIMBAD Objects

© ESO 2002