Astron. Astrophys. 333, 613-618 (1998)

Research Note

Infrared study of the two categories of S stars

P.S. Chen ^{1, 2}, X.H. Wang ^{1, 2} and G.Z. Xiong <sup>1, 2

1</sup> Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming 650011, P.R. China (ynao@public.km.yn.cn)
² United Laboratory for Optical Astronomy, Chinese Academy of Sciences, P.R. China

Received 30 January 1997 / Accepted 5 January 1998

Abstract

Photometric observations of 20 Tc-deficient and 24 Tc-rich S stars in the near infrared are presented in this paper. With the IRAS data, infrared two color diagrams, IRAS low-resolution spectra and energy distributions are discussed to summarize the way to segregate Tc-rich stars from Tc-deficient ones.

Key words: circumstellar matter stars: evolution stars: AGB, post AGB infrared: stars

Send offprint requests to: P.S. Chen

SIMBAD Objects

Contents

• 1. Introduction
• 2. Sample and observation
• 3. Color - color diagram
• 4. The LRS classification
• 5. Energy distribution
• 6. Individual samples
• 7. Summary and conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: April 20, 1998
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