Astron. Astrophys. 326, 211-217 (1997)

T Tauri stars and the Gould Belt near Lupus ^*

R. Wichmann ¹, M. Sterzik ², J. Krautter ², A. Metanomski ^{1, 3} and W. Voges <sup>2

1</sup> Landessternwarte Königstuhl, D-69117 Heidelberg, Germany
² Max-Plank-Institut für Extraterrestrische Physik, D-85740 Garching, Germany
³ European Southern Observatory, La Silla, Chile

Received 2 December 1996 / Accepted 29 January 1997

Abstract

We present results of a study to investigate the spatial distribution of X-ray active young stellar objects near the Lupus star forming region (SFR). In this SFR, a recent study has led to the discovery of some 130 new weak-line T Tauri stars (WTTS) dispersed over a large area of some 230 square degrees. However, the true extent of the spatial distribution of these stars could not be determined in this study.

We have selected from the ROSAT All-Sky-Survey candidate T Tauri stars within a narrow strip of width, located adjacent to the Lupus SFR, and oriented perpendicular to the galactic plane. Intermediate resolution spectroscopy was carried out to identify stellar objects with strong Li I absorption, indicative of their youth, and 48 Li-rich stars were found within our study region.

The peak at in the spatial distribution of Li-rich stars within this strip corresponds well with the intersection of our study region with the Gould Belt, but is inconsistent with the assumption that these stars belong to a galactic ZAMS foreground population, which would be expected to be centered on the galactic midplane.

We conclude that the majority of recently discovered low-mass, X-ray active, Li-rich stars dispersed over large areas around Gould Belt SFRs are indeed WTTS with ages not exceeding that of the Gould Belt itself, i.e. below years.

Key words: stars: formation stars: late-type stars: pre-main sequence X-rays: stars

* Based on observations collected at European Southern Observatory, Chile (observing proposals ESO 57.E-0721).

Send offprint requests to: R. Wichmann

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Contents

• 1. Introduction
• 2. Source selection
• 3. Observations
• 4. Results
  • 4.1. Lithium equivalent widths
  • 4.2. Spatial distribution
  • 4.3. Comparison with previous work
• 5. Discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: April 20, 1998
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