EDP Sciences
Free Access
Volume 410, Number 1, October IV 2003
Page(s) 269 - 282
Section Stellar atmospheres
DOI https://doi.org/10.1051/0004-6361:20031242

A&A 410, 269-282 (2003)
DOI: 10.1051/0004-6361:20031242

The short period multiplicity among T Tauri stars

C. H. F. Melo

European Southern Observatory, Casilla 19001, Santiago 19, Chile Observatoire de Genève, Ch. des Maillettes 51, 1290 Sauverny, Switzerland
(Received 11 December 2002 / Accepted 30 July 2003 )

We present the results of high-resolution spectroscopic observations carried out over three years aimed at estimating the short-period ( $P_{\rm orb}<100$ days) binary frequency of a sample of T Tauri stars in Oph-Sco, Cha, Lup, CrA star forming regions (SFRs), already observed with high angular resolution techniques by Ghez et al. (1993) and by Ghez et al. (1997) to detect wider components. When combining all four SFRs, the short-period binary frequency is indistinguishable from that found by Duquennoy & Mayor (1991) for the solar-type field stars which is also consistent with the previous result obtained by Mathieu (1992, 1994). When Oph-Sco is analyzed separately, it seems that there is an excess of short-period binaries of a factor 2-2.5. On the contrary, short-period binary systems seem to be absent in the sample containing stars in Cha/Lup/CrA. Such a trend was equally found by Mathieu (1992) in Taurus. An excess of spectroscopic systems among the components of visual multiple systems is also observed.

Key words: stars: binaries: close -- stars: formation

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