EDP Sciences
Free access
Volume 401, Number 3, April III 2003
Page(s) 1057 - 1061
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20030156

A&A 401, 1057-1061 (2003)
DOI: 10.1051/0004-6361:20030156

Possible detection of a magnetic field in T Tauri

D. A. Smirnov1, 2, S. N. Fabrika3, S. A. Lamzin1, 2 and G. G. Valyavin3

1  Sternberg Astronomical Institute, Moscow V-234 119992, Russia
2  Isaak Newton Institute of Chile Branch in Moscow, Russia
3  Special Astrophysical Observatory, Nizhnij Arkhyz 357147, Russia

(Received 24 June 2002 / Accepted 6 January 2003)

Medium-resolution $(R\simeq 15\,000)$ circular spectropolarimetry of T Tauri is presented. The star was observed twice: on November 11, 1996 and January 22, 2002. Weak circular polarization was found in photospheric absorption lines, indicating a mean surface longitudinal magnetic field $B_{\Vert}$ of $160\pm 40$ G and $140\pm 50$ G at the epoch of the first and second observations respectively. While these values are near the detection limit of our apparatus, we belive that they are real. One can conclude from our data that $B_{\Vert}$ of T Tau does not significantly exceed 200 G, which is much less than surface magnetic field strength of the star ( >2.3 kG) found by Guenther et al. (1999) and Johns-Krull et al. (2000). We discuss possible reasons for this difference.

Key words: stars: pre-main sequence -- stars: magnetic fields -- stars: individual: T Tau

Offprint request: D. Smirnov, danila@sai.msu.ru

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