Abstract
Using the Main Stellar Spectrograph of the 6-m Special Astrophysical Observatory telescope equipped with a polametric analyzer, we measured the longitudinal magnetic field component B ∥ for the T Tauri stars T Tau and AS 507 on January 16 and 18 and February 15, 2003. For both stars, we determined only the upper limits on B ∥ from photospheric lines: +15±30 G for T Tau and −70±90 G for AS 507. The magnetic field of AS 507 was not measured previously, while B ∥ for T Tau is lower than its values that we obtained in 1996 and 2002 (B ∥≂150±50G), suggesting that the longitudinal magnetic field component in the photosphere of T Tau is variable. We also measured the longitudinal magnetic field component for T Tau in the formation region of the He I 5876 Å emission line. We found B ∥ in this region to be ⋍+650, ⋍+350, and ⋍+1100 G on January 16, 18, and February 15, 2003, respectively. Our observations on January 18 and February 15 correspond to virtually the same phase of the star's rotation period, but the profiles of the He I 5876 Å line differ markedly on these two nights. Therefore, we believe that the threefold difference between the B ∥ values on these nights does not result from observational errors. We discuss the possible causes of the B ∥ variability in the photosphere and the magnetosphere of T Tau.
Similar content being viewed by others
References
S. H. P. Alencar and C. Batalha, Astrophys. J. 571, 378 (2002).
H. W. Babcock, Astrophys. J., Suppl. Ser. 3, 207 (1958).
C. Bertout, Ann. Rev. Astron. Astrophys. 27, 351 (1998).
P. F. Chugainov, G. V. Zaitseva, and M. N. Lovkaya, Pis'ma Astron. Zh. 21, 51 (1995) [Astron. Lett. 21, 457 (1995)].
G. A. Chuntonov, Annu. Rep. Spec. Astrophys. Obs. 56, 36 (1997).
E. Guenther, H. Lehmann, J. P. Emerson, and J. Staude, Astron. Astrophys. 341, 768 (1999).
G. H. Herbig, Astrophys. J. 214, 747 (1977).
G. H. Herbig and K. R. Bell, Lick Observ. Bull. 1111 (1988).
W. Herbst, J. F. Booth, P. F. Chugainov, et al., Astrophys. J. 310, 71 (1986).
C. M. Johns-Krull, J. A. Valenti, A. P. Hatzes, and A. Kanaan, Astrophys. J. 510, L41 (1999a).
C. M. Johns-Krull, J. A. Valenti, and C. Koresko, Astrophys. J. 516, 900 (1999b).
C. M. Johns-Krull, J. Valenti, S. H. Saar, and A. P. Hatzes, ASP Conf. Ser. 223, 521 (2001).
F. Kupka, N. Piskunov, and T. A. Ryabchikova, Astron. Astrophys., Suppl. Ser. 138, 119 (1999).
V. E. Panchyuk, Preprint No. 154 (Spets. Astrofiz. Obs., 2001).
D. L. Padgett, Astrophys. J. 471, 847 (1996).
D. A. Smirnov, S. N. Fabrika, S. A. Lamzin, and G. G. Valyavin, Astron. Astrophys. 401, 1057 (2003).
R. J. White and A. M. Ghez, Astrophys. J. 556, 265 (2001).
Author information
Authors and Affiliations
Additional information
__________
Translated from Pis'ma v Astronomicheski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \) Zhurnal, Vol. 30, No. 7, 2004, pp. 506–510.
Original Russian Text Copyright © 2004 by Smirnov, Lamzin, Fabrika, Chuntonov.
Rights and permissions
About this article
Cite this article
Smirnov, D.A., Lamzin, S.A., Fabrika, S.N. et al. Possible variability of the magnetic field of T Tau. Astron. Lett. 30, 456–460 (2004). https://doi.org/10.1134/1.1774397
Received:
Issue Date:
DOI: https://doi.org/10.1134/1.1774397