A long-term photometric study of V 1184 Tauri

¹ Institute of Astronomy, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose blvd., 1784 Sofia, Bulgaria e-mail: esemkov@astro.bas.bg
² Sternwarte Sonneberg, Sternwartestr. 32, 96515 Sonneberg, Germany
³ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
⁴ Zentrum für Astronomie Heidelberg, Landessternwarte, Königstuhl 12, 69117 Heidelberg, Germany
⁵ Kiso Observatory, Institute of Astronomy, School of Science, the University of Tokyo, Mitake-mura, Kiso-gun, Nagano-ken 397-0101, Japan

Received: 14 December 2007
Accepted: 21 February 2008

Abstract

Aims. The main purpose of our investigation is to construct the long-time light curve of the PMS star V 1184 Tau. We consider the study of the photometrical variability of PMS stars as very important for understanding stellar evolution. The unusual photometric variability of V 1184 Tau was reported in previous studies as well, but the nature of the observed deep minima is still under discussion.

Methods. We present recent data from CCD photometry and from archival photographic plates. The photometric BVRI data presented in this paper were collected from November 2005 to November 2007. To construct the historical light curve of V 1184 Tau, a search for archived photographic observations in the Wide-Field Plate Database (WFPDB) was made. As a result, 412 photographic plates were found containing the field of V 1184 Tau. A part of the plates were scanned at our request and a magnitude estimation was made of V 1184 Tau.

Results. Our recent photometric data suggest that the star brightness is still near the minimum. Thus the period of strong light variations that started in 2003 continues up to the present, hence more than 4 years. Our data from the archival photographic plates suggest that an unknown minimum of brightness exists in the approximate period 1980-1985. Taking all available photometric and spectroscopic data into account we must reject the hypothesis that V 1184 Tau is an FU Orionis type object. V 1184 Tau is a G type low-mass star whose spectrum is similar to WTT stars, but its photometric behavior is typical of the UX Orionis variable stars. Assuming the obscuration from orbiting dust clouds as a reason for a deep minimum, we estimate the approximate period of obscurations and the interval between two deep minima. Our calculations give a 25-28 year period between the two minima and approximately 8-10 year duration of the minima.