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| Paper: |
Optical Outburst of a Young Star |
| Volume: |
154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop |
| Page: |
1673 |
| Authors: |
Alves, Joao; Hartmann, Lee; Briceno, Cesar; Lada, Charles J. |
| Abstract: |
We present a study of CB34V, a pre-main sequence object that has increased in brightness by ~-3.7 magnitudes in the red between November 1951 (1951.9) and February 1996 (1996.1). Our data consist of intermediate and high resolution optical spectroscopy as well as optical and near-infrared photometry (BVRIJHK). We find that the color behavior of the CB34V brightness variation is peculiar, corresponding to a gray brightening. We demonstrate that CB34V is a pre-main sequence object embedded in a small molecular cloud by 2.4 visual magnitudes. At optical wavelengths CB34V has a G5 (III-IV) spectral type and is rapidly rotating with a v sin i ~145 +/- 20 km s^{-1}. We estimate a current bolometric luminosity of 7 < LCB34V < 39 (D/kpc)^2 L_odot. If the optical light is stellar in origin, the object's position on the HR diagram implies a stellar mass of ~2 M_odot and an age of ~1 x 10^6 years. We consider two possible explanations for the observed brightening: 1) a high accretion episode (FU Orionis type); and 2) time variable extinction due to motions of the non-uniform circumstellar environment. Although we favor the latter, CB34V seems difficult to classify into any of the known types of pre-main sequence variability. Research reported herein used the 1) Multiple Mirror Telescope, a joint facility of the Smithsonian Institution and the University of Arizona; and 2) Kitt Peak National Observatory |
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