American Astronomical Society, Astronomical Journal, (113), p. 1395, 1997
DOI: 10.1086/118354
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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 consists 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 vsini ~ 145 +/- 20 km s(-1) . We estimate a current bolometric luminosity of 7 < LCB34V < 39 (D/kpc)(2) L_sun. If the optical light is stellar in origin, the object's position on the HR diagram implies a stellar mass of ~ 2 M_sun 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.