AAS 203rd Meeting, January 2004
Session 33 Young Stars
Oral, Monday, January 5, 2004, 2:00-3:30pm, Regency VII

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[33.02] Short Time-Scale Variations of the UXOR Candidate V3798 Sgr

V. Strelnitski (Maria Mitchell Obs.), J. D. R. Steinfadt (U. of Arizona and Maria Mitchell Obs.)

Previous observations have shown that V3798 Sgr undergoes erratic light declines with the time scales from years down to days; this allowed for tentative classification of this variable as an UXOR - small group of pre-main sequence stars demonstrating erratic light declines on these time scales. We report on a much faster, only a half-hour, dimming of V3798 Sgr observed in June 2003, during our multicolor, CCD monitoring of this star. The dimming was observed in all the (B, V, R, an I) colors, ranging in amplitude from 0.35 magnitude in B to 0.15 magnitude in I. Such a short time scale, together with the previously observed longer time scales, makes V3798 Sgr a difficult case for classification, because it combines the variability properties of UXOR's and classical T Tau stars. This short time scale also excludes explanations of dimming based on obscuration by dust clouds in a rotating disk or shell. Sudden dust precipitation in a dense (>1011 \rm cm-3), expanding blob of stellar wind is more plausible. This project was supported by the NSF/REU grant AST-0097694 and the Nantucket Maria Mitchell Association.

The author(s) of this abstract have provided an email address for comments about the abstract: vladimir@mmo.org

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.