Previous abstract Next abstract

Session 79 - Special Objects in the Galaxy.
Oral session, Thursday, June 11

[79.07] Recent Outbursts of EXORs

G. S. Stringfellow (CASA, University of Colorado), T. Kato, D. Nogami (Kyoto University), A. Landolt (Louisiana State University), D. Calzetti (STScI), S. Laurent-Muehleisen (LLNL)

EXORs, named after the prototype EX Lupi, are a unique subclass of extreme classical T Tauri stars (CTTSs) that experience major UV-optical outbursts. These outbursts, which are believed to be driven by the accretion of matter onto the star from a circumstellar disk, can range up to 5 magnitudes in amplitude visually. We have been monitoring the majority of EXORs over the last few years and have made photometric and spectroscopic observations of several during outburst, and their return to the quiescent state. Our data indicate that large variations in brightness can occur on short time scales during outburst, and that the recurrence time scales between outbursts at times may be short. We present optical photometric light curves and spectra of several EXORs in outburst, and discuss the physics inferred from the data. Insight into the accretion process that drives the outbursts, and the potential impact upon the circumstellar environment will be presented.

Program listing for Thursday