The 2008 Extreme Outburst of the Young Eruptive Variable Star EX Lupi
Abstract
In early 2008, the young low-mass star EX Lupi, the prototype of the EXor class of eruptive variables, optically brightened by over 5 mag for a period of seven months. The previous time a change of such amplitude had been observed in EX Lup was over 50 years ago. In this Letter, we present new optical and near-IR high-resolution spectroscopy of EX Lup during the 2008 outburst. We investigate the physical characteristics of the outburst both soon after it began and some four months later, and consider the observed energetics and kinematics. Emission line strengths, widths, and profiles significantly changed between the two observations. Also, modeling of the 2.2935 μm CO overtone band head emission suggests that an inner gap in the circumstellar gas disk around the star may be present and that it is from the inner edge of the gas disk that the CO overtone emission probably arises. We derive a mass accretion luminosity and rate during the extreme outburst of ~2 ± 0.5 L_⊙ and ~(2 ± 0.5) × 10^(–7) M_⊙ yr^(–1), respectively, which suggests that this outburst was indeed one of the strongest witnessed in EX Lup, yet not as strong as those observed in FU Orionis stars.
Additional Information
© 2010 The American Astronomical Society. Received 2010 March 13; accepted 2010 June 28; published 2010 July 22. We warmly thank G.H. Herbig for providing access to the J23 HIRES data on EX Lupi. We are indebted to A. Jones for alerting us (via G.H. Herbig) to this new outburst of EX Lup. We also thank A. Juhasz for providing the K-band magnitude used above. Data were obtained at the W.M. Keck Observatory, operated as a scientific partnership by the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. B.R. acknowledges partial support from the NASA Astrobiology Institute (Cooperative Agreement No. NNA04CC08A).Attached Files
Published - Aspin2010p11226Astrophys_J_Lett.pdf
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Additional details
- Eprint ID
- 19745
- Resolver ID
- CaltechAUTHORS:20100831-133312246
- NNA04CC08A
- NASA
- Created
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2010-09-01Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- COSMOS, Infrared Processing and Analysis Center (IPAC)