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| EPoS Contribution |
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On the 2008 outburst of EX Lup - Mechanism of the outburst and turbulent mixing of solids
Attila Juhasz Leiden Observatory, Leiden, The Netherlands | |
| EX Lup, the prototype of EXor class of eruptive young stars, went into its most recent outburst in 2008. This outburst was followed with ground based telescopes as well as with the Spitzer Space Telescope. We modeled the spectral energy distribution (SED) of EX Lup in the outburst from optical to millimeter wavelengths with a 2D radiative transfer code. We found that 80-100% of the accretion luminosity is radiated away in the form of a 6700K blackbody emission which dominates the SED at optical wavelengths. The SED can be modeled without an optically thick accretion disk. In the case of thermal instability, the currently accepted model of EXor outburst, such disk is the dominant radiation source during the outburst. We concluded, therefore, that the 2008 outburst of EX Lup was not triggered by thermal instability. Mid-infrared spectral observation with MIDI/VLTI show the presence of large grains in the disk atmosphere of EX Lup which were not present in the pre-outburst phase. Spitzer IRS spectra of EX Lup revealed that nine months after the end of the outburst the crystallinity in the 10 micron feature complex decreased. Our modeling suggests that large grains are likely to be stirred up by turbulent mixing, which was stronger in the outburst than in the quiescent. Vertical mixing is, however, unlikely to be cause of the decrease of the crystallinity in the mid-infrared spectra. | |
| Collaborators: P. Abraham, Konkoly Observatory, Hungary R. van Boekel, MPIA, Germany C.P. Dullemond, MPIA, Germany J. Bouwman, MPIA, Germany A. Kospal, Leiden Observatory, The Netherlands A. Sicilia-Aguilar, MPIA, Germany Th. Henning, MPIA, Germany L. Mosoni, Konkoly Observatory, Hungary Zs. Regaly, Konkoly Observatory, Hungary |
Suggested Session:
Early Phases of Disks |