Bibcode
Sipos, N.; Ábrahám, P.; Acosta-Pulido, J.; Juhász, A.; Kóspál, Á.; Kun, M.; Moór, A.; Setiawan, J.
Bibliographical reference
Astronomy and Astrophysics, Volume 507, Issue 2, 2009, pp.881-889
Advertised on:
11
2009
Journal
Citations
55
Refereed citations
52
Description
Aims: EX Lupi is the prototype of EXors, a subclass of low-mass pre-main
sequence stars whose episodic eruptions are attributed to temporarily
increased accretion. In quiescence the optical and near-infrared
properties of EX Lup cannot be distinguished from those of normal T Tau
stars. Here we investigate whether it is the circumstellar disk
structure that makes EX Lup an atypical Class II object. During outburst
the disk might undergo structural changes. Our characterization of the
quiescent disk is intended to serve as a reference for studying the
physical changes related to one of EX Lupi's strongest known eruptions
in 2008 Jan-Sep. Methods: We searched the literature for
photometric and spectroscopic observations including ground-based, IRAS,
ISO, and Spitzer data. After constructing the optical-infrared spectral
energy distribution (SED), we compared it with the typical SEDs of other
young stellar objects and modeled it using the Monte Carlo radiative
transfer code RADMC. We determined the mineralogical composition of the
10 μm silicate emission feature and also gave a description of the
optical and near-infrared spectra. Results: The SED is similar
to that of a typical T Tauri star in most aspects, though EX Lup emits
higher flux above 7 μm. The quiescent phase data suggest low-level
variability in the optical-mid-infrared domain. By integrating the
optical and infrared fluxes, we derived a bolometric luminosity of 0.7
L&sun;. The 10 μm silicate profile could be fitted by a
mixture consisting of amorphous silicates, but no crystalline silicates
were found. A modestly flaring disk model with a total mass of 0.025
M&sun; and an outer radius of 150 AU was able to reproduce
the observed SED. The derived inner radius of 0.2 AU is larger than the
sublimation radius, and this inner gap sets EX Lup apart from typical T
Tauri stars.
Full Table 3 is only available in electronic form at the CDS via
anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/507/881
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