Gunther, H. M. and Matt, S. P. and Schmitt, J. H. M. M. and Gudel, M. and Li, Z. Y. and Burton, D. M. (2010) The disk-bearing young star IM Lupi: X-ray properties and limits on accretion. Astronomy and Astrophysics, 519 (10). A97. ISSN 0004-6361
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Context. Classical T Tauri stars (CTTS) differ in their X-ray signatures from older pre-main sequence stars, e.g. weaklined TTS (WTTS). CTTS show a soft excess and deviations from the low-density coronal limit in the He-like triplets.
Aims. We test whether these features correlate with accretion or the presence of a disk by observing IM Lup, a diskbearing object apparently in transition between CTTS and WTTS without obvious accretion.
Methods. We analyse a Chandra grating spectrum and additional XMM-Newton data of IM Lup and accompanying
optical spectra, some of them taken simultaneously to the X-ray observations. We fit the X-ray emission lines and
decompose the H emission line in different components.
Results. In X-rays IM Lup has a bright and hot active corona, where elements of low first-ionisation potential are
depleted. The He-like Ne ix triplet is in the low-density state, but due to the small number of counts a high-density
scenario cannot be excluded on the 90% confidence level. In all X-ray properties IM Lup resembles a main-sequence
star, but it is also compatible with CTTS signatures on the 90% confidence level, thus we cannot decide if the soft
excess and deviations from the low-density coronal limit in the He-like triplets in CTTS require accretion or only the
presence of a disk. IM Lup is chromospherically active, which explains most of the emission in H. Despite its low
equivalent width, the complexity of the H line profile is reminiscent of CTTS. We present an estimate for the mass
accretion rate of 10−11M yr−1.
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|Item Type:||Article (Commonwealth Reporting Category C)|
|Item Status:||Live Archive|
|Additional Information:||© 2010 ESO. Deposited in accordance with the copyright policy of the publisher.|
|Faculty / Department / School:||Historic - Faculty of Sciences - Department of Biological and Physical Sciences|
|Date Deposited:||17 Jul 2011 05:24|
|Last Modified:||16 Oct 2014 05:32|
|Uncontrolled Keywords:||stars; formation; individual; IM Lupi; X-rays|
|Fields of Research :||02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020108 Planetary Science (excl. Extraterrestrial Geology)
02 Physical Sciences > 0204 Condensed Matter Physics > 020406 Surfaces and Structural Properties of Condensed Matter
|Socio-Economic Objective:||E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences|
|Identification Number or DOI:||doi: 10.1051/0004-6361/201014386|
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