Stable and unstable accretion in the classical T Tauri stars IM Lup and RU Lup as observed by MOST

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dc.creator Siwak, Michal
dc.creator Ogloza, Waldemar
dc.creator Rucinski, Slavek M.
dc.creator Moffat, Anthony F. J.
dc.creator Matthews, Jaymie M.
dc.creator Cameron, Chris
dc.creator Guenther, David B.
dc.creator Kuschnig, Rainer
dc.creator Rowe, Jason F.
dc.creator Sasselov, Dimitar
dc.date.accessioned 2018-01-24T14:06:43Z
dc.date.available 2018-01-24T14:06:43Z
dc.date.issued 2016-03-11
dc.identifier.issn 0035-8711
dc.identifier.uri http://library2.smu.ca/handle/01/27253
dc.description Publisher's Version/PDF
dc.description.abstract Results of the time variability monitoring of the two classical T Tauri stars, RU Lup and IM Lup, are presented. Three photometric data sets were utilized: (1) simultaneous (same field) MOST satellite observations over four weeks in each of the years 2012 and 2013, (2) multicolour observations at the South African Astronomical Observatory in April–May of 2013, (3) archival V-filter All Sky Automated Survey (ASAS) data for nine seasons, 2001– 2009. They were augmented by an analysis of high-resolution, public-domain VLT-UT2 Ultraviolet Visual Echelle Spectrograph spectra from the years 2000 to 2012. From the MOST observations, we infer that irregular light variations of RU Lup are caused by stochastic variability of hotspots induced by unstable accretion. In contrast, the MOST light curves of IM Lup are fairly regular and modulated with a period of about 7.19–7.58 d, which is in accord with ASAS observations showing a well-defined 7.247 [plus or minus] 0.026 d periodicity. We propose that this is the rotational period of IM Lup and is due to the changing visibility of two antipodal hotspots created near the stellar magnetic poles during the stable process of accretion. Reanalysis of RU Lup high-resolution spectra with the broadening function approach reveals signs of a large polar coldspot, which is fairly stable over 13 years. As the star rotates, the spot-induced depression of intensity in the broadening function profiles changes cyclically with period 3.710 58 d, which was previously found by the spectral cross-correlation method. en_CA
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dc.description.provenance Made available in DSpace on 2018-01-24T14:06:43Z (GMT). No. of bitstreams: 1 Guenther_David_B_article_2016b.pdf: 2769176 bytes, checksum: 6534e7a1d321463543605f5bfa3314d8 (MD5) Previous issue date: 2016 en
dc.language.iso en en_CA
dc.publisher Oxford University Press en_CA
dc.relation.uri https://dx.doi.org/10.1093/mnras/stv2848
dc.rights This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
dc.subject.lcsh Accretion (Astrophysics)
dc.subject.lcsh T Tauri stars
dc.title Stable and unstable accretion in the classical T Tauri stars IM Lup and RU Lup as observed by MOST en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Monthly Notices of the Royal Astronomical Society 456(4), 3972-3984. (2016) en_CA
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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
 
Published Version: https://dx.doi.org/10.1093/mnras/stv2848
 
 

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