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CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk

Gillen, E. and Aigrain, S. and Terquem, C. and Bouvier, J. and Alencar, S. H. P. and Gandolfi, D. and Stauffer, J. and Cody, A. and Venuti, L. and Viana Almeida, P. and Micela, G. and Favata, F. and Deeg, H. J. (2017) CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk. Astronomy & Astrophysics, 599 . Art. No. A27. ISSN 0004-6361.

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CoRoT 223992193 is the only known low-mass, pre-main sequence eclipsing binary that shows evidence of a circumbinary disk. The system displays complex photometric and spectroscopic variability over a range of timescales and wavelengths. Using two optical CoRoT runs from 2008 and 2011/2012 (spanning 23 and 39 days), along with infrared Spitzer 3.6 and 4.5 μm observations (spanning 21 and 29 days, and simultaneous with the second CoRoT run), we model the out-of-eclipse light curves, finding that the large scale structure in both CoRoT light curves is consistent with the constructive and destructive interference of starspot signals at two slightly different periods. Using the vsini of both stars, we interpret this as the two stars having slightly different rotation periods: the primary is consistent with synchronisation and the secondary rotates slightly supersynchronously. Comparison of the raw 2011/2012 light curve data to the residuals of our spot model in colour-magnitude space indicates additional contributions consistent with a combination of variable dust emission and obscuration. There appears to be a tentative correlation between this additional variability and the binary orbital phase, with the system displaying increases in its infrared flux around primary and secondary eclipse. We also identify short-duration flux dips preceding secondary eclipse in all three CoRoT and Spitzer bands. We construct a model of the inner regions of the binary and propose that these dips could be caused by partial occultation of the central binary by the accretion stream onto the primary star. Analysis of 15 Hα profiles obtained with the FLAMES instrument on the Very Large Telescope reveal an emission profile associated with each star. The majority of this is consistent with chromospheric emission but additional higher velocity emission is also seen, which could be due to prominences. However, half of the secondary star’s emission profiles display full widths at 10% intensity that could also be interpreted as having an accretion-related origin. In addition, simultaneous u and r-band observations obtained with the MEGACam instrument on the Canada France Hawaii Telescope reveal a short-lived u-band excess consistent with either an accretion hot spot or stellar flare. The photometric and spectroscopic variations are very complex but are consistent with the picture of two active stars possibly undergoing non-steady, low-level accretion; the system’s very high inclination provides a new view of such variability.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Gillen, E.0000-0003-2851-3070
Aigrain, S.0000-0003-1453-0574
Stauffer, J.0000-0003-3595-7382
Cody, A.0000-0002-3656-6706
Additional Information:© 2017 ESO. Received: 10 March 2016. Accepted: 12 October 2016. We thank the anonymous referee for their insightful and positive report. We thank Cathie Clarke and Stefano Facchini for helpful discussions. This work was supported in part by the UK Science and Technology Facilities Council through studentship ST/J500641/1 (EG) and grant ST/G002266 (SA). J.B. thanks CNES for partial funding on this project. S.H.P.A. acknowledges support by CNPq, CAPES and Fapemig. This work is based on observations obtained with numerous facilities: the CoRoT space mission has been developed and operated by CNES, with contributions from Austria, Belgium, Brazil, ESA (RSSD and Science Program), Germany, and Spain; the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA; ESO Telescopes at the La Silla Paranal Observatory under programme ID 088.C-0239(A); MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; and the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2013-2016) under grant agreement No. 312430 (OPTICON).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)ST/J500641/1
Science and Technology Facilities Council (STFC)ST/G002266
Centre National d'Etudes Spatiales (CNES)UNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UNSPECIFIED
Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)UNSPECIFIED
European Research Council (ERC)312430 (OPTICON)
Subject Keywords:stars: pre-main sequence / stars: variables: T Tauri, Herbig Ae/Be / stars: individual: CoRoT 223992193 / protoplanetary disks / binaries: eclipsing
Record Number:CaltechAUTHORS:20170417-101134036
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Official Citation:CoRoT 223992193: Investigating the variability in a low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk E. Gillen, S. Aigrain, C. Terquem, J. Bouvier, S. H. P. Alencar, D. Gandolfi, J. Stauffer, A. Cody, L. Venuti, P. Viana Almeida, G. Micela, F. Favata and H. J. Deeg A&A, 599 (2017) A27 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76592
Deposited By: Ruth Sustaita
Deposited On:17 Apr 2017 18:25
Last Modified:03 Oct 2019 17:02

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