Issue |
A&A
Volume 562, February 2014
|
|
---|---|---|
Article Number | A50 | |
Number of page(s) | 19 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/201322493 | |
Published online | 05 February 2014 |
CoRoT 223992193: A new, low-mass, pre-main sequence eclipsing binary with evidence of a circumbinary disk⋆
1
Sub-department of Astrophysics, Department of Physics, University
of Oxford, Keble
Road, Oxford
OX1 3RH,
UK
e-mail: ed.gillen@astro.ox.ac.uk
2
School of Physics and Astronomy, Raymond and Beverly Sackler,
Faculty of Exact Sciences, Tel Aviv University, 69978
Tel Aviv,
Israel
3
UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et
d’Astrophysique de Grenoble (IPAG) UMR 5274, 38041
Grenoble,
France
4
Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA, UK
5
Departamento de Física – ICEx – UFMG, Av. Antônio Carlos, 6627, 30270-901
Belo Horizonte, MG, Brazil
6
Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
7
European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748
Garching bei München,
Germany
8
Spitzer Science Center, California Institute of
Technology, 1200 E California
Blvd., Pasadena,
CA
91125,
USA
9
Observatoire de Genève, Université de Genève,
Chemin des Maillettes 51,
1290
Sauverny,
Switzerland
10
Centro de Astrobiología (INTA-CSIC); ESAC Campus, PO Box
78, 28691
Villanueva de la Canada,
Spain
11
European Space Agency, 8–10 rue Mario Nikis, 75738
Paris Cedex 15,
France
12
INAF – Osservatorio Astronomico di Palermo,
Piazza del Parlamento 1,
90134
Palermo,
Italy
Received:
15
August
2013
Accepted:
10
November
2013
We present the discovery of CoRoT 223992193, a double-lined, detached eclipsing binary, comprising two pre-main sequence M dwarfs, discovered by the CoRoT space mission during a 23-day observation of the 3 Myr old NGC 2264 star-forming region. Using multi-epoch optical and near-IR follow-up spectroscopy with FLAMES on the Very Large Telescope and ISIS on the William Herschel Telescope we obtain a full orbital solution and derive the fundamental parameters of both stars by modelling the light curve and radial velocity data. The orbit is circular and has a period of 3.8745745 ± 0.0000014 days. The masses and radii of the two stars are 0.67 ± 0.01 and 0.495 ± 0.007 M⊙ and 1.30 ± 0.04 and 1.11-0.05+0.04 R⊙, respectively. This system is a useful test of evolutionary models of young low-mass stars, as it lies in a region of parameter space where observational constraints are scarce; comparison with these models indicates an apparent age of ~3.5–6 Myr. The systemic velocity is within 1σ of the cluster value which, along with the presence of lithium absorption, strongly indicates cluster membership. The CoRoT light curve also contains large-amplitude, rapidly evolving out-of-eclipse variations, which are difficult to explain using starspots alone. The system’s spectral energy distribution reveals a mid-infrared excess, which we model as thermal emission from a small amount of dust located in the inner cavity of a circumbinary disk. In turn, this opens up the possibility that some of the out-of-eclipse variability could be due to occultations of the central stars by material located at the inner edge or in the central cavity of the circumbinary disk.
Key words: binaries: eclipsing / stars: pre-main sequence / binaries: spectroscopic / stars: individual: CoRoT 223992193 / open clusters and associations: individual: NGC 2264 / protoplanetary disks
© ESO, 2014
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