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The low-mass diskless population of Corona Australis

López Martí, B. and Spezzi, L. and Merín, B. and Morales-Calderón, M. and Bouy, H. and Barrado y Navascués, D. and Eislöffel, J. (2010) The low-mass diskless population of Corona Australis. Astronomy and Astrophysics, 515 . Art. No. A31. ISSN 0004-6361.

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We combine published optical and near-infrared photometry to identify new low-mass candidate members in an area of about 0.64 deg^2 in Corona Australis with the S-parameter method. Five new candidate members of the region are selected. They have estimated ages between 3 and 15 Myr and masses between 0.05 and 0.15 M_⊙. With Spitzer photometry we confirm that these objects are not surrounded by optically thick disks. However, one of them is found to display excess at 24 μm, thus suggesting it harbors a disk with an inner hole. With an estimated mass of 0.07 M_⊙ according to the SED fitting, this is one of the lowest-mass objects reported to possess a transitional disk. Including these new members, the fraction of disks is about 50% among the total Corona Australis population selected by the same criteria, lower than the 70% fraction reported earlier for this region. Even so, we find a ratio of transitional to primordial disks (45%) very similar to the value derived by previous authors. This ratio is higher than for solar-type stars (5–10%), suggesting that disk evolution is faster in the latter, and/or that the “transitional disk” stage is not such a short-lived step for very low-mass objects. However, this impression needs to be confirmed with better statistics.

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Additional Information:© ESO 2010. Received 23 November 2009. Accepted 12 March 2010. We are very grateful to F. Comerón for his help with the data analysis and his comments on an early draft of this paper. We also thank A. Bayo for useful discussions. This work was partially funded by the Spanish MICINN through grants Consolider-CSD2006-00070 and ESP2007-65475-C02-02. It also had funding from the Madrid regional government through grant CAM/PRICIT-S2009ESP- 1496. This research is based on observations collected at the European Southern Observatory, on La Silla (Chile), and on data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. It also used observations made with the Spitzer Space Telescope, operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This publication greatly benefited of the use of the SIMBAD database and VIZIER catalogue service, both operated at CDS (Strasbourg, France). We used the VO-compliant tools Aladin, developed at CDS, TOPCAT, currently developed within the AstroGrid project, and VOSA, developed under the Spanish Virtual Observatory project, and supported by the Spanish MICINN through grant AyA2008-02156.
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Ministerio de Ciencia e Innovación (MCINN)Consolider-CSD2006-00070
Ministerio de Ciencia e Innovación (MCINN)Consolider-ESP2007-65475-C02-02
Madrid regional governmentCAM/PRICIT-S2009ESP-1496
Subject Keywords:stars: low-mass – stars: formation – stars: pre-main sequence – stars: luminosity function, mass function
Record Number:CaltechAUTHORS:20100628-083806243
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18824
Deposited By: Tony Diaz
Deposited On:05 Aug 2010 22:36
Last Modified:03 Oct 2019 01:48

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