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An HST Imaging Survey of Low-mass Stars in the Chamaeleon I Star-forming Region

Robberto, M. and Spina, L. and Da Rio, N. and Apai, D. and Pascucci, I. and Ricci, L. and Goddi, C. and Testi, L. and Palla, F. and Bacciotti, F. (2012) An HST Imaging Survey of Low-mass Stars in the Chamaeleon I Star-forming Region. Astronomical Journal, 144 (3). Art. No. 83. ISSN 0004-6256. doi:10.1088/0004-6256/144/3/83.

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We present new Hubble Space Telescope/WFPC2 observations of 20 fields centered around T Tauri stars in the Chamaeleon I star-forming region. Images have been obtained in the F631N ([OI] λ6300), F656N (Hα), and F673N ([S II] λλ6716, 6731) narrow-band filters, plus the Johnson V-band equivalent F547M filter. We detect 31 T Tauri stars falling within our fields. We discuss the optical morphology of 10 sources showing evidence of either binarity, circumstellar material, or mass loss. We supplement our photometry with a compilation of optical, infrared, and submillimeter (sub-mm) data from the literature, together with new sub-mm data for three objects, to build the spectral energy distributions (SEDs) of 19 single sources. Using an SED model fitting tool, we self-consistently estimate a number of stellar and disk parameters, while mass accretion rates are directly derived from our Hα photometry. We find that bolometric luminosities derived from dereddened optical data tend to be underestimated in systems with high α_(2-24) IR spectral index, suggesting that disks seen nearly edge-on may occasionally be interpreted as low-luminosity (and therefore more evolved) sources. On the other hand, the same α_(2-24) IR spectral index, a tracer of the amount of dust in the warmer layers of the circumstellar disks, and the mass accretion rate appear to decay with the isochronal stellar age, suggesting that the observed age spread (≃0.5-5 Myr) within the cluster is real. Our sample contains a few outliers that may have dissipated their circumstellar disks on a shorter timescale.

Item Type:Article
Related URLs:
URLURL TypeDescription
Apai, D.0000-0003-3714-5855
Pascucci, I.0000-0001-7962-1683
Testi, L.0000-0003-1859-3070
Additional Information:© 2012 American Astronomical Society. Received 2011 August 31; accepted 2012 April 16; published 2012 August 10. The authors thank Kevin Luhman for discussions and contribution to the source selection process and Basmah Riaz for early analysis of SED fitting. Support for program 11983 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract. NAS 5-26555.
Funding AgencyGrant Number
NASANAS 5-26555
Subject Keywords:open clusters and associations: individual (Chamaeleon I); stars: luminosity function, mass function; stars: pre-main sequence
Issue or Number:3
Record Number:CaltechAUTHORS:20120928-155056669
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Official Citation:An HST Imaging Survey of Low-mass Stars in the Chamaeleon I Star-forming Region M. Robberto et al. 2012 The Astronomical Journal 144 83
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34555
Deposited By: Ruth Sustaita
Deposited On:02 Oct 2012 15:05
Last Modified:09 Nov 2021 23:09

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