Rhee, Joseph H. and Song, Inseok and Zuckerman, B. (2008) Warm dust in the terrestrial planet zone of a Sun-like Pleiades star: Collisions between planetary embryos? Astrophysical Journal, 675 (1). pp. 777-783. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20090505-075320253
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Only a few solar-type main-sequence stars are known to be orbited by warm dust particles; the most extreme is the G0 field star BD +20 307 that emits ~4% of its energy at mid-infrared wavelengths. We report the identification of a similarly dusty star HD 23514, an F6-type member of the Pleiades. A strong mid-IR silicate emission feature indicates the presence of small warm dust particles, but with the primary flux density peak at the nonstandard wavelength of ~9 μm. The existence of so much dust within an AU or so of these stars is not easily accounted for given the very brief lifetime in orbit of small particles. The apparent absence of very hot (≳1000 K) dust at both stars suggests the possible presence of a planet closer to the stars than the dust. The observed frequency of the BD +20 307/HD 23514 phenomenon indicates that the mass equivalent of Earth's Moon must be converted, via collisions of massive bodies, to tiny dust particles that find their way to the terrestrial planet zone during the first few hundred million years of the life of many (most?) Sun-like stars. Identification of these two dusty systems among youthful nearby solar-type stars suggests that terrestrial planet formation is common.
|Additional Information:||© 2008 The American Astronomical Society. Received 2007 August 10; accepted 2007 October 18. We thank A. Weinberger and E. E. Becklin for permission to use some Michelle data obtained during a joint Keck time exchange observing run, and E. Rice for assistance in obtaining the NIRSPEC spectrum. We also thank S. Kenyon and C. Lisse each for a helpful discussion and are grateful to C. H. Chen for providing a Spitzer IRS spectrum of η Corvi. We appreciate the constructive comments of the referee. Based on observations (GN-2006A-Q-39 and GN-2006B-DD-5) obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and SECYT (Argentina). This research was supported in part by NASA grants to UCLA. This research has made use of the VizieR and of data products from the Two Micron All Sky Survey.|
|Subject Keywords:||circumstellar matter; infrared : stars; open clusters and associations : individual (Pleiades) planetary systems : formation; stars : individual (HD 23514)|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||11 May 2009 21:04|
|Last Modified:||26 Dec 2012 10:59|
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