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An extrasolar planet that transits the disk of its parent star

Konacki, Maciej and Torres, Guillermo and Jha, Saurabh and Sasselov, Dimitar D. (2003) An extrasolar planet that transits the disk of its parent star. Nature, 421 (6922). pp. 507-509. ISSN 0028-0836.

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Planets orbiting other stars could in principle be found through the periodic dimming of starlight as a planet moves across—or 'transits'—the line of sight between the observer and the star. Depending on the size of the planet relative to the star, the dimming could reach a few per cent of the apparent brightness of the star. Despite many searches, no transiting planet has been discovered in this way; the one known transiting planet—HD209458b—was first discovered using precise measurements of the parent star's radial velocity and only subsequently detected photometrically. Here we report radial velocity measurements of the star OGLE-TR-56, which was previously found to exhibit a 1.2-day transit-like light curve in a survey looking for gravitational microlensing events. The velocity changes that we detect correlate with the light curve, from which we conclude that they are probably induced by an object of around 0.9 Jupiter masses in an orbit only 0.023 au from its star. We estimate the planetary radius to be around 1.3 Jupiter radii and its density to be about 0.5 g cm^(-3). This object is hotter than any known planet (approx 1,900 K), but is still stable against long-term evaporation or tidal disruption.

Item Type:Article
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URLURL TypeDescription ReadCube access
Torres, Guillermo0000-0002-5286-0251
Sasselov, Dimitar D.0000-0001-7014-1771
Additional Information:© 2003 Nature Publishing Group. Received 27 November 2002; Accepted 30 December 2002. We thank A. Udalski and the OGLE team for generous contributions to this project. We are very grateful to S. Kulkarni for support, to R. Noyes and D. Latham for comments, to T. Barlow for assistance with the spectroscopic reductions using the MAKEE Keck Observatory HIRES DataReduction Software ( and to K. Stanek for his encouragement. The data presented here were obtained at the W.M. Keck Observatory (operated by Caltech, the University of California, and NASA), which was made possible by the generous financial support of the W. M. Keck Foundation. M.K. gratefully acknowledges the support of NASA through the Michelson Fellowship programme. G.T. acknowledges support from NASA’s Kepler Mission. S.J. thanks the Miller Institute for Basic Research in Science at UC Berkeley for support via a research fellowship.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
NASA Michelson FellowshipUNSPECIFIED
Miller Institute for Basic Research in ScienceUNSPECIFIED
Issue or Number:6922
Record Number:CaltechAUTHORS:20150401-115903703
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Official Citation:An extrasolar planet that transits the disk of its parent star p507 Maciej Konacki, Guillermo Torres, Saurabh Jha and Dimitar D. Sasselov doi:10.1038/nature01379
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56288
Deposited By: Ruth Sustaita
Deposited On:01 Apr 2015 19:14
Last Modified:09 Mar 2020 13:19

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