Abstract

Results from a photometric search for extrasolar planetary transits across the eclipsing binary CM Dra are presented. The TEP (Transits of Extrasolar Planets) network has observed this star since 1994, and a lightcurve with 617 hours of coverage has been obtained. The data give a complete phase coverage of the CM Dra system at each of the 3 years of observations, with a noise of less than 5 mmag. New epoch and period values for CM Dra are derived, and a low flare rate of 0.025 hr^−1 has been confirmed. The absence of periodic variations in eclipse minimum times excludes the presence of very massive planets with periods of less than a few years. The lightcurve was visually scanned for the presence of unusual events which may be indicative of transits of extrasolar planets with ’massive earth’ sizes. Six suspicious events were found which are being followed up for future transits, by planets with sizes between 1.5 and 2.5 RE (Earth Radii). However, none of these events has amplitudes compatible with planets larger than 2.5 RE. Coplanar planets larger than 2.5 RE and with orbital periods of less than 60 days can therefore be ruled out with a confidence of about 80%. Planets smaller than 1.5 RE cannot be detected in the data without a sub-noise detection algorithm. A preliminary signal detection analysis shows that there is a 50% detection confidence for 2 RE planets with a period from 10 to 30 days with the current data. This data-set demonstrates that it is possible to detect terrestrial sized planets with ground based photometry, and that strong constraints on the sizes of planets orbiting in the plane of the CM Dra system can be set (Refer to PDF file for exact formulas).

Publication Date

1998

Comments

Also archived in: arXiv: astro-ph/9806371 v1 29 Jun 1998 The TEP network wishes to thank numerous people, without whose support the acquisition of these data would have been impossible. The observations by LRD and RS at the oldest reflecting telescope still in professional use - the Crossley Telescope at Lick Observatory - were very support intensive and we thank Ellen Blue, Moira Doyle, Neil Heather, Dave Koch, and the time allocation committee at UC Santa Cruz for their support. For observations and reductions at Capilla Peak, we thank Randy Grashuis. We thank Ayvur Akalin who helped us with an implementation of the Kwee-v. Woerden algorithm. We also thank Woo-Baik Lee and Ho-Il Kim at the Korean Astronomy Observatory for helpful correspondence. The IAC80 telescope is operated at Iza˜na Observatory, Tenerife by the Instituto de Astrofisica de Canarias. We thank the University of Rochester for use of the Mees Telescope. HJD acknowledges a postdoctoral fellowship from the Rochester Institute of Technology in 1994, and later a grant ’Formaci´on de Personal Investigador’ from the Ministry for Education and Culture of Spain. The observations by LRD were supported in part by a grant from the NASA Ames Research Center Director’s Discretionary Fund. JS acknowledges funding provided by the French ’Programme National de Planetologie (CNRS)’.ISSN:1432-0746 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Article

Department, Program, or Center

School of Physics and Astronomy (COS)

Campus

RIT – Main Campus

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