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Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis

Deeg, H. J. and Ocaña, B. and Kozhevnikov, V. P. and Charbonneau, D. and O'Donovan, F. T. and Doyle, L. R. (2008) Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis. Astronomy and Astrophysics, 480 (2). pp. 563-571. ISSN 0004-6361. doi:10.1051/0004-6361:20079000.

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Aims. Our objective is to elucidate the physical process that causes the observed observed-minus-calculated (O-C) behavior in the M4.5/ M4.5 binary CM Dra and to test for any evidence of a third body around the CM Dra system. Methods. New eclipse minimum timings of CM Dra were obtained between the years 2000 and 2007. The O-C times of the system are fitted against several functions, representing different physical origins of the timing variations. Results. Using our observational data in conjunction with published timings going back to 1977, a clear non-linearity in O-C times is apparent. An analysis using model-selection statistics gives about equal weight to a parabolic and to a sinusoidal fitting function. Attraction from a third body, either at large distance in a quasi-constant constellation across the years of observations or from a body on a shorter orbit generating periodicities in O-C times is the most likely source of the observed O-C times. The white dwarf GJ 630.1B, a proper motion companion of CM Dra, can however be rejected as the responsible third body. Also, no further evidence of the short-periodic planet candidate described by Deeg et al. (2000, A&A, 358, L5) is found, whereas other mechanisms, such as period changes from stellar winds or Applegate's mechanism can be rejected. Conclusions. A third body, being either a few-Jupiter-mass object with a period of 18.5 ± 4.5 years or an object in the mass range of 1.5 M-jup to 0.1 M☉ with periods of hundreds to thousands of years is the most likely origin of the observed minimum timing behavior.

Item Type:Article
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Charbonneau, D.0000-0002-9003-484X
O'Donovan, F. T.0000-0002-4858-6106
Additional Information:© ESO 2008. Received 5 November 2007 / Accepted 28 December 2007. Some of the observations published in this article were made with the IAC80 telescope operated by the Instituto de Astrofísica de Tenerife in the Observatorio del Teide, and with the INT telelescope operated by the Isaac Newtown Group of Telescopes in the Observatorio del Roque de los Muchachos. This research was supported by Grant ESP2004-03855-C03-03 of the Spanish Education and Science Ministry. Some material presented here is based on work supported by NASA under the grant NNG05GJ29G, issued through the Origins of Solar Systems Program.
Funding AgencyGrant Number
Ministerio de Educación y Ciencia (Spain)ESP2004-03855-C03-03
Subject Keywords:stars: individual: CM Dra; stars: binaries: eclipsing; eclipses; stars: planetary systems
Issue or Number:2
Record Number:CaltechAUTHORS:DEEaanda08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13277
Deposited By: Tony Diaz
Deposited On:11 Feb 2009 04:38
Last Modified:08 Nov 2021 22:36

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