The TEP Network - A Search for Transits of Extrasolar Planets: Observations of CM Draconis in 1994

Deeg, H.-J.; Martin, E.; Schneider, J.; Chevreton, M.; Doyle, L. R.; Jenkins, J. M.; Palaiologou, E.; Lee, W.-B.; Kim, H.-I.
Bibliographical reference

Astronomical and Astrophysical Transactions, vol. 13, Issue 3, pp.233-243

Advertised on:
1997
Number of authors
9
IAC number of authors
1
Citations
7
Refereed citations
6
Description
The TEP (Transits of Extrasolar Planets) network undertakes the only current search for terrestrial sized planets around MS-Stars. TEP was formed in 1994 to observe transits of extrasolar planets around eclipsing binaries. The current search is concentrated on CM Draconis, which is the lowest mass eclipsing binary known (dM4.5/dM4.5). It is also relatively close (17 pc), has a period of 1.26 d, and its orbital plane is nearly within our line sight (i = 89.8°). These conditions give a unique opportunity to determine the existence, or non-existence, of planets around this binary by photometric means with a high degree of certainty. Planetary orbits, if present, will be within the orbital plane of the binary components, and - due to the small size of the components - create photometrically detectable transits. The transit of a Jupitersized planet will cause a brightness drop of 8%, an Earth-sized planet one 0.08%, which is detectable with subnoise detection algorithms. The low mass and temperature of the binary components leads to the expectation that comparable planets will form much closer to the central stars than in our Solar System, and will have orbits of a few weeks to months. An observing campaign gathering several months of light curves of CM Dra will lead to a high probability of detecting a planetary transit, even when the data are taken non-continuously. The TEP network observed CM Dra from several 1-m class telescopes in since 1994, and has obtained so far about 500 h of coverage with 16000 CCD images. This paper presents the data from the first observing campaign in 1994, covering about 180 h of observations with 3900 measurements.