"Extrarasolar planetary systems: regularities are found out"
Leonid Ksanfomaliti (IKI)
Abstract:
The discovery in 1995 of the first extrasolar giant planet (51 Peg b) initiated the physics of extrasolar planetary systems. By October 2005, the total number of the detected planets orbiting other stars was 168, including 49 hot jupiters, which have a semimajor axis of the orbit of less than 0.15 AU. Due to the high activity of researchers who work with the radial-velocity method, the probable candidates, say, in the 75-parsec radius, are quickly exhausted. The OGLE-type objects, even if their number increases, may only slightly contribute to the physics of extrasolar planets (or exoplanets), because even to determine the type of the companion (a giant planet, brown dwarf, or star of small mass) is extremely problematic for such weak objects. A search for Earthlike planets is still far beyond the technical capabilities: the Keplerian velocity of the Sun induced by the Earth is only 0.09 m/s, which requires to improve the results obtained by a factor of 20…30. Particularly important results were obtained in the observations of transits of the object HD 209458b, which up to 2005 summer remained the only object of this type namely due to transits. The experimental data obtained in transit observations of the extrasolar planet HD 209458b and their comparison with theoretical inferences have led to the conclusions that HD 209458b (and other similar hot jupiters) is of a (mainly) hydrogen nature and that these objects probably possess strong magnetic fields. The important role of the star metallicity in the formation of planetary systems predicted during the first years after the discovery of exoplanets has gained recognition and been developed successfully. Metallicity has become an indicator of the possible presence of planetary systems and, probably, even determines the type of planets.