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The Subaru Seminar is usually held in Room 104 of the Hilo Base Facility, adjacent to the main lobby. Everyone is welcome to attend. If you are interested in giving a seminar, please contact Subaru seminar organizers (Tae-Soo Pyo, Sherry Yeh, Nagayoshi Ohashi) by email : (please change"_at" to @).

July 14, Monday, at 11:00 am

" Radial-velocity search for exoplanets around metal-rich stars "

Hiroki Harakawa


Correlation between stellar parameters and planet properties, including planet occurrence rates, can be considered as fundamental information for planet formation and evolution in various environment of planet birthplace. Thanks to increasing the number of planet samples, statistical studies become available. In particular, hundreds of Jovian-planet samples have been contributing to constrain planet formation theories taking account of evolutions of protoplanetary disks and planet orbits such as orbital migration and planet-planet scattering. However, observational and statistical study for planet distribution is still open to debate, particularly in its correlation with their host stellar metallicities. While previous studies of planet-metallicity correlation have mainly focused on integrated occurrence rate of planets over planetary mass and orbital period, it is also important to reveal dependence of mass and period distribution of planets on stellar metallicity for a deeper understanding of orbital evolution. Recent studies of circumstellar disks have suggested that stellar metallicity may have significant importance to the disk-lifetime, a key parameter of planetary migration theory. Since 2009, we have conducted a radial-velocity survey for metal-rich solar-type stars mainly using the 188-cm telescope at Okayama Astrophysical Observatory and the Subaru Telescope. This planet-search program originates from the N2K program that mainly aimed for detecting Hot-Jupiters around metal-rich solar-type stars. To date, we have discovered 5 new exoplanets around three metal-rich stars. The planet masses range between 1 MJ and 6.5MJ in the period range of 280-2300 days. In this talk, I will review the backgrounds and discuss the features of these detected planets.

Seminars are also held at JAC, CFHT, and IfA.

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