NOAO >   Observing Info >   Approved Programs >   2008B-0366

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Proposal Information for 2008B-0366


PI: Tsuyoshi Sakamoto, Japan Spaceguard Association, sakamoto@spaceguard.or.jp
Address: Bisei Spaceguard Center, 1716-3, Ookura, Bisei, Ibara, Okayama 714-1411, Japan

CoI: Takashi Hasegawa, Gunma Astronomical Observatory

Title: Short-period Mira variable stars diagnostics for dynamics of Galactic disk

Abstract: Mira variable stars with periods shorter than 300 days (SP-Miras) are good tracers for determination of dynamical properties of the Galactic disk from the points of the identification, age, and distance- estimate. Recent accurate astrometric data elucidated the existence of some moving groups of stars on orbits deviated from the circular orbits in the solar neighborhood. In order to examine their formation scenario, it is vital to set strong limits on the resonances of the potential of the bar and spiral arms from the full space motions of the stars because the distribution of the orbits is sensitive to the positions of the resonances. We produced a sample of 370 Galactic SP- Miras that are mainly located at the Galactocentric distance of 5-12 kpc. This sample includes 111 SP-Miras with no radial velocities. In this semester, we propose to measure the radial velocities of 38 SP- Miras with no radial velocities at the Galactocentric distance of 5-7 kpc and to limit on the positions of the resonances from their systematic motion.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2008B-0366

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