NOAO > Observing Info > Approved Programs > 2009A-0223
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NOAO > Observing Info > Approved Programs > 2009A-0223 |
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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: Stellar kinematics of Galactic disk: Short-period Mira stars
Abstract:
Kinematical properties of stars in Galactic disk provide important
information on its dynamical evolution and gravitational field.
Previous studies of nearby stars showed the existence of some comoving
groups as well as that of dynamically relaxed velocity distribution.
However, the formation process of the moving groups is still less well
understood because of no limits on the outer Lindblad resonance (OLR).
Short-period Mira variable (SP-Miras) stars are good tracers for
determination of kinematical properties because they are a very luminous
and relatively old population and their periods are good distance
indicators. We estimated full velocities of 58 SP-Miras at
Galactocentric distance of 6-8 kpc and suggested from the systematic-
velocities that the OLR appears to be located within 6 kpc from Galactic
center. To set stronger limits on the OLR by the sample within 6 kpc,
we propose to measure the radial velocities for 33 SP-Miras with no
radial velocities at Galactocentric distance of 5-6 kpc and estimate the
systematic velocity from their full space motions.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2009A-0223 |
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