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DISTANCE AND PROPER MOTION MEASUREMENT OF THE RED SUPERGIANT, S PERSEI, WITH VLBI H2O MASER ASTROMETRY
- Source :
- The Astrophysical Journal. 721:267-277
- Publication Year :
- 2010
- Publisher :
- American Astronomical Society, 2010.
-
Abstract
- We have conducted VLBA phase-referencing monitoring of H2O masers around the red supergiant, S Persei, for six years. We have fitted maser motions to a simple expanding-shell model with a common annual parallax and stellar proper motion, and obtained the annual parallax as 0.413+/-0.017 mas, and the stellar proper motion as (-0.49+/-0.23 mas/yr, -1.19+/-0.20 mas/yr) in right ascension and declination, respectively. The obtained annual parallax corresponds to the trigonometric distance of 2.42+0.11-0.09 kpc. Assuming the Galactocentric distance of the Sun of 8.5 kpc, the circular rotational velocity of the LSR at the distance of the Sun of 220 km/s, and a flat Galactic rotation curve, S Persei is suggested to have a non-circular motion deviating from the Galactic circular rotation for 15 km/s, which is mainly dominated by the anti rotation direction component of 12.9+/-2.9 km/s. This red supergiant is thought to belong to the OB association, Per OB1, so that this non-circular motion is representative of a motion of the OB association in the Milky Way. This non-circular motion is somewhat larger than that explained by the standard density-wave theory for a spiral galaxy, and is attributed to either a cluster shuffling of the OB association, or to non-linear interactions between non-stationary spiral arms and multi-phase interstellar media. The latter comes from a new view of a spiral arm formation in the Milky Way suggested by recent large N-body/smoothed particle hydrodynamics numerical simulations.<br />Comment: 28 pages, 11 figures, 5 tables, ApJ (accepted)
- Subjects :
- Physics
Spiral galaxy
Proper motion
Astrophysics::High Energy Astrophysical Phenomena
Milky Way
FOS: Physical sciences
Astronomy and Astrophysics
structure -- masers -- supergiants [Galaxy]
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Astrometry
Astrophysics - Astrophysics of Galaxies
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Galaxy: structure -- masers -- supergiants
Astrophysics::Solar and Stellar Astrophysics
Red supergiant
Astrophysics::Earth and Planetary Astrophysics
Right ascension
Parallax
Astrophysics::Galaxy Astrophysics
Galaxy rotation curve
Subjects
Details
- ISSN :
- 15384357 and 0004637X
- Volume :
- 721
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....8d9584bd85452fa19e5f9a5fb36309ac