TRIGONOMETRIC PARALLAXES OF MASSIVE STAR-FORMING REGIONS. IX. THE OUTER ARM IN THE FIRST QUADRANT

Journal Article · Fri Jan 20 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/745/1/82· OSTI ID:22011980

Sanna, A; Menten, K M; Brunthaler, A ^[1]; Reid, M J; Dame, T M ^[2]; Moscadelli, L ^[3]; Zheng, X W ^[4]; Xu, Y ^[5]

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1. Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze (Italy)
4. Department of Astronomy, Nanjing University, Nanjing 210093 (China)
5. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210093 (China)

We report a trigonometric parallax measurement with the Very Long Baseline Array for the water maser in the distant high-mass star-forming region G75.30+1.32. This source has a heliocentric distance of 9.25{sup +0.45}{sub -0.40} kpc, which places it in the Outer arm in the first Galactic quadrant. It lies 200 pc above the Galactic plane and is associated with a substantial H I enhancement at the border of a large molecular cloud. At a Galactocentric radius of 10.7 kpc, G75.30+1.32 is in a region of the Galaxy where the disk is significantly warped toward the North Galactic Pole. While the star-forming region has an instantaneous Galactic orbit that is nearly circular, it displays a significant motion of 18 km s{sup -1} toward the Galactic plane. The present results, when combined with two previous maser studies in the Outer arm, yield a pitch angle of about 12 Degree-Sign for a large section of the arm extending from the first quadrant to the third.

• OSTI ID: 22011980
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 745; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
GALAXIES
INCLINATION
MASERS
MASS
ORBITS
STARS
WATER