TRIGONOMETRIC PARALLAX OF W51 MAIN/SOUTH
- Department of Astronomy, Graduate School of Science, University of Tokyo, Tokyo 113 0033 (Japan)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany)
We report measurement of the trigonometric parallax of W51 Main/South using the Very Long Baseline Array. We measure a value of 0.185 {+-} 0.010 mas corresponding to a distance of 5.41{sup +0.31}{sub -0.28} kpc. W51 Main/South is a well-known massive star-forming region near the tangent point of the Sagittarius spiral arm of the Milky Way. Our distance to W51 yields an estimate of the distance to the Galactic center of R{sub 0} = 8.3 {+-} 0.46 (statistical) {+-}1.0 (systematic) kpc by simple geometry. Combining the parallax and proper motion measurements for W51, we obtained the full-space motion of this massive star-forming region. We find W51 is in a nearly circular orbit about the Galactic center. The H{sub 2}O masers used for our parallax measurements trace four powerful bipolar outflows within a 0.4 pc size region, some of which are associated with dusty molecular hot cores and/or hyper- or ultra-compact H II regions.
- OSTI ID:
- 21460065
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 720; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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