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- Title
Outer rotation curve of the Galaxy with VERA. II. Annual parallax and proper motion of the star-forming region IRAS21379+5106.
- Authors
Hiroyuki NAKANISHI; Nobuyuki SAKAI; Tomoharu KURAYAMA; Mitsuhiro MATSUO; Hiroshi IMAI; Ross A. BURNS; Takeaki OZAWA; Mareki HONMA; Katsunori M. SHIBATA; Noriyuki KAWAGUCHI
- Abstract
We conducted astrometric very long baseline interferometry (VLBI) observations ofwatervapor maser emission in the massive star-forming region IRAS 21379+5106 in order to measure the annual parallax and proper motion, using VLBI Exploration of Radio Astrometry (VERA). The annual parallax measured 0.262 ± 0.031 mas, corresponding to a distance of 3.82+0.51-0.41 kpc. The proper motion was (μα cosδ, μδ) = (-2.74 ± 0.08, -2.87 ± 0.18) mas yr-1. By using this result, the Galactic rotational velocity was estimated to be Vθ = 218 ± 19kms-1 at the galactocentric distance R = 9.22 ± 0.43 kpc, when we adopted the Galactic constants R0 = 8.05 ± 0.45 kpc and V0 = 238 ± 14km s-1. With the newly determined distance, the bolometric luminosity of the central young stellar object was reestimated to be (2.15 ± 0.54) × 103 L⊙, which corresponds to the spectral type of B2-B3. The maser features were found to be distributed along a straight line extending from the southwest to the northeast. In addition, a vector map of the internal motions, constructed from the residual proper motions, implies that the maser features trace a bipolar flow, and that it cannot be explained by simple ballistic motions.
- Subjects
ASTROMETRY; GALAXIES; KINEMATICS; PARALLAX; ASTROPHYSICS
- Publication
Publications of the Astronomical Society of Japan, 2015, Vol 67, Issue 4, p1
- ISSN
0004-6264
- Publication type
Article
- DOI
10.1093/pasj/psv012