Occurrence frequency of co outflows in massive protostellar candidates
Por:
Kim K.-T., Kurtz S.E.
Publicada:
1 ene 2006
Resumen:
We mapped 12 massive protostellar candidates in the CO J = 2-1 line, which, in combination with Zhang et al., completes an unbiased survey of outflows for all 48 sources with l > 50° in a sample of 101 massive protostellar candidates. We detected outflows in 10 sources, implying 88% occurrence frequency of outflows for the 48 sources. This supports the conclusion of previous studies that bipolar outflows are an integral component in the formation process of massive stars. The vast majority of the observed outflows are much more massive (>10 M?) and energetic (>100 M ? km s-1) than outflows from low-mass protostars. They also have large mass outflow rates (>2 × 10-4 M ? yr-1), suggesting large (?1 × 10 -4 M? yr-1) accretion rates sufficient to overcome the radiation pressure of the central massive protostars. We compared the frequency distribution of collimation factors of 40 massive out-flows including those of this study with that of 36 low-mass outflows from the literature and found no significant difference between the two. All these results are consistent with the suggestion that massive stars form through accretion as do low-mass stars but with much higher accretion rates. © 2006. The American Astronomical Society. All rights reserved.
Filiaciones:
Kim K.-T.:
Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801, United States
Korea Astronomy and Space Science Institute, 61-1 Hwaam-Dong, Yuseong-Gu, Daejeon 305-348, South Korea
Kurtz S.E.:
Centro de Radioastronomía y Astrofisica, Universidad Nacional Autónoma de México, Apartado Postal 3-72, Morelia 58089, Michoacán, Mexico
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