| Autor: |
TOBIN, JOHN J., STUTZ, AMELIA M., MEGEATH, S. THOMAS, FISCHER, WILLIAM J., HENNING, THOMAS, RAGAN, SARAH E., ALI, BABAR, STANKE, THOMAS, MANOJ, P., CALVET, NURIA, HARTMANN, LEE |
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| Zdroj: |
Astrophysical Journal; 1/10/2015, Vol. 798 Issue 2, p1-17, 17p |
| Abstrakt: |
We present CARMA 2.9 mm dust continuum emission observations of a sample of 14 Herschel-detected Class 0 protostars in the Orion A and B molecular clouds, drawn from the PACS Bright Red Sources (PBRS) sample (Stutz et al.). These objects are characterized by very red 24-70µm colors and prominent submillimeter emission, suggesting that they are very young Class 0 protostars embedded in dense envelopes. We detect all of the PBRS in 2.9 mm continuum emission and emission from 4 protostars and 1 starless core in the fields toward the PBRS; we also report 1 new PBRS source. The ratio of 2.9 mm luminosity to bolometric luminosity is higher by a factor of ~5 on average, compared to other well-studied protostars in the Perseus and Ophiuchus clouds. The 2.9 mm visibility amplitudes for 6 of the 14 PBRS are very flat as a function of uv-distance, with more than 50% of the source emission arising from radii < 1500 AU. These flat visibility amplitudes are most consistent with spherically symmetric envelope density profiles with ρ ∝ R-2.5. Alternatively, there could be a massive unresolved structure like a disk or a high-density inner envelope departing from a smooth power-law. The large amount of mass on scales < 1500 AU (implying high average central densities) leads us to suggest that that the PBRS with flat visibility amplitude profiles are the youngest PBRS and may be undergoing a brief phase of high mass infall/accretion and are possibly among the youngest Class 0 protostars. The PBRS with more rapidly declining visibility amplitudes still have large envelope masses, but could be slightly more evolved. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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