Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-03-07
Astronomy and Astrophysics
Astrophysics
33 pages, 16 figures, accepted by the Astronomical Journal
Scientific paper
10.1088/0004-6256/135/6/2526
We present the Class I protostellar binary separation distribution based on the data tabulated in the companion paper. We verify the excess of Class I binary stars over solar-type main-sequence stars, especially at separations beyond 500 AU. Although our sources are in nearby star forming regions distributed across the entire sky (including Orion), none of our objects are in a high stellar density environment. The binary separation distribution changes significantly during the Class I phase, and the binary frequency at separations greater than 1000 AU declines steadily with respect to spectral index. Despite these changes, the binary frequency remains constant until the end of the Class I phase, when it drops sharply. We propose a scenario to account for the changes in the Class I binary separation distribution. This scenario postulates that companions with a separation greater than ~1000 AU were ejected during the Class 0 phase, but remain gravitationally bound due to the mass of the envelope. As the envelope dissipates, these companions become unbound and the binary frequency at wide separations declines. This scenario predicts that a large number of Class 0 objects should be non-hierarchical multiple systems, and that many Class I YSOs with a widely separated companion should also have a very close companion. We also find that Class I protostars are not dynamically pristine, and have experienced dynamical evolution before they are visible as Class I objects. For the first time, evidence is presented showing that the Class I binary frequency and the binary separation distribution strongly depend on the star forming environment. The reason for this dependence remains unclear.
Connelley Michael
Reipurth Bo
Tokunaga Alan
No associations
LandOfFree
The Evolution of the Multiplicity of Embedded Protostars II: Binary Separation Distribution & Analysis does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Evolution of the Multiplicity of Embedded Protostars II: Binary Separation Distribution & Analysis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Evolution of the Multiplicity of Embedded Protostars II: Binary Separation Distribution & Analysis will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-444967