A Hybrid Scenario for the Formation of Brown Dwarfs and Very Low Mass Stars
- Autor(en)
- Shantanu Basu, Eduard Vorobyov
- Abstrakt
We present a calculation of protostellar disk formation and evolution in which gaseous clumps (essentially, the first Larson cores formed via disk fragmentation) are ejected from the disk during the early stage of evolution. This is a universal process related to the phenomenon of ejectionin multiple systems of point masses. However, it occurs in our model entirely due to the interaction of compact, gravitationally-bound gaseous clumps and is free from the smoothing-length uncertainty that is characteristic of models using sink particles. Clumps that survive ejection span a mass range of 0.08--0.35 Msun, and have ejection velocities 0.8 \pm 0.35 km/s, which are several times greater than the escape speed. We suggest that, upon contraction, these clumps can form substellar or low-mass stellar objects with notable disks, or even close-separation very-low-mass binaries. In this hybrid scenario, allowing for ejection of clumps rather than finished protostars/ protobrown dwarfs, disk formation and the low velocity dispersion of low-mass objects are naturally explained, while it is also consistent with the observation of isolated low-mass clumps that are ejection products. We conclude that clump ejection and the formation of isolated low mass stellar and substellar objects is a common occurrence, with important implications for understanding the initial mass function, the brown dwarf desert, and the formation of stars in all environments and epochs.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- University of Western Ontario
- Journal
- The Astrophysical Journal: an international review of astronomy and astronomical physics
- Band
- 750
- ISSN
- 0004-637X
- DOI
- https://doi.org/10.1088/0004-637X/750/1/30
- Publikationsdatum
- 2012
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103004 Astrophysik
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/3bee6f69-3980-4f52-80d6-155dedd1cc53