A triple protostar system formed via fragmentation of a gravitationally unstable disk
Kratter, Kaitlin M.
Persson, Magnus V.
Looney, Leslie W.
Dunham, Michael M.
Chandler, Claire J.
Sadavoy, Sarah I.
Harris, Robert J.
Pérez, Laura M.
MetadataShow full item record
PublisherNATURE PUBLISHING GROUP
CitationA triple protostar system formed via fragmentation of a gravitationally unstable disk 2016, 538 (7626):483 Nature
Rights© 2016 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
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AbstractBinary and multiple star systems are a frequent outcome of the star formation process1;2, and as a result, almost half of all sun-like stars have at least one companion star3. Theoretical studies indicate that there are two main pathways that can operate concurrently to form binary/multiple star systems: large scale fragmentation of turbulent gas cores and filaments4;5 or smaller scale fragmen- tation of a massive protostellar disk due to gravitational instability6;7. Observa- tional evidence for turbulent fragmentation on scales of >1000 AU has recently emerged8;9. Previous evidence for disk fragmentation was limited to inferences based on the separations of more-evolved pre-main sequence and protostellar multiple systems10;11;12;13. The triple protostar system L1448 IRS3B is an ideal candidate to search for evidence of disk fragmentation. L1448 IRS3B is in an early phase of the star formation process, likely less than 150,000 years in age14, and all protostars in the system are separated by <200 AU. Here we report observations of dust and molecular gas emission that reveal a disk with spiral structure surrounding the three protostars. Two protostars near the center of the disk are separated by 61 AU, and a tertiary protostar is coincident with a spiral arm in the outer disk at a 183 AU separation13. The inferred mass of the central pair of protostellar objects is ∼1 M⊙, while the disk surrounding the three protostars has a total mass of ∼0.30 M⊙. The tertiary protostar itself has a minimum mass of ∼0.085 M⊙. We demonstrate that the disk around L1448 ppears susceptible to disk fragmentation at radii between 150 AU and 320 AU, overlapping with the location of the tertiary protostar. This is consis- tent with models for a protostellar disk that has recently undergone gravitational instability, spawning one or two companion stars.
NotePublished online 26 October 2016; 6 month embargo.
VersionFinal accepted manuscript
SponsorsK.M.K. is supported in part by the National Science Foundation under Grant No. AST-1410174