Protostellar Outflows Shed Light on the Dominant Close Companion Star Formation Pathways
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| Autores principales: | , , , , , , , , , , , , , |
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| Formato: | Preprint |
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2026
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| _version_ | 1866908859240546304 |
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| author | Sponzilli, Ryan Looney, Leslie Tobin, John J. Encalada, Frankie J. Fourkas, Austen Arce, Hector Cox, Erin Di Francesco, James Karnath, Nicole Li, Zhi-Yun Murillo, Nadia Offner, Stella Sadavoy, Sarah Sharma, Rajeeb |
| author_facet | Sponzilli, Ryan Looney, Leslie Tobin, John J. Encalada, Frankie J. Fourkas, Austen Arce, Hector Cox, Erin Di Francesco, James Karnath, Nicole Li, Zhi-Yun Murillo, Nadia Offner, Stella Sadavoy, Sarah Sharma, Rajeeb |
| contents | Understanding the formation pathway for close-companion protostars is central to unraveling the processes that govern stellar multiplicity and very early star formation. We analyze a large sample of 51 Class 0/I close-companion protostellar systems, of which 38 show detectable outflows, yielding 42 measured outflows used in our analysis. We use ALMA observations of 11 systems in Perseus and 40 systems in Orion. These companions formed either directly at these small scales ($\lesssim 500$ au separations) via disk fragmentation or at larger scales ($> 1000$ au separations) via turbulent fragmentation followed by inward migration. Because of differences in formation mechanism, the former is expected to have preferentially aligned disks and outflows, whereas the latter is expected to show no preferred alignment. The relative prevalence of these formation pathways remains uncertain, yet it is critical to forming a comprehensive picture of star formation. We examine the distribution of position angles of companion protostars relative to the position angles of their molecular outflows. The outflow, as traced by $^{12}$CO ($J=2\rightarrow1$), is a useful proxy for the angular momentum of the system, expected to be orthogonal to the binary orbital plane. We use a simple model to account for random sampling of inclination and orbital phase in each system, finding that the observations are consistent with a distribution in which the outflows are preferentially orthogonal to the companions. Based on this analysis, we suggest disk fragmentation is the dominant formation pathway for close-companion protostellar systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_01347 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Protostellar Outflows Shed Light on the Dominant Close Companion Star Formation Pathways Sponzilli, Ryan Looney, Leslie Tobin, John J. Encalada, Frankie J. Fourkas, Austen Arce, Hector Cox, Erin Di Francesco, James Karnath, Nicole Li, Zhi-Yun Murillo, Nadia Offner, Stella Sadavoy, Sarah Sharma, Rajeeb Solar and Stellar Astrophysics Astrophysics of Galaxies Understanding the formation pathway for close-companion protostars is central to unraveling the processes that govern stellar multiplicity and very early star formation. We analyze a large sample of 51 Class 0/I close-companion protostellar systems, of which 38 show detectable outflows, yielding 42 measured outflows used in our analysis. We use ALMA observations of 11 systems in Perseus and 40 systems in Orion. These companions formed either directly at these small scales ($\lesssim 500$ au separations) via disk fragmentation or at larger scales ($> 1000$ au separations) via turbulent fragmentation followed by inward migration. Because of differences in formation mechanism, the former is expected to have preferentially aligned disks and outflows, whereas the latter is expected to show no preferred alignment. The relative prevalence of these formation pathways remains uncertain, yet it is critical to forming a comprehensive picture of star formation. We examine the distribution of position angles of companion protostars relative to the position angles of their molecular outflows. The outflow, as traced by $^{12}$CO ($J=2\rightarrow1$), is a useful proxy for the angular momentum of the system, expected to be orthogonal to the binary orbital plane. We use a simple model to account for random sampling of inclination and orbital phase in each system, finding that the observations are consistent with a distribution in which the outflows are preferentially orthogonal to the companions. Based on this analysis, we suggest disk fragmentation is the dominant formation pathway for close-companion protostellar systems. |
| title | Protostellar Outflows Shed Light on the Dominant Close Companion Star Formation Pathways |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2603.01347 |