ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Evidence for a Molecular Jet Launched at an Unprecedented Early Phase of Protostellar Evolution

Protostellar outflows and jets play a vital role in star formation as they carry away excess angular momentum from the inner disk surface, allowing the material to be transferred toward the central protostar. Theoretically, low-velocity and poorly collimated outflows appear from the beginning of the...

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Detalles Bibliográficos
Autores: Dutta, Somnath, Lee, Chin-Fei, Hirano, Naomi, Liu, Tie, Johnstone, Doug, Liu, Sheng-Yuan, Tatematsu, Ken'ichi, Goldsmith, Paul F., Sahu, Dipen, Evans, Neal D., Sanhueza, Patricio, Kwon, Woojin, Qin, Sheng-Li, Ranjan Samal, Manash, Zhang, Qizhou, Kim, Kee-Tae, Shang, Hsien, Lee, Chang Won, Moraghan, Anthony, Jhan, Kai-Syun, Li, Shanghuo, Lee, Jeong-Eun, Traficante, A., Juvela, Mika, Bronfman, L., Eden, David J., Soam, Archana, He, Jinhua, Liu, Hong-li, Kuan, Yi-Jehng, Pelkonen, Veli Matti, Luo, Qiu-Yi, Yi, Hee-Weon, Hsu, Shih-Ying
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/279552
Acceso en línea:http://hdl.handle.net/10261/279552
Access Level:acceso abierto
Palabra clave:Star formation
Low mass stars
Stellar jets
Stellar winds
Protostars
Astrochemistry
Stellar mass loss
Stellar evolution
Young stellar objects
Early stellar evolution
Descripción
Sumario:Protostellar outflows and jets play a vital role in star formation as they carry away excess angular momentum from the inner disk surface, allowing the material to be transferred toward the central protostar. Theoretically, low-velocity and poorly collimated outflows appear from the beginning of the collapse at the first hydrostatic core (FHSC) stage. With growing protostellar core mass, high-density jets are launched, entraining an outflow from the infalling envelope. Until now, molecular jets have been observed at high velocity (≳100 km s) in early Class 0 protostars. We, for the first time, detect a dense molecular jet in SiO emission with low velocity (∼4.2 km s, deprojected ∼24 km s) from source G208.89-20.04Walma (hereafter G208Walma) using ALMA Band 6 observations. This object has some characteristics of FHSCs, such as a small outflow/jet velocity, extended 1.3 mm continuum emission, and N D line emission. Additional characteristics, however, are typical of early protostars: collimated outflow and SiO jet. The full extent of the outflow corresponds to a dynamical timescale of ∼ 930 − 100 + 200 yr. The spectral energy distribution also suggests a very young source having an upper limit of T ∼ 31 K and L ∼ 0.8 L . We conclude that G208Walma is likely in the transition phase from FHSC to protostar, and the molecular jet has been launched within a few hundred years of initial collapse. Therefore, G208Walma may be the earliest object discovered in the protostellar phase with a molecular jet.

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