ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Detection of a Dense SiO Jet in the Evolved Protostellar Phase

Somnath Dutta, Chin Fei Lee, Doug Johnstone, Tie Liu, Naomi Hirano, Sheng Yuan Liu, Jeong Eun Lee, Hsien Shang, Ken'Ichi Tatematsu, Kee Tae Kim, Dipen Sahu, Patricio Sanhueza, James Di Francesco, Kai Syun Jhan, Chang Won Lee, Woojin Kwon, Shanghuo Li, Leonardo Bronfman, Hong Li Liu, Alessio TraficanteYi Jehng Kuan, Shih Ying Hsu, Anthony Moraghan, Chun Fan Liu, David Eden, Archana Soam, Qiuyi Luo

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Jets and outflows trace the accretion history of protostars. High-velocity molecular jets have been observed from several protostars in the early Class 0 phase of star formation, detected with the high-density tracer SiO. Until now, no clear jet has been detected with SiO emission from isolated evolved Class I protostellar systems. We report a prominent dense SiO jet from a Class I source G205S3 (HOPS-315: T bol ∼ 180 K, spectral index ∼0.417), with a moderately high mass-loss rate (∼0.59 ? 10-6 M o˙ yr-1) estimated from CO emission. Together, these features suggest that G205S3 is still in a high-accretion phase, similar to that expected of Class 0 objects. We compare G205S3 to a representative Class 0 system G206W2 (HOPS-399) and literature Class 0/I sources to explore the possible explanations behind the SiO emission seen at the later phase. We estimate a high inclination angle (∼40?) for G205S3 from CO emission, which may expose the infrared emission from the central core and mislead the spectral classification. However, the compact 1.3 mm continuum, C18O emission, location in the bolometric luminosity to submillimeter fluxes diagram, outflow force (∼3.26 ? 10-5 M o˙ km s-1 yr-1) are also analogous to that of Class I systems. We thus consider G205S3 to be at the very early phase of Class I, and in the late phase of high accretion. The episodic ejection could be due to the presence of an unknown binary, a planetary companion, or dense clumps, where the required mass for such high accretion could be supplied by a massive circumbinary disk.

Original languageEnglish
Article number11
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 2022 Jan 20

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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