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The extremely collimated bipolar H_2O jet from the NGC 1333-IRAS 4B protostar
- Publication Year :
- 2009
- Publisher :
- arXiv, 2009.
-
Abstract
- We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding medium. The main aim is to measure the absolute positions and proper motions of the H_2O spots in order to investigate the kinematics of the region from where the jet is launched. We imaged the protostars in the nearby region NGC 1333-IRAS 4 in the water maser line at 22.2 GHz by using the VLBA in phase-reference mode at the milliarcsecond scale over four epochs, spaced by one month to measure proper motions. Two protostars (A2 and B) were detected in a highly variable H_2O maser emission, with an active phase shorter than four weeks. The H_2O maps allow us to trace the fast jet driven by the B protostar: we observed both the red- and blue-shifted lobes very close to the protostar, =< 35 AU, moving away with projected velocities of ~10-50 km/s. The comparison with the molecular outflow observed at larger scale suggests a jet precession with a 18'/yr rate. By measuring the positional spread of the H_2O spots we estimate a jet width of ~2 AU at a distance of ~12 AU from the driving protostar.<br />9 pages, 8 figures, A&A accepted
- Subjects :
- Physics
Jet (fluid)
Proper motion
Star formation
Astrophysics::High Energy Astrophysical Phenomena
FOS: Physical sciences
Astronomy and Astrophysics
Context (language use)
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics - Astrophysics of Galaxies
law.invention
Free molecular flow
Space and Planetary Science
law
Astrophysics of Galaxies (astro-ph.GA)
Protostar
Astrophysics::Solar and Stellar Astrophysics
Maser
Astrophysics::Galaxy Astrophysics
Line (formation)
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....91481bafe7e1950300faeeba05dc4845
- Full Text :
- https://doi.org/10.48550/arxiv.0903.2770