The extremely collimated bipolar H_2O jet from the NGC 1333-IRAS 4B protostar

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.

9 pages, 8 figures, A&A accepted

References in corpus (3)

• PdBI sub-arcsecond study of the SiO microjet in HH212 - Origin and collimation of Class 0 jets
• Time-Resolved AU-Scale Jets Traced by Masers in the IRAS 4A/B Regions of NGC1333
• Observations of Water Masers in the NGC 1333 IRAS 4 Region

Cited by in corpus (13)

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• The CALYPSO IRAM-PdBI survey of jets from Class 0 protostars. Are jets ubiquitous in young stars ?
• Astrometry of H${}_2$O Masers in Nearby Star-Forming Regions with VERA --- IV. L1448C
• Subarcsecond resolution observations of warm water towards three deeply embedded low-mass protostars
• Angular momentum profiles of Class 0 protostellar envelopes
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• The HDO/H2O ratio in gas in the inner regions of a low-mass protostar
• Millimeter multiplicity in DR21(OH): outflows, molecular cores and envelopes
• Internal and relative motions of the Taurus and Ophiuchus star-forming regions
• Molecule survival in magnetized protostellar disk winds. II. Predicted H2O line profiles versus Herschel/HIFI observations
• Radio Imaging of the NGC 1333 IRAS 4B Region
• PRODIGE - envelope to disk with NOEMA: VII. (Complex) organic molecules in the NGC1333 IRAS4B1 outflow: A new laboratory for shock chemistry