Velocity-resolved hot water emission detected toward HL Tau with the Submillimeter Array

Abstract

Using the Submillimeter Array (SMA) on Mauna Kea, the H2-16O 10_2,9-9_3,6 transition (E_up=1863K) at 321.2 GHz has been detected toward the embedded low-mass protostar HL Tau. The line centroid is blue-shifted by 15 km/s with respect to the source velocity, and it has a FWHM of 20 km/s. The emission is tentatively resolved and extends ~3-4" over the sky (~2 beams), or ~500 AU at the distance of Taurus. The velocity offset, and to a lesser degree the spatial extent of the emission, shows that the line originates in the protostellar jet or wind. This result suggests that at least some water emission observed toward embedded sources, and perhaps also disk sources, with Herschel and Spitzer contains a wind or jet component, which is crucial for interpreting these data. These pathfinder observations done with the SMA opens a new window to studying the origin of water emission with e.g. ALMA, thus providing new insights into where water is in protostellar systems.

Accepted for publication in ApJL

References in corpus (4)

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Cited by in corpus (6)

• Candidate Water Vapor Lines to Locate the H${}_2$O Snowline through High-Dispersion Spectroscopic Observations II. The Case of a Herbig Ae Star
• Origin of warm and hot gas emission from low-mass protostars: Herschel-HIFI observations of CO J=16-15. I. Line profiles, physical conditions, and H2O abundance
• Candidate Water Vapor Lines to Locate the ${\mathrm{H}}_2\mathrm{O}$ Snowline through High-dispersion Spectroscopic Observations. III. Submillimeter ${\mathrm{H}}_2$${}^{16}\mathrm{O}$ and ${\mathrm{H}}_2$${}^{18}\mathrm{O}$ Lines
• Resolved ALMA observations of water in the inner astronomical units of the HL Tau disk
• Hot and dense water in the inner 25 AU of SVS13-A
• Zooming into the water snowline: high resolution water observations of the HL Tau disk