Herschel/HIFI spectroscopy of the intermediate mass protostar NGC 7129 FIRS 2
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Herschel/HIFI observations of water from the intermediate mass protostar
NGC 7129 FIRS 2 provide a powerful diagnostic of the physical conditions
in this star formation environment. Six spectral settings, covering four
H216O and two H218O lines,
were observed and all but one H218O line were
detected. The four H216O lines discussed here
share a similar morphology: a narrower, ˜6 km s-1,
component centered slightly redward of the systemic velocity of NGC 7129
FIRS 2 and a much broader, ˜25 km s-1 component centered
blueward and likely associated with powerful outflows. The narrower
components are consistent with emission from water arising in the
envelope around the intermediate mass protostar, and the abundance of
H2O is constrained to ˜10-7 for the outer
envelope. Additionally, the presence of a narrow self-absorption
component for the lowest energy lines is likely due to self-absorption
from colder water in the outer envelope. The broader component, where
the H2O/CO relative abundance is found to be ˜0.2, appears
to be tracing the same energetic region that produces strong CO emission
at high J.
Herschel is an ESA space observatory with science instruments provided
by European-led Principal Investigator consortia and with important
participation from NASA. Appendix (page 6) is only available in
electronic form at http://www.aanda.org
Originalsprog | Engelsk |
---|---|
Tidsskrift | Astronomy & Astrophysics |
Vol/bind | 521 |
Sider (fra-til) | L41 |
ISSN | 0004-6361 |
Status | Udgivet - 1 okt. 2010 |
ID: 35114335