| Description |
We propose a survey of water lines toward an unbiased flux limited
sample of low-mass protostars newly discovered in recent Spitzer and
Herschel Gould Belt imaging surveys. Water has long been speculated to
be a key molecule in the chemistry and physics of star-forming
regions, but its actual role is only now starting to emerge thanks to
Herschel. Initial HIFI data reveal surprisingly complex water emission
profiles, which uniquely trace the different dynamical processes
during the embedded phase of star formation (outflows, jets, shocks,
infall, expansion). By using lines originating from different energy
levels, the water abundance in the cold and warm gas can be determined
as function of velocity and thus the chemical processes that shape
them (gas-grain interactions, high temperature reactions). The
ortho/para and HDO/H2O ratios hold important clues on the temperature
history of the clouds and on the journey of water from cores to disks
and planets. Combination with PACS data on water and related species
(O, OH, CO) can determine the total gas cooling budget and can
quantify the .feedback. of the protostar on its surroundings in terms
of UV radiation and shocks.
The unbiased WILL sample allows all of these questions to be studied
as function of source characteristics and protostellar evolution in a
statistically significant way, thus charting the processes that shape
the emerging young star and disk in the critical period from the
collapse phase to the envelope dispersion stage. No other space-based
heterodyne mission will be available to provide velocity resolved
water lines for at least 30 years, making this program a true Herschel
Gould Belt line emission legacy. |
| Publication |
Outflows, infall and evolution of a sample of embedded low-mass protostars. The William Herschel Line Legacy (WILL) survey . Mottram J. C. et al. . Astronomy & Astrophysics, Volume 600, id.A99, 48 pp. . 600 . 10.1051\/0004-6361\/201628682 . 2017A&A...600A..99M ,
Herschel-PACS observations of far-IR lines in young stellar objects. I. [OI] and H2O at 63 μm . Riviere-Marichalar P. et al. . Astronomy & Astrophysics, Volume 594, id.A59, 25 pp. . 594 . 10.1051\/0004-6361\/201527829 . 2016A&A...594A..59R ,
Evolution of the atomic component in protostellar outflows . Sperling T. et al. . Astronomy and Astrophysics . null . null . 2021A&A...650A.173S ,
The Herschel-PACS Legacy of Low-mass Protostars: The Properties of Warm and Hot Gas Components and Their Origin in Far-UV Illuminated Shocks . Karska Agata et al. . The Astrophysical Journal Supplement Series, Volume 235, Issue 2, article id. 30, 45 pp. (2018). . 235 . 10.3847\/1538-4365\/aaaec5 . 2018ApJS..235...30K ,
Water in star-forming regions: physics and chemistry from clouds to disks as probed by Herschel spectroscopy . van Dishoeck E. F. et al. . Astronomy and Astrophysics . null . null . 2021A&A...648A..24V ,
|
