2014A&A...572A..81S


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.29CET15:08:15

2014A&A...572A..81S - Astronomy and Astrophysics, volume 572A, 81-81 (2014/12-1)

Water in low-mass star-forming regions with Herschel. The link between water gas and ice in protostellar envelopes.

SCHMALZL M., VISSER R., WALSH C., ALBERTSSON T., VAN DISHOECK E.F., KRISTENSEN L.E. and MOTTRAM J.C.

Abstract (from CDS):

Our aim is to determine the critical parameters in water chemistry and the contribution of water to the oxygen budget by observing and modelling water gas and ice for a sample of eleven low-mass protostars, for which both forms of water have been observed. A simplified chemistry network, which is benchmarked against more sophisticated chemical networks, is developed that includes the necessary ingredients to determine the water vapour and ice abundance profiles in the cold, outer envelope in which the temperature increases towards the protostar. Comparing the results from this chemical network to observations of water emission lines and previously published water ice column densities, allows us to probe the influence of various agents (e.g., far-ultraviolet (FUV) field, initial abundances, timescales, and kinematics). The observed water ice abundances with respect to hydrogen nuclei in our sample are 30-80ppm, and therefore contain only 10-30% of the volatile oxygen budget of 320ppm. The keys to reproduce this result are a low initial water ice abundance after the pre-collapse phase together with the fact that atomic oxygen cannot freeze-out and form water ice in regions with Tdust>15K. This requires short prestellar core lifetimes ≲0.1Myr. The water vapour profile is shaped through the interplay of FUV photodesorption, photodissociation, and freeze-out. The water vapour line profiles are an invaluable tracer for the FUV photon flux and envelope kinematics. The finding that only a fraction of the oxygen budget is locked in water ice can be explained either by a short pre-collapse time of ≲0.1Myr at densities of nH∼104cm–3, or by some other process that resets the initial water ice abundance for the post-collapse phase. A key for the understanding of the water ice abundance is the binding energy of atomic oxygen on ice.

Abstract Copyright:

Journal keyword(s): ISM: abundances - ISM: kinematics and dynamics - ISM: molecules - stars: formation

Simbad objects: 17

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Number of rows : 17

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 575 1
2 [JCC87] IRAS 4 FIR 03 29 10.9 +31 13 26           ~ 462 0
3 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 547 0
4 LDN 1489 DNe 04 04 47.5 +26 19 42           ~ 190 0
5 HBC 393 FU* 04 31 34.077 +18 08 04.90           K3V/M3III 777 2
6 IRAS 04361+2547 Y*O 04 39 13.898 +25 53 20.63           ~ 183 1
7 IRAS 04365+2535 Y*O 04 39 35.194 +25 41 44.73           ~ 228 0
8 LDN 1527 DNe 04 39 53 +25 45.0           ~ 477 0
9 NAME Taurus Dark Cloud SFR 04 41.0 +25 52           ~ 3361 0
10 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1334 0
11 2MASS J08254384-5100326 Y*O 08 25 43.85 -51 00 32.7           ~ 295 1
12 IRAS 15398-3359 Y*? 15 43 02.21016 -34 09 07.7112       18.38 21.72 ~ 127 0
13 GSS 30 Y*O 16 26 21.38160 -24 23 04.0524           ~ 197 1
14 HBC 650 TT* 16 34 29.32 -15 47 01.4           K3.0 164 2
15 2MASS J19014805-3657219 Y*O 19 01 48.056 -36 57 21.95           ~ 93 0
16 HH 100 HH 19 01 49.1 -36 58 16           ~ 79 0
17 V* V710 CrA Or* 19 01 50.67792 -36 58 09.6132           K7: 114 0

    Equat.    Gal    SGal    Ecl

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2020.01.29-15:08:15

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