2014A&A...572A..21M


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.13CEST07:43:15

2014A&A...572A..21M - Astronomy and Astrophysics, volume 572A, 21-21 (2014/12-1)

Water in star-forming regions with Herschel (WISH). V. The physical conditions in low-mass protostellar outflows revealed by multi-transition water observations.

MOTTRAM J.C., KRISTENSEN L.E., VAN DISHOECK E.F., BRUDERER S., SAN JOSE-GARCIA I., KARSKA A., VISSER R., SANTANGELO G., BENZ A.O., BERGIN E.A., CASELLI P., HERPIN F., HOGERHEIJDE M.R., JOHNSTONE D., VAN KEMPEN T.A., LISEAU R., NISINI B., TAFALLA M., VAN DER TAK F.F.S. and WYROWSKI F.

Abstract (from CDS):

Outflows are an important part of the star formation process as both the result of ongoing active accretion and one of the main sources of mechanical feedback on small scales. Water is the ideal tracer of these effects because it is present in high abundance for the conditions expected in various parts of the protostar, particularly the outflow. We constrain and quantify the physical conditions probed by water in the outflow-jet system for Class 0 and I sources. We present velocity-resolved Herschel HIFI spectra of multiple water-transitions observed towards 29 nearby Class 0/I protostars as part of the WISH guaranteed time key programme. The lines are decomposed into different Gaussian components, with each component related to one of three parts of the protostellar system; quiescent envelope, cavity shock and spot shocks in the jet and at the base of the outflow. We then use non-LTE radex models to constrain the excitation conditions present in the two outflow-related components. Water emission at the source position is optically thick but effectively thin, with line ratios that do not vary with velocity, in contrast to CO. The physical conditions of the cavity and spot shocks are similar, with post-shock H2 densities of order 105-108cm–3 and H2O column densities of order 1016-1018cm–2. H2O emission originates in compact emitting regions: for the spot shocks these correspond to point sources with radii of order 10-200 AU, while for the cavity shocks these come from a thin layer along the outflow cavity wall with thickness of order 1-30 AU. Water emission at the source position traces two distinct kinematic components in the outflow; J shocks at the base of the outflow or in the jet, and C shocks in a thin layer in the cavity wall. The similarity of the physical conditions is in contrast to off-source determinations which show similar densities but lower column densities and larger filling factors. We propose that this is due to the differences in shock properties and geometry between these positions. Class I sources have similar excitation conditions to Class 0 sources, but generally smaller line-widths and emitting region sizes. We suggest that it is the velocity of the wind driving the outflow, rather than the decrease in envelope density or mass, that is the cause of the decrease in H2O intensity between Class 0 and I sources.

Abstract Copyright:

Journal keyword(s): stars: formation - ISM: jets and outflows - ISM: molecules - stars: protostars

VizieR on-line data: <Available at CDS (J/A+A/572/A21): table1.dat sp/*>

Errata: + corrigendum vol. 574, p. C3 (2015)

Simbad objects: 44

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Number of rows : 44

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 NAME the Cold Spot ? 03 13 -20.5           ~ 45 0
2 LDN 1448 DNe 03 22.5 +30 35           ~ 466 0
3 [BCM90] B1 ? 03 25 37 +30 45.5           ~ 8 0
4 NAME LDN 1448-mm Y*O 03 25 38.83 +30 44 06.2           ~ 301 0
5 [BCM90] R2 ? 03 25 40 +30 43.5           ~ 8 0
6 [CMG2014] MM3 mm 03 28 55.500 +31 14 34.75           ~ 8 0
7 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 390 3
8 NAME HH 7-11 FIR 03 29 03.9 +31 16 06           ~ 332 0
9 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 596 1
10 [JCC87] IRAS 4 FIR 03 29 10.9 +31 13 26           ~ 465 0
11 NGC 1333 OpC 03 29 11 +31 18.6           ~ 1219 1
12 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 553 0
13 LDN 1489 DNe 04 04 47.5 +26 19 42           ~ 195 0
14 LDN 1551 DNe 04 31 30.0 +18 12 30           ~ 768 1
15 RAFGL 5123 FU* 04 31 34.07736 +18 08 04.9020           K3V/M3III 811 0
16 IRAS 04361+2547 Y*O 04 39 13.89767 +25 53 20.6340           ~ 185 1
17 IRAS 04365+2535 Y*O 04 39 35.19360 +25 41 44.7252           ~ 237 0
18 LDN 1527 DNe 04 39 53 +25 45.0           ~ 495 0
19 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1359 0
20 2MASS J08254384-5100326 Y*O 08 25 43.85 -51 00 32.7           ~ 298 1
21 Ass Cha T 2-21 TT* 11 06 15.3485848381 -77 21 56.737939872   12.58 11.01   9.35 G5Ve 123 0
22 IRAS 11051-7706 Y*O 11 06 46.025 -77 22 29.67           ~ 71 0
23 BHR 71 MoC 12 01 36.810 -65 08 49.22           ~ 119 0
24 V* DK Cha Or* 12 53 17.2028372976 -77 07 10.727661977           F0 132 0
25 IRAS 15398-3359 Y*? 15 43 02.21016 -34 09 07.7112       18.38 21.72 ~ 128 0
26 GSS 30 Y*O 16 26 21.38160 -24 23 04.0524           ~ 200 1
27 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 373 0
28 Elia 2-29 Y*O 16 27 09.43032 -24 37 18.7716           ~ 267 1
29 IRAS 16285-2355 Y*O 16 31 35.65752 -24 01 29.4708           ~ 103 0
30 HBC 650 TT* 16 34 29.32 -15 47 01.4           K3.0 165 2
31 LDN 483 DNe 18 17 35 -04 39.8           ~ 209 0
32 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 912 2
33 NAME SH 2-68 FIR 1 cor 18 29 49.63 +01 15 21.9           ~ 236 2
34 NAME Serpens SMM 4 cor 18 29 57.1 +01 13 15           ~ 123 0
35 NAME SERPENS SMM 3 smm 18 29 59.7 +01 14 00           ~ 84 1
36 CHLT 3 * 19 01 48.10 -36 57 22.7           K6V 29 0
37 HH 100 HH 19 01 49.1 -36 58 16           ~ 79 0
38 V* V710 CrA Or* 19 01 50.67792 -36 58 09.6132           K7: 117 0
39 LDN 723 DNe 19 18 12 +19 13.6           ~ 153 0
40 LDN 663 DNe 19 36 55 +07 34.4           ~ 555 0
41 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 484 0
42 [DE95] LDN 1157 B2 out 20 39 09.3 +68 00 44           ~ 59 0
43 [DE95] LDN 1157 B1 out 20 39 11 +68 01.3           ~ 180 0
44 [BCM90] R1 ? ~ ~           ~ 8 0

    Equat.    Gal    SGal    Ecl

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2020.07.13-07:43:15

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