2016A&A...585A.103S


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.02CEST14:50:46

2016A&A...585A.103S - Astronomy and Astrophysics, volume 585A, 103-103 (2016/1-1)

Linking low- to high-mass young stellar objects with Herschel-HIFI observations of water.

SAN JOSE-GARCIA I., MOTTRAM J.C., VAN DISHOECK E.F., KRISTENSEN L.E., VAN DER TAK F.F.S., BRAINE J., HERPIN F., JOHNSTONE D., VAN KEMPEN T.A. and WYROWSKI F.

Abstract (from CDS):

Water probes the dynamics in young stellar objects (YSOs) effectively, especially shocks in molecular outflows. It is therefore a key molecule for exploring whether the physical properties of low-mass protostars can be extrapolated to massive YSOs, an important step in understanding the fundamental mechanisms regulating star formation. As part of the WISH key programme, we investigate excited water line properties as a function of source luminosity, in particular the dynamics and the excitation conditions of shocks along the outflow cavity wall. Velocity-resolved Herschel-HIFI spectra of the H2O 202-111 (988GHz), 211-202 (752GHz) and 312-303 (1097GHz) lines were analysed, together with 12CO J=10-9and 16-15, for 52 YSOs with bolometric luminosities ranging from <1 to >105L. The H2O and 12CO line profiles were decomposed into multiple Gaussian components which are related to the different physical structures of the protostellar system. The non-LTE radiative transfer code radex was used to constrain the excitation conditions of the shocks along the outflow cavity. The profiles of the three excited water lines are similar, indicating that they probe the same gas. Two main emission components are seen in all YSOs: a broad component associated with non-dissociative shocks in the outflow cavity wall (``cavity shocks'') and a narrow component associated with the quiescent envelope material. More than 60% of the total integrated intensity in the excited water lines comes from the broad cavity shock component, while the remaining emission comes mostly from the envelope for low-mass Class I, intermediate- and high-mass objects, and dissociative ``spot shocks'' for low-mass Class 0 protostars. The widths of the water lines are surprisingly similar from low- to high-mass YSOs, whereas 12CO J=10-9 line widths increase slightly with Lbol. The excitation analysis of the cavity shock component shows stronger 752GHz emission for high-mass YSOs, most likely due to pumping by an infrared radiation field. Finally, a strong correlation with slope unity is measured between the logarithms of the total H2O line luminosity, LH2O, and Lbol, which can be extrapolated to extragalactic sources. This linear correlation, also found for CO, implies that both species primarily trace dense gas directly related to star formation activity. The water emission probed by spectrally unresolved data is largely due to shocks. Broad water and high-J CO lines originate in shocks in the outflow cavity walls for both low- and high-mass YSOs, whereas lower-J CO transitions mostly trace entrained outflow gas. The higher UV field and turbulent motions in high-mass objects compared to their low-mass counterparts may explain the slightly different kinematical properties of 12CO J=10-9and H2O lines from low- to high-mass YSOs.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: protostars - ISM: molecules - ISM: kinematics and dynamics - line: profiles

Simbad objects: 37

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Number of rows : 37

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 GAL 133.71+01.22 HII 02 25 38.1 +62 05 52           ~ 74 0
2 NAME W3 IRS 5 Y*O 02 25 40.54 +62 05 51.4           B1 329 0
3 NAME LDN 1448-mm Y*O 03 25 38.83 +30 44 06.2           ~ 301 0
4 RAFGL 490 Y*O 03 27 38.7928323987 +58 47 00.017662871           ~ 339 0
5 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 390 3
6 NGC 1333 OpC 03 29 11 +31 18.6           ~ 1218 1
7 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 553 0
8 V* V2457 Ori Or* 05 35 26.97000 -05 09 54.4644         18.858 ~ 112 0
9 IRAS 05358+3543 mul 05 39 10.4 +35 45 19           ~ 134 1
10 [SMZ2000] L1643-S3 MMS 1 smm 05 39 55.9 -07 30 28           ~ 13 0
11 NGC 2071 RNe 05 47 10 +00 18.0           ~ 609 1
12 NAME Vela XYZ Rad 08 34.0 -45 50           ~ 1110 2
13 IRAS 08448-4343 cor 08 46 33.8 -43 54 33           ~ 57 1
14 IRAS 08470-4321 cor 08 48 48.2 -43 32 25           ~ 42 0
15 BHR 71 MoC 12 01 36.810 -65 08 49.22           ~ 118 0
16 GAL 327.30-00.60 HII 15 53 05.0 -54 35 24           ~ 122 0
17 GSS 30 Y*O 16 26 21.38160 -24 23 04.0524           ~ 200 1
18 Elia 2-29 Y*O 16 27 09.43032 -24 37 18.7716           ~ 267 1
19 IRAS 16272-4837 HII 16 30 59.2 -48 43 48           ~ 21 0
20 NAME NGC 6334-I Cl* 17 20 53.35 -35 47 01.5           ~ 269 0
21 GAL 005.88-00.41 HII 18 00 30.388 -24 04 00.20           ~ 296 0
22 GAL 010.47+00.03 HII 18 08 38.4 -19 51 52           ~ 109 0
23 GRS G012.89 +00.49 HII 18 11 51.3 -17 31 29           ~ 144 0
24 W 33a Y*O 18 14 39.0 -17 52 03           ~ 584 0
25 IRAS 18151-1208 Y*O 18 17 58.114 -12 07 24.84           ~ 100 0
26 NAME SH 2-68 FIR 1 cor 18 29 49.63 +01 15 21.9           ~ 236 2
27 GAL 029.96-00.02 Y*O 18 46 03.7 -02 39 21           ~ 331 1
28 IRAS 18449-0115 cor 18 47 34.4947 -01 12 40.269           ~ 311 0
29 [MSL2003] W43-MM1 cor 18 47 47.0 -01 54 28           ~ 95 0
30 OH 34.26 +0.15 SFR 18 53 18.54 +01 14 57.9           ~ 460 0
31 W 51e1 Rad 19 23 43.77 +14 30 25.9           ~ 115 0
32 RAFGL 2591 Y*O 20 29 25.03656 +40 11 20.3316           ~ 570 0
33 [MBS2007c] CygX-N44 Rad 20 39 01.01 +42 22 50.2           ~ 362 0
34 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 483 0
35 NGC 7129 OpC 21 42 56 +66 06.2     11.5     ~ 233 0
36 NAME NGC 7129 FIR 2 IR 21 44 01.5 +66 03 40           ~ 84 0
37 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 367 3

    Equat.    Gal    SGal    Ecl

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2020.07.02-14:50:46

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