2009A&A...507.1425V


Query : 2009A&A...507.1425V

2009A&A...507.1425V - Astronomy and Astrophysics, volume 507, 1425-1442 (2009/12-1)

APEX-CHAMP+ high-J CO observations of low-mass young stellar objects. II. Distribution and origin of warm molecular gas.

VAN KEMPEN T.A., VAN DISHOECK E.F., GUESTEN R., KRISTENSEN L.E., SCHILKE P., HOGERHEIJDE M.R., BOLAND W., MENTEN K.M. and WYROWSKI F.

Abstract (from CDS):

The origin and heating mechanisms of warm (50<T<200K) molecular gas in low-mass young stellar objects (YSOs) are strongly debated. Both passive heating of the inner collapsing envelope by the protostellar luminosity as well as active heating by shocks and by UV associated with the outflows or accretion have been proposed. Most data so far have focussed on the colder gas component. We aim to characterize the warm gas within protosteller objects, and disentangle contributions from the (inner) envelope, bipolar outflows and the quiescent cloud. High-J CO maps (12CO J=6-5 and 7-6) of the immediate surroundings (up to 10000 AU) of eight low-mass YSOs are obtained with the CHAMP+ 650/850 GHz array receiver mounted on the APEX telescope. In addition, isotopologue observations of the 13CO J=6-5 transition and [CI] 3P2-3P1 line were taken. Strong quiescent narrow-line 12CO 6-5 and 7-6 emission is seen toward all protostars. In the case of HH 46 and Ced 110 IRS 4, the on-source emission originates in material heated by UV photons scattered in the outflow cavity and not just by passive heating in the inner envelope. Warm quiescent gas is also present along the outflows, heated by UV photons from shocks. This is clearly evident in BHR 71 for which quiescent emission becomes stronger at more distant outflow positions. Shock-heated warm gas is only detected for Class 0 flows and the more massive Class I sources such as HH 46. Outflow temperatures, estimated from the CO 6-5 and 3-2 line wings, are ∼100K, close to model predictions, with the exception of the L 1551 IRS 5 and IRAS 12496-7650, for which temperatures <50K are found. APEX-CHAMP+ is uniquely suited to directly probe the protostar's feedback on its accreting envelope gas in terms of heating, photodissociation, and outflow dispersal by mapping ∼1'x1' regions in high-J CO and [CI] lines. Photon-heating of the surrounding gas may prevent further collapse and limit stellar growth.

Abstract Copyright:

Journal keyword(s): astrochemistry - stars: formation - ISM: jets and outflows - submillimeter - stars: circumstellar matter - stars: pre-main sequence

VizieR on-line data: <Available at CDS (J/A+A/507/1425): Data never supplied>

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 - 2022
#notes
1 LDN 1448 DNe 03 22.5 +30 35           ~ 498 0
2 IRAS 03258+3104 Y*O 03 28 55.30 +31 14 27.8           ~ 163 1
3 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 434 3
4 BD+30 547 Y*O 03 28 57.2114503248 +31 14 19.076151444   10.73 9.98 9.1   G4V 101 1
5 EM* LkHA 270 TT* 03 29 17.6758022904 +31 22 44.892332544   16.344 14.639 13.994   K2/3IIIe 80 0
6 V* T Tau TT* 04 21 59.4319873992 +19 32 06.432393336   11.22 10.12 9.80   K0IV/Ve 1368 1
7 RAFGL 5123 Y*O 04 31 34.07736 +18 08 04.9020           K3V/M3III 838 0
8 IRAS 04361+2547 Y*O 04 39 13.89288 +25 53 20.8788           ~ 190 1
9 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1538 0
10 2MASS J08254384-5100326 Y*O 08 25 43.85 -51 00 32.7           ~ 307 1
11 IRAS 11051-7706 Y*O 11 06 46.025 -77 22 29.67           ~ 73 0
12 [PMG2001] NIR 76 Y*? 11 06 46.580 -77 22 32.56           ~ 55 0
13 [B2001b] IRS 2 Y*O 12 01 34.0 -65 08 44           ~ 25 0
14 BHR 71 MoC 12 01 36.810 -65 08 49.22           ~ 140 0
15 V* DK Cha Or* 12 53 17.2111480272 -77 07 10.736046012           F0 136 0
16 2MASS J19015545-3657231 Y*O 19 01 55.460 -36 57 23.13           ~ 92 2
17 [NWA2005] SMM 1B Y*O 19 01 56.41 -36 57 28.0           ~ 85 1

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2022.08.18-04:10:17

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