2022A&A...666A.191W


Query : 2022A&A...666A.191W

2022A&A...666A.191W - Astronomy and Astrophysics, volume 666A, 191 (2022/10-1)

Confirmation of the outflow in L1451-mm: SiO line and CH3OH maser detections,.

WAKELAM V., COUTENS A., GRATIER P., VIDAL T.H.G. and VAYTET N.

Abstract (from CDS):


Context. The observational counterparts of theoretically predicted first hydrostatic cores (FHSC) have been searched for in the interstellar medium for nearly two decades now. Distinguishing them from other types of more evolved but still embedded objects remains a challenge because these objects have a short lifetime, are small, and embedded in a dense cocoon. One possible lead to finding them is the characterization of the outflows that are launched by these objects, which are assumed to have a low velocity and be small extent.
Aims. We observed the L1451-mm FHSC candidate with the NOEMA interferometer (and complementary IRAM 30m data) in order to study the emission of several molecules.
Methods. Molecular lines were reduced and analyzed with the GILDAS package network, the CASSIS software, and some python packages. A nonlocal thermodynamic equilibrium analysis of the CH3OH detected lines was performed to retrieve the physical conditions of the emitting region around the central source, together with the CH3OH, SiO, CS, and H2CO column densities.
Results. Of the targeted molecules, we detected lines of c-C3H2, CH3OH, CS, C34S, SO, DCN, DCO+, H2CO, HC3N, HDCO, and SiO. One of the methanol lines appears to be a maser line. The detection of this class I maser and the SiO line in L1451-mm support the presence of a low-velocity and compact outflow. The excitation conditions of the thermal lines of methanol are also compatible with shocks (H2 density of ∼3 × 106 cm–3 and a temperature higher than 40 K).
Conclusions. Although these low-velocity outflows are theoretically predicted by some models of FHSC, these models also predict the shock temperature to be below 20 K, that is, not evaporating methanol. In addition, the predicted velocities would not erode the grains and release silicon in the gas phase. We therefore conclude that these new observations favor the hypothesis that L1451-mm would be at a very early protostellar stage, launching an outflow nearly on the plane of the sky with a higher velocity than is observed.

Abstract Copyright: © V. Wakelam et al. 2022

Journal keyword(s): astrochemistry - stars: protostars - ISM: molecules - ISM: individual objects: L1451-mm - stars: low-mass

VizieR on-line data: <Available at CDS (J/A+A/666/A191): list.dat fits/*>

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 4C 28.07 QSO 02 37 52.40567519 +28 48 08.9899986     19.30 16.99   ~ 615 1
2 3C 84 Sy2 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 4017 3
3 NAME LDN 1451-mm cor 03 25 09.5 +30 23 51           ~ 50 0
4 LDN 1451 DNe 03 26.1 +30 10           ~ 55 0
5 [CAZ2013] NGC 1333 IRAS 2A1 smm 03 28 55.57 +31 14 37.1           ~ 10 0
6 [JCC87] IRAS 4 FIR 03 29 10.9 +31 13 26           ~ 478 0
7 ICRF J032915.3+351005 BLL 03 29 15.3548503584 +35 10 05.989666620       17.60   ~ 45 1
8 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1371 0
9 6C 033321+320838 Bla 03 36 30.10760267 +32 18 29.3422162     17.50 16.6   ~ 656 1
10 EM* LkHA 101 Em* 04 30 14.4355820328 +35 16 23.983198932   17.91 15.71 13.33   F 356 1
11 Barnard 220 DNe 04 41 38.8 +26 00 42           ~ 137 0
12 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 867 0
13 EM* MWC 349 ** 20 32 45.499080 +40 39 36.74124   15.88 13.15 12.13   Bep 802 0

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