2022A&A...666A..26B


Query : 2022A&A...666A..26B

2022A&A...666A..26B - Astronomy and Astrophysics, volume 666A, 26 (2022/10-1)

Surveying the inner structure of massive young stellar objects using L-band spectroscopy.

BARR A.G., LI J., BOOGERT A., LEE A., DEWITT C.N. and TIELENS A.G.G.M.

Abstract (from CDS):

We present results from a high spectral resolution (6 km s-1) survey of five massive protostars in the wavelength range of 2.95 and 3.25 µm, conducted with iSHELL at the InfraRed Telescope Facility (IRTF). Our targets are Mon R2 IRS 2, Mon R2 IRS 3, AFGL 2136, Orion BN and S140 IRS 1. Two of our five targets (Mon R2 IRS 3 and AFGL 2136) show transitions from organic species, with MonR2 IRS 3 showing HCN lines in emission, and AFGL 2136 showing HCN and C2H2 lines in absorption. The velocity of the emission lines of HCN of MonR2 IRS 3A are consistent with CO emission features in lines up to J = 26, as both are red-shifted with respect to the systemic velocity. Carbon monoxide lines also show blue-shifted absorption. This P-Cygni line profile, commonly observed towards massive young stellar objects, is likely due to an expanding shell, which is supported by sub-millimetre velocity maps of HCN. Alternatively HCN emission may arise from the upper layers of a disk photosphere, as has been suggested for the massive protostar AFGL 2591. Absorption lines in AFGL 2136 may either originate in foreground cloud or in the disk photosphere. For a foreground cloud, the data require that the foreground gas only covers the source partially (0.3) at 13 µm. In contrast, absorption lines at 3 and 7 µm require a covering factor of >0.9. Analysing the 13 µm HCN absorption lines in terms of absorption by gas in the photosphere of a disk, results in physical conditions that are consistent over all three vibrational modes. C2H2 absorption lines reveal an increasing temperature and abundance with decreasing wavelength, indicative of a radial abundance gradient. We conclude that the disk model is the best interpretation of the absorption lines of AFGL 2136.

Abstract Copyright: © A. G. Barr et al. 2022

Journal keyword(s): astrochemistry - stars: formation - circumstellar matter

VizieR on-line data: <Available at CDS (J/A+A/666/A26): list.dat sp/*>

Simbad objects: 21

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Number of rows : 21
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 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2334 0
2 JW 395 * 05 35 13.0257686136 -05 22 00.899262840   13.0 18.009   14.840 M2 29 0
3 [HAB84] 13 V* 05 35 13.0496305512 -05 22 15.204600660     17.49   14.084 M4.5 34 0
4 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2299 1
5 * sig Ori Y*O 05 38 44.7653828520 -02 36 00.283179888 2.54 3.58 3.79 3.87 4.11 O9.5V+B0.2V(n) 802 0
6 * sig Ori E Y*O 05 38 47.2050040320 -02 35 40.521424812 5.66 6.38 6.46 6.84 7.08 B2IV-Vp_He 458 0
7 * zet Ori ** 05 40 45.52666 -01 56 33.2649 0.50 1.56 1.77 1.85 2.05 O9.7Ib+B0III 357 0
8 * zet Ori A SB* 05 40 45.527143 -01 56 33.26036   1.79 1.90     O9.2IbvarNwk 666 0
9 NAME Mon R2 IRS 2 * 06 07 45.83 -06 22 53.5           B0 111 0
10 NAME Mon R2 HII 06 07 47.58 -06 22 42.6           ~ 744 2
11 NAME Mon R2 IRS 3 Y*O 06 07 47.8 -06 22 55           ~ 143 0
12 NAME Mon R2 IRS 3S IR 06 07 47.836 -06 22 56.29           ~ 14 0
13 NAME Mon R2 IRS 3N IR 06 07 47.855 -06 22 55.49           ~ 12 0
14 NAME Mon R2 IRS 3NE Y*O 06 07 47.87 -06 22 55.5           ~ 12 0
15 RAFGL 2136 Y*O 18 22 26.52888 -13 30 14.0400           ~ 285 0
16 * lam Aql PM* 19 06 14.9386542192 -04 52 57.225885348 3.07 3.34 3.43 3.46 3.55 B8.5V 225 0
17 RAFGL 2591 Y*O 20 29 24.8230 +40 11 19.590           ~ 622 0
18 IRAS 22176+6303 Y*O 22 19 18.23 +63 18 47.5           ~ 595 0
19 NAME SH 2-140 IRS 1 Y*O 22 19 18.277 +63 18 45.82           ~ 197 0
20 * alf Lac PM* 22 31 17.5014213452 +50 16 56.969913082 3.78 3.78 3.77 3.77 3.80 A1V 261 0
21 IRAS 23118+6110 Y*O 23 14 02.09473 +61 27 18.8460           ~ 376 0

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