2001A&A...366..651V


Query : 2001A&A...366..651V

2001A&A...366..651V - Astronomy and Astrophysics, volume 366, 651-661 (2001/2-1)

H2 infrared emission and the formation of dense structures in the Orion molecular cloud.

VANNIER L., LEMAIRE J.L., FIELD D., PINEAU DES FORETS G., PIJPERS F.P. and ROUAN D.

Abstract (from CDS):

Observations are reported of IR emission of H2 from a region of the Orion molecular cloud (OMC 1) between the Becklin-Neugebauer object and IRc2 to the north and the Trapezium stars to the south. Data were obtained using the ESO 3.6 m telescope in the K-band around 2µm with the ADONIS adaptive optics system. Images of H2 v=1-0 S(1) show a spatial resolution of ∼0.15''. Detailed investigations of the distribution of sizes of structures in our images have been performed by area-perimeter analysis, Fourier analysis and brightness distribution studies. These demonstrate that structure is not fractal but shows a preferred scales of between 3x10–3 and 4x10–3pc. In an attempt to estimate the density in observed structures, predictions of both shock models and photodissociation region models have been compared with measured emission brightness in the H2 v=1-0 S(1) line. Magnetic (C-type) shocks with velocities of 30km/s and pre-shock densities of 106cm–3 yield the best representation of our data, notwithstanding significant discrepancies for the brightness ratio between v=2-1 S(1) and v=1-0 S(1) lines. Our results show that post-shock densities are several times 107cm–3. This is sufficiently high that the passage of C-type shocks in Orion yields gravitational instability which may in turn trigger star formation in the post-shock gas.

Abstract Copyright:

Journal keyword(s): ISM: individual objects: OMC 1 - ISM: kinematics and dynamics - ISM: molecules - shock waves - infrared: ISM: lines and bands

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 NAME OMC-1 MoC 05 35 14 -05 22.4           ~ 1170 2
2 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2299 1
3 V* V1330 Ori BY* 05 35 14.9155657944 -05 22 39.203240880   15.040 13.940   11.632 K4 73 0
4 [OW94] 154-240 Y*O 05 35 15.3915621696 -05 22 40.091425644         15.432 ~ 22 0
5 * tet01 Ori A Ae* 05 35 15.8254015008 -05 23 14.334699480 5.87 6.75 6.73 6.42 6.21 B0V 486 1
6 * tet01 Ori C SB* 05 35 16.4662967280 -05 23 22.921811880 4.20 5.15 5.13 4.91 4.73 O7Vp 1406 1
7 NAME Ori Trapezium OpC 05 35 16.5 -05 23 14           ~ 1621 1
8 * tet01 Ori D Y*O 05 35 17.2574479992 -05 23 16.570738104 6.08 6.79 6.70 6.40 6.20 B1.5Vp 329 0
9 GMR O Y*O 05 35 18.2310198552 -05 24 12.786954192     16.69 16.19 16.945 ~ 55 0
10 NAME Orion Molecular Cloud MoC 05 56 -01.8           ~ 1101 1
11 HD 71264 * 08 26 18.1522043376 -05 51 49.831718400   8.96 8.83     A0V 10 0
12 NGC 3603 OpC 11 15 10.8 -61 15 32           ~ 1068 1
13 NGC 7023 RNe 21 01 36.9 +68 09 48           ~ 704 0

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