HERSCHEL* MEASUREMENTS OF MOLECULAR OXYGEN IN ORION

被引：116

作者：

Goldsmith, Paul F. ^{[1
]}

Liseau, Rene ^{[2
]}

Bell, Tom A. ^{[3
]}

Black, John H. ^{[2
]}

Chen, Jo-Hsin ^{[1
]}

Hollenbach, David ^{[4
]}

Kaufman, Michael J. ^{[5
]}

Li, Di ^{[1
]}

Lis, Dariusz C. ^{[6
]}

Melnick, Gary ^{[7
]}

Neufeld, David ^{[8
]}

Pagani, Laurent ^{[9
,10
]}

Snell, Ronald ^{[11
]}

Benz, Arnold O. ^{[12
]}

Bergin, Edwin ^{[13
]}

Bruderer, Simon ^{[12
]}

Caselli, Paola ^{[14
]}

Caux, Emmanuel ^{[15
,16
]}

Encrenaz, Pierre ^{[9
,10
]}

Falgarone, Edith ^{[17
,18
]}

Gerin, Maryvonne ^{[17
,18
]}

Goicoechea, Javier R. ^{[3
]}

Hjalmarson, Ake ^{[2
]}

Larsson, Bengt ^{[19
]}

Le Bourlot, Jacques ^{[20
]}

Le Petit, Franck ^{[20
]}

De Luca, Massimo ^{[20
]}

Nagy, Zsofia ^{[21
,22
]}

Roueff, Evelyne ^{[20
]}

Sandqvist, Aage ^{[19
]}

van der Tak, Floris ^{[21
,22
]}

van Dishoeck, Ewine F. ^{[23
,24
]}

Vastel, Charlotte ^{[15
,16
]}

Viti, Serena ^{[25
]}

Yildiz, Umut ^{[23
]}

机构：

[1] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[2] Chalmers Univ Technol, Onsala Space Observ, Dept Earth & Space Sci, SE-43992 Onsala, Sweden

[3] CSIC INTA, Ctr Astrobiol, Madrid 28850, Spain

[4] SETI Inst, Mountain View, CA 94043 USA

[5] San Jose State Univ, Dept Phys & Astron, San Jose, CA 95192 USA

[6] CALTECH, Cahill Ctr Astron & Astrophys 301 17, Pasadena, CA 91125 USA

[7] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[8] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA

[9] Observ Paris, CNRS, UMR8112, F-75014 Paris, France

[10] LERMA, F-75014 Paris, France

[11] Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA

[12] ETH, Inst Astron, CH-8092 Zurich, Switzerland

[13] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA

[14] Univ Leeds, Sch Phys & Astron, Leeds, W Yorkshire, England

[15] Univ Toulouse, UPS OMP, IRAP, Toulouse, France

[16] IRAP, CNRS, F-31028 Toulouse 4, France

[17] Ecole Normale Super, F-75231 Paris 05, France

[18] Observ Paris, UMR8112, CNRS, LRA LERMA, F-75231 Paris 05, France

[19] Stockholm Univ, AlbaNova Univ Ctr, Stockholm Observ, SE-10691 Stockholm, Sweden

[20] LUTH, Observ Paris, Paris, France

[21] Univ Groningen, Kapteyn Astron Inst, Groningen, Netherlands

[22] SRON Netherlands Inst Space Res, NL-9700 AV Groningen, Netherlands

[23] Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands

[24] Max Planck Inst Extraterr Phys, D-85748 Garching, Germany

[25] UCL, Dept Phys & Astron, London, England

来源：

ASTROPHYSICAL JOURNAL | 2011年 / 737卷 / 02期

基金：

美国国家航空航天局;

关键词：

astrochemistry; ISM: abundances; ISM: individual objects (Orion); ISM: molecules; submillimeter: ISM; DENSE INTERSTELLAR CLOUDS; WAVE-ASTRONOMY-SATELLITE; GAS-PHASE CHEMISTRY; APERTURE SYNTHESIS; UPPER LIMITS; DISSOCIATIVE RECOMBINATION; ROTATIONAL-EXCITATION; INELASTIC-COLLISIONS; HYDROGEN EMISSION; H-2; EMISSION;

D O I：

10.1088/0004-637X/737/2/96

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report observations of three rotational transitions of molecular oxygen (O-2) in emission from the H-2 Peak 1 position of vibrationally excited molecular hydrogen in Orion. We observed the 487 GHz, 774 GHz, and 1121 GHz lines using the Heterodyne Instrument for the Far Infrared on the Herschel Space Observatory, having velocities of 11 km s(-1) to 12 km s(-1) and widths of 3 km s(-1). The beam-averaged column density is N(O-2) = 6.5 x 10(16) cm(-2), and assuming that the source has an equal beam-filling factor for all transitions (beam widths 44, 28, and 19 ''), the relative line intensities imply a kinetic temperature between 65 K and 120 K. The fractional abundance of O-2 relative to H-2 is (0.3-7.3) x 10(-6). The unusual velocity suggests an association with a similar to 5 '' diameter source, denoted Peak A, the Western Clump, or MF4. The mass of this source is similar to 10 M-circle dot and the dust temperature is >= 150 K. Our preferred explanation of the enhanced O-2 abundance is that dust grains in this region are sufficiently warm (T >= 100 K) to desorb water ice and thus keep a significant fraction of elemental oxygen in the gas phase, with a significant fraction as O-2. For this small source, the line ratios require a temperature >= 180 K. The inferred O-2 column density similar or equal to 5 x 10(18) cm(-2) can be produced in Peak A, having N(H-2) similar or equal to 4 x 10(24) cm(-2). An alternative mechanism is a low-velocity (10-15 km s(-1)) C-shock, which can produce N(O-2) up to 10(17) cm(-2).

引用

页数：17

共 116 条

[1] Desorption of CO and O2 interstellar ice analogs [J].