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Related papers: Molecular oxygen in the rho Ophiuchi cloud

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We investigate the physical and chemical conditions in a typical star forming region, including an unbiased search for new molecules in a spectral region previously unobserved. Due to its proximity, the Orion KL region offers a unique…

This paper assesses the implications of a recent discovery (Jenkins 2009) that atomic oxygen is being depleted from diffuse interstellar gas at a rate that cannot be accounted for by its presence in silicate and metallic oxide particles. To…

Astrophysics of Galaxies · Physics 2014-11-20 D. C. B. Whittet

I review recent observations of molecular gas in the halo of the Milky Way and in the Magellanic Clouds. Far-ultraviolet absorption line studies of molecular hydrogen (H_2) with ORFEUS and FUSE have unveiled the presence of a diffuse…

Astrophysics · Physics 2007-05-23 Philipp Richter

The dominant form of oxygen in cold molecular clouds is gas-phase carbon monoxide (CO) and ice-phase water (H$_2$O). Yet, in planet-forming disks around young stars, gas-phase CO and H$_2$O are less abundant relative to their ISM values,…

Earth and Planetary Astrophysics · Physics 2023-09-12 Becky J. Williams , L. Ilsedore Cleeves , Christian Eistrup , Jon P. Ramsey

We report the detection of an emission feature at the 12 sigma level with FWHM line width of about 450 km/s toward the nearest quasi-stellar object, QSO Mrk 231. Based on observations with the IRAM 30 m telescope and the NOEMA…

Astrophysics of Galaxies · Physics 2020-02-12 Junzhi Wang , Di Li , Paul F. Goldsmith , Zhi-Yu Zhang , Yu Gao , Yong Shi , Shanghuo Li , Min Fang , Juan Li , Jiangshui Zhang

Cold cores in interstellar molecular clouds represent the very first phase in star formation. The physical conditions of these objects are studied in order to understand how molecular clouds evolve and how stellar masses are determined. The…

Astrophysics · Physics 2009-11-13 J. Harju , M. Juvela , S. Schlemmer , L. K. Haikala , K. Lehtinen , K. Mattila

Atomic carbon ([CI]) is a key species in the carbon chemistry of the interstellar medium (ISM). Using the Submillimeter Wave Astronomy Satellite (SWAS), we conducted a [CI]($^3$P$_1$--$^3$P$_0$) 492 GHz survey covering approximately 4…

We report new observations of molecular oxygen in absorption at z=0.685 in front of the radio source B0218+357. The lines at 56.3 and 118.7 GHz have been observed, redshifted to 33.4 and 70.5 GHz respectively, with the 12m at Kitt Peak, 43m…

Context. The chemistry of the diffuse interstellar medium rests upon three pillars: exothermic ion-neutral reactions (" cold chemistry "), endothermic neutral-neutral reactions with significant activation barriers (" warm chemistry "), and…

Context: Dark cloud chemical models usually predict large amounts of O2, often above observational limits. Aims: We investigate the reason for this discrepancy from a theoretical point of view, inspired by the studies of Jenkins and Whittet…

Solar and Stellar Astrophysics · Physics 2012-11-16 U. Hincelin , V. Wakelam , F. Hersant , S. Guilloteau , J. C. Loison , P. Honvault , J. Troe

Odin has successfully observed the molecular core rho Oph A in the 572.5 GHz rotational ground state line of ammonia, NH3 (J,K = 1,0 - 0,0). The interpretation of this result makes use of complementary molecular line data obtained from the…

We model the temperature and chemical structure of molecular clouds as a function of depth into the cloud, assuming a cloud of constant density n illuminated by an external FUV (6 eV < E < 13.6 eV) flux G_0 (scaling factor in multiples of…

Astrophysics · Physics 2011-02-11 David Hollenbach , Michael J. Kaufman , Edwin A. Bergin , Gary J. Melnick

Spectral line surveys are useful since they allow identification of new molecules and new lines in uniformly calibrated data sets. Nonetheless, large portions of the sub-millimetre spectral regime remain unexplored due to severe absorptions…

In front of the LMC molecular hydrogen is found in absorption near 0 km/s, being local disk gas, near +60 km/s in an intermediate velocity cloud, and near +120 km/s, in a high velocity halo cloud. The nature of the gas is discussed based on…

Astrophysics · Physics 2009-10-31 Hartmut Bluhm , Klaas. S. de Boer , Ole Marggraf , Philipp Richter

A substantial fraction of oxygen in diffuse clouds is unaccounted for by observations and is postulated to be in an unknown refractory form, referred to as unidentified depleted oxygen (UDO), which, depending on the local gas density, may…

We report the results of a search for molecular oxygen (O2) toward the Orion Bar, a prominent photodissociation region at the southern edge of the HII region created by the luminous Trapezium stars. We observed the spectral region around…

Recently the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O2, in the coma of Jupiter family comet 67P/Churyumov-Gerasimenko of O2/H2O =…

Earth and Planetary Astrophysics · Physics 2015-12-08 Martin Rubin , Kathrin Altwegg , Ewine F. van Dishoeck , Gerhard Schwehm

The most abundant interstellar molecule, molecular Hydrogen (H$_{2}$), is practically invisible in cold molecular clouds. Astronomers typically use carbon monoxide (CO) to trace the bulk distribution and mass of H$_{2}$ in our galaxy and…

Astrophysics of Galaxies · Physics 2023-11-23 Michael P. Busch

We present measurements of interstellar H_2 absorption lines in the continuum spectra of seven early-type stars in the Galactic disk at distances between 1 and 4 kpc. Five of these stars provide lines of sight through the Sagittarius spiral…

Astrophysics · Physics 2009-10-30 W. Van Dyke Dixon , Mark Hurwitz , Stuart Bowyer

We aim to take a census of molecular hydrogen emission line objects (MHOs) in the Rho Ophiuchi molecular cloud and to make the first systematic proper motion measurements of these objects in this region. Deep H2 near-infrared imaging is…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Zhang , W. Brandner , H. Wang , M. Gennaro , A. Bik , Th. Henning , R. Gredel , M. Smith , Th. Stanke