Odin detection of O2

We present the detection of molecular oxygen with Odin toward the dense molecular core rho Oph A, which is part of a region of active star formation. The observed spectral line is the (N,J = 1,1-1,0) ground state transition of molecular oxygen at 119 GHz (2.5 mm wavelength). The center of the line is at the LSR velocity of a number of optically thin lines from other species in the region and the O2 line also has a very similar, narrow, line width. Within the 10 arcmin beam, the integrated line intensity is 28 mK km/s, which corresponds to 5 sigma of the rms noise. A standard LTE analysis results in an O2 abundance of 5E(-8), with an uncertainty of at least a factor of two. We show that standard methods, however, do not apply in this case, as the coupling of the Odin beam to the source structure needs to be accounted for. Preliminary model results indicate O2 abundances to be higher by one order of magnitude than suggested by the standard case. This model predicts the 487 GHz line of O2 to be easily detectable by the future Herschel-HIFI facility, but to be out of reach for observations on a shorter time scale with the Odin space observatory.Comment: 8 pages, 4 Postscript figures (3 in colour), uses iaus.cl

Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy)

The apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy) in March-April 2013 and January 2015, combined with the improved observational capabilities of submillimeter facilities, offered an opportunity to carry out sensitive compositional and isotopic studies of the volatiles in their coma. We observed comet Lovejoy with the IRAM 30m telescope between 13 and 26 January 2015, and with the Odin submillimeter space observatory on 29 January - 3 February 2015. We detected 22 molecules and several isotopologues. The H$_2^{16}$O and H$_2^{18}$O production rates measured with Odin follow a periodic pattern with a period of 0.94 days and an amplitude of ~25%. The inferred isotope ratios in comet Lovejoy are $^{16}$O/$^{18}$O = 499 $\pm$ 24 and D/H = 1.4 $\pm$ 0.4 $\times 10^{-4}$ in water, $^{32}$S/$^{34}$S = 24.7 $\pm$ 3.5 in CS, all compatible with terrestrial values. The ratio $^{12}$C/$^{13}$C = 109 $\pm$ 14 in HCN is marginally higher than terrestrial and $^{14}$N/$^{15}$N = 145 $\pm$ 12 in HCN is half the Earth ratio. Several upper limits for D/H or 12C/13C in other molecules are reported. From our observation of HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio in an Oort Cloud comet that is not larger than the terrestrial value. On the other hand, the observation of the same HDO line in the other Oort-cloud comet, C/2012 F6 (Lemmon), suggests a D/H value four times higher. Given the previous measurements of D/H in cometary water, this illustrates that a diversity in the D/H ratio and in the chemical composition, is present even within the same dynamical group of comets, suggesting that current dynamical groups contain comets formed at very different places or times in the early solar system.Comment: Accepted for publication in Astronomy and Astrophysic

From Molecular Oxygen to Primordial Molecules with the Odin Satellite

Odin is a mm/submm-wave-spectroscopy Astronomy and Aeronomy satellite. Its design life time was two years, but it has now operated successfully for more than six years. Its 1.1 m high-precision telescope, with a beam efficiency of 90%, has beamwidths of 10 arcmin and 2 arcmin at mm and submm wavelengths, respectively. It is equipped with a cryogenic receiver package of four tunable, SSB, submm Schottky mixers covering the 486-504 and 541-581 GHz frequency range, and a fixed-tuned HEMT receiver at a frequency of 118-119 GHz.Odin has discovered the elusive oxygen (O2) molecule at 119 GHz - the detection was made in the ρ Oph A molecular-cloud core. The O2 abundance, X(O2), is ≈5 710^{-8} - Larsson et al. (2007: A&A, 466, 999). Odin has also discovered water (H2O) at 557 GHz in the core of the Milky Way Galaxy - the Sgr A CircumNuclear Disk (CND)- and mapped its distribution in the Sgr A Complex including the +20 and +50 km s-1 Molecular Clouds - Sandqvist et al. (2006: J.Phys. Conf.Ser., 54, 72). Furthermore, devoting about 1,100 orbits (each of which contains 1 hour of observable astronomy time) Odin has performed a spectral-line survey of Orion KL in the ranges 487-492 and 542-577 GHz. There are 280 identified spectral lines from 38 species and 64 unidentified lines [Olofsson et al. (2007: A&A, 476, 791) and Persson et al. (2007: A&A, 476, 807)].Odin has searched for emission from the 557 GHz ortho-H2O line in six nearby starburst galaxies yielding three-sigma upper limits to the water abundance relative to H2 (NGC253

From Molecular Oxygen to Primordial Molecules with the Odin Satellite

Odin is a mm/submm-wave-spectroscopy Astronomy and Aeronomy satellite. Its design life time was two years, but it has now operated successfully for more than six years. Its 1.1 m high-precision telescope, with a beam efficiency of 90%, has beamwidths of 10 arcmin and 2 arcmin at mm and submm wavelengths, respectively. It is equipped with a cryogenic receiver package of four tunable, SSB, submm Schottky mixers covering the 486-504 and 541-581 GHz frequency range, and a fixed-tuned HEMT receiver at a frequency of 118-119 GHz. Odin has discovered the elusive oxygen (O2) molecule at 119 GHz - the detection was made in the ρ Oph A molecular-cloud core. The O2 abundance, X(O2), is ≈5×10^{-8} - Larsson et al. (2007: A&A, 466, 999). Odin has also discovered water (H2O) at 557 GHz in the core of the Milky Way Galaxy - the Sgr A CircumNuclear Disk (CND)- and mapped its distribution in the Sgr A Complex including the +20 and +50 km s-1 Molecular Clouds - Sandqvist et al. (2006: J.Phys. Conf.Ser., 54, 72). Furthermore, devoting about 1,100 orbits (each of which contains 1 hour of observable astronomy time) Odin has performed a spectral-line survey of Orion KL in the ranges 487-492 and 542-577 GHz. There are 280 identified spectral lines from 38 species and 64 unidentified lines [Olofsson et al. (2007: A&A, 476, 791) and Persson et al. (2007: A&A, 476, 807)]. Odin has searched for emission from the 557 GHz ortho-H2O line in six nearby starburst galaxies yielding three-sigma upper limits to the water abundance relative to H2 (NGC253 - <2.0×10^{-9}; IC342 -<2.6×10^{-9}; M82 -<1.7×10^{-9}; NGC 4258 -<1.3×10^{-8}; CenA -<7.8×10^{-9} and M51 -<2.4×10^{-9}) [Wilson et al. (2007: A&A, 469, 121)]. Odin has an ongoing project for studying the first phases of structure formation in the early universe. The presence of primordial molecules (e.g., HD, H2+, LiH, HeH+) is investigated by searching for spectral lines produced by resonant scattering of the cosmic microwave background (CMB). During the summer of 2004, Odin performed a spectral scan (547-578 GHz, 1 MHz resolution) towards two Wilkinson Microwave Anisotropy Probe CMB Hot Spots using 350 orbits (5 orbits per LO setting and point). No lines were detected down to an rms level of 65 mK. A new observing strategy was developed for a second observing session (430 orbits) during the winter of 2006/7 to accommodate for the spatial uncertainty of primordial clouds. The spectral range is 486.5-492.0 and 542.0-547.5 GHz (10 orbits per LO setting and point, 1 MHz resolution yielding an rms of about 30 mK). Analysis of these data is ongoing. This is a pilot programme for GTO time on ESA's Herschel Space Observatory, planned for launch in late 2008

Solar System observations with Odin

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Solar System observations with Odin

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Solar System observations with Odin

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Submillimetre observations of comets with Odin in 2001-2005

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