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Unraveling the Mystery of Oxygen in Interstellar Space

Explore the cosmic abundances and simplified chemistry of oxygen in gas phase, covering O2 recycling, cooling dark clouds, and theoretical detections. Question the reasons behind O2 deficiency despite its expected presence. Analyze reaction rates, UV ray penetration, turbulence effects, and more.

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Unraveling the Mystery of Oxygen in Interstellar Space

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  1. The deep search of O2 in interstellar space L. Pagani Observatoire de Paris-Meudon

  2. COSMIC ABUNDANCES

  3. Oxygen recycling Simplified oxygen chemistry in gas phase (from Prasad et al. 1987)

  4. How much of O2 ? 50 % of O in CO C/O » 0.4 50 % of O in O2 CO/ O2» 2 Cooling agent for dark clouds (Goldsmith & Langer 1978, ApJ 222, 881)

  5. Clavel et al. 1978, A&A 65, 435

  6. Goldsmith & Langer 1978, ApJ 222, 881

  7. From 1985 to 1997 : First searches from the ground O18O (234 GHz, NJ : 2101, Galactic sources) • Goldsmith et al,. 1985, ApJ 289, 613 • Liszt & van den Bout, 1985, ApJ 291, 178 • Pagani et al., 1993, A&A 274, L13 • Fuente et al., 1993, A&A 275, 558 • Maréchal et al., 1997, A&A 318, 252O2/CO < 0.1 (3 s) O16O (119 GHz, NJ : 1110, z > 0.02,  < 116 GHz) • Liszt, 1985, ApJ 298, 281L • Combes et al., 1991, A&A 248, 607 • Liszt, 1992, ApJ 386, 139 • Combes et al., 1997, A&A 327, L17O2/CO < 0.006 (3 s)

  8. 16O18O Search with POM-2 16O18O (NJ:21-01) line at 234 GHz is observable from the ground NGC 2264 (C18O and O18O) O2/CO < 0.09

  9. 16O18O Search with POM-2 L183, first false (tentative) detection…

  10. PIROG 8, a Balloon Experiment Launch He filling 60 cm telescope 425/440 GHz SIS receiver O2 (NJ:32-12) and 13CO (J:4-3) After Landing…

  11. Olofsson et al., 1998 A&A 339, L81 NGC 7538 13CO(4-3) NGC 7538 C18O and O2 W51 13CO(4-3) and O2 O2/CO < 0.04

  12. SWAS : O2 @ 487 GHz(NJ : 33-12) • SWAS did not detect O2 in quiescent cloud cores - • abundance limit of 3 x 10-7 rel. to H2 • (Goldsmith et al. 2000, ApJ 539, L123)

  13. Second false (tentative) detection in r Oph A SWAS Odin Goldsmith et al. 2002, ApJ 576, 814

  14. Odin, a Satellite with a 119 GHz rec. Swedish Satellite with contributions from France, Canada and Finland 1.1 m off-axis telescope, Schottky receivers, passively cooled

  15. Still no O2! (O2) < 5-10 -8

  16. No O2 in SMC (O2) < 1.3 -6 C/O = 0.16 and lower metallicity Wilson et al. 2005, A&A 403, L5

  17. Third false detection or real detection ? in r Oph A (again !) N(O2) = 8.4E14 cm-2 (O2) = 2.3E-8

  18. Ted Bergin's view of O2 chemistry Atomic Oxygen depletes on grains

  19. What reasons for O2 deficiency ? • Larger C/O ratio : 0.8 ? More ? • Deeper penetration of UV rays ? • Turbulence taking C+ deep inside ? • Turbulence + higher H abundance ? • Something wrong with the reaction rates ? (no! O + OH, I. Sims) • Depletion onto grains ? ((O2) (ice) < 1.5 10-5) • Reaction with PAHs ? (Joblin, Zermatt conf. 9/2003)… • See papers : • Vandenbussche et al. 1999, A&A 346, L57 • Goldsmith et al. 2000, ApJ 539, L123 • Bergin et al. 2000, ApJ 539, L129 • Casu et al. 2001, MNRAS 325, 826 • Spaan & van Dishoek, 2001, ApJ 548, L517 • Roberts & Herbst, 2002, A&A 395, 233 • Willacy et al., 2002, ApJ 573, L119

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