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Weighing an Interstellar Cloud: Orion GMC's Size and Mass Determination

This article discusses Harry Kroto's research on the Orion GMC and his methods for determining its size and mass, as well as addressing discrepancies in previous data. Kroto's findings reveal the presence of significant amounts of H2 and CO gases in the cloud. The article explores the implications of these findings in the context of interstellar cloud research.

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Weighing an Interstellar Cloud: Orion GMC's Size and Mass Determination

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  1. Harry Kroto 2004

  2. Let’s weigh Orion Harry Kroto 2004

  3. Orion GMC Harry Kroto 2004

  4. Orion GMC n(CO) = 10-1 Harry Kroto 2004

  5. Orion GMC n(CO) = 10-1 n(H2)/n(CO) = 104 Harry Kroto 2004

  6. Orion GMC n(CO) = 10-1 n(H2)/n(CO) = 104 n(H2) = 103 cm-3 Harry Kroto 2004

  7. Harry Kroto 2004

  8. Harry Kroto 2004

  9. Harry Kroto 2004

  10. Harry Kroto 2004

  11. Harry Kroto 2004

  12. 2o 8o Harry Kroto 2004

  13. Weighing an Interstellar Cloud 2o 8o Harry Kroto 2004

  14. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o 2o 8o Harry Kroto 2004

  15. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 2o 8o Harry Kroto 2004

  16. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 2o 8o Harry Kroto 2004

  17. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 2o 1o 8o Harry Kroto 2004

  18. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 2o 1o 1500 x sin 1o 8o Harry Kroto 2004

  19. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 2o 1o 1500 x sin 1o = 1500 x 0.0175 8o Harry Kroto 2004

  20. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 2o 1o 1500 x sin 1o = 1500 x 0.0175 = 26.2 8o Harry Kroto 2004

  21. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 2o 1o 1500 x sin 1o = 1500 x 0.0175 = 26.2 1o ~ 25 ly 8o Harry Kroto 2004

  22. Weighing an Interstellar Cloud Dimensions 2o x 2o x 8o n(H2) ~ 103 cm-3 Orion 1500ly away 50 ly 2o 1o 200 ly 1500 x sin 1o = 1500 x 0.0175 = 26.2 1o ~ 25 ly 8o Harry Kroto 2004

  23. NB 3.15 x107 secs in a year ~3x107 s Harry Kroto 2004

  24. NB 3.15 x107 secs in a year ~3x107 s 1ly ~ 3x107 x 3 x 1010~ 1018 cm Harry Kroto 2004

  25. NB 3.15 x107 secs in a year ~3x107 s 1ly ~ 3x107 x 3 x 1010~ 1018 cm Harry Kroto 2004

  26. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] Harry Kroto 2004

  27. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] Cloud size in ly Harry Kroto 2004

  28. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] Cloud size in ly Convert to cm3 Harry Kroto 2004

  29. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] Cloud size in ly Convert to cm3 Mass of H2 per cm3 in atomic mass units Harry Kroto 2004

  30. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] Cloud size in ly Convert to cm3 Mass of H2 per cm3 in atomic mass units Mo mass of Sun in grams Harry Kroto 2004

  31. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] Cloud size in ly Convert to cm3 Mass of H2 per cm3 in atomic mass units Mo mass of Sun in grams Avogadro number Harry Kroto 2004

  32. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] 5x105 x 1054 x 2 x 103 12 x 1056 Harry Kroto 2004

  33. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] 5x105 x 1054 x 2 x 103 12 x 1056 10 62 1056 Harry Kroto 2004

  34. [50 x 50 x 200] x [1018]3 x [2 x 103] [2x1033] [6x1023] 5x105 x 1054 x 2 x 103 12 x 1056 10 62 1056 = 106 Mo Harry Kroto 2004

  35. Main Results Harry Kroto 2004

  36. Main Results ca 5000 106Mo GMCs in Milky Way Harry Kroto 2004

  37. Main Results ca 5000 106Mo GMCs in Milky Way n(H2) = 1 - 104 Harry Kroto 2004

  38. Main Results ca 5000 106Mo GMCs in Milky Way n(H2) = 1 - 104 n(CO)/n(H2) = 10-4 Harry Kroto 2004

  39. Main Results ca 5000 106Mo GMCs in Milky Way n(H2) = 1 - 104 n(CO)/n(H2) = 10-4 n(13CO)/n(12CO) = 10-2 often optically thick Harry Kroto 2004

  40. Main Results ca 5000 106MoGMCs in Milky Way n(H2) = 1 - 104 n(CO)/n(H2) = 10-4 n(13CO)/n(12CO) = 10-2 often optically thick T = 10 - 100K Harry Kroto 2004

  41. Harry Kroto 2004

  42. Orion GMC n(12CO) = 10-3 n(13CO) = 10-3 !!!!!! Something wrong here n(13CO)/ n(12CO) = 10-2 12CO is optically thick n(13CO) = 10-3 correct n(12CO) = 10-1 n(H2)/n(12CO) = 104 n(H2) = 103 Harry Kroto 2004

  43. Orion GMC n(12CO) = 10-3 n(13CO) = 10-3 !!!!!! Something wrong here n(13CO)/ n(12CO) = 10-2 12CO is optically thick n(13CO) = 10-3 correct n(12CO) = 10-1 n(H2)/n(12CO) = 104 n(H2) = 103 Harry Kroto 2004

  44. Orion GMC n(12CO) = 10-3 n(13CO) = 10-3 !!!!!! Something wrong here n(13CO)/ n(12CO) = 10-2 12CO is optically thick n(13CO) = 10-3 correct n(12CO) = 10-1 n(H2)/n(12CO) = 104 n(H2) = 103 Harry Kroto 2004

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