1. CH +, CH, and CN Emission from the Red Rectangle Lewis M. Hobbs, Julie A. Thorburn, D. G. York, Takeshi Oka, Department of Astronomy and Astrophysics, the University of Chicago, Theodore P. Snow, Center for Astrophysics and Space Astronomy, University of Colorado, and John Barentine, New Mexico State University and Apache Point Observatory 59 th Ohio State University International Symposium on Molecular Spectroscopy WI02, 2:05 pm, June 23, 2004

2. 1937 Birth of Molecular Astrophysics Theodore Dunham, Jr. 1897-1984Walter Sydney Adams, 1876-1956 T. Adams, Jr. PASP 49, 29 (1937) PAAS 9, 5 (1937) P. Swings & L. Rosenfeld, ApJ 86, 483 (1937) A.McKellar, PASP 52, 187, 312 (1940) 53, 233 (1941) CH CN Pub. Dom. Astroph. Obs. 7, 251 (1941) A. E. Douglas and G. Herzberg, ApJ 94, 381 (1941) CH +

3. Men’shchikov et al. A & A 393, 867 (2002)

4. Apache Point Observatory 3.5-meter 3,800–10,000 Å ; /  ~ 38,000 (8 km/s) S/N ~ 1000 7 nights, from Feb. 2001 to Feb. 2004 134 emission lines detected. 57 atomic, 76 molecular

5. CH + CH CN (0 - 0) 4236 Å Waelkens, van Winckel, Trams, Waters, A & A 256, L15 (1992) Balm and Jura, A & A 261, L25 (1992) Hall, Miles, Sarre, Fossey, Nature 358, 629 (1992) Bakkers, van Dishoeck, Waters, Schoenmaker, A & A 323, 469 (1997) (1  0) 3969 Å, (2-1) 4177 Å, (1-1) 4443 Å, (0- 1) 4793 Å, (1-2) 5029 Å, 52 lines up to J = 6 4307 Å 3 lines 3875 Å 24 lines up to N = 14

6. f = 5.45 × 10 -3 f = 1.08 × 10 -3

7. CH + (0 - 0) CH (0 - 0) CH + and CH are in different regions

8. CN up to N = 14

9. CH + Spontaneous emission time τ A → X τ ~ 1 μs Larsson, Siegbahn, CP 76, 175 (1983) v = 1→0 τ ~ 1 s Ornellas, Machado, JCP 84, 1296 (1985) J = 6→5 τ ~ 2.15 s Sun, Freed, JCP 88, 2659 (1988) μ A→X = 0.47 Debye μ 1→0 = 0.0105 Debye μ 0 = 1.656 Debye B 0 = 13.9302 cm -1 Critical density n c ~ 10 8 cm -3 ! NGC 7072 up to J = 6 Cernicharo, Liu, Gonzalez-Alfonso, Cox, Barlow, Lim, Swinyard, ApJ 483, L65 (1997)

10. Collisional thermalization ?? What is the collision partner ?? H, H 2, (He), (e - )

11. The Enigma of CH + Chemistry Production C + + H → CH + + hν 10 -17 cm 3 s -1 C + + H 2 → CH + + H Endothermic by 0.4 eV C + H 3 + → CH + + H 2 Destruction CH + + H → C + + H 2 Exothermic by 0.4 eV CH + + H 2 → CH 2 + + H Exothermic by 1.7 eV CH + + e - → C + H No way to thermalize CH + by collisions!!

12. Lambert, Danks, ApJ, 303, 401(1986) C + + H 2 * ↔ CH + + H v = 1 0.517 eV CH + + H 2 → CH 2 + + H k 1 n(C + )n(H 2 * ) = k -1 n(CH + )n(H) + k 2 n(CH + )n(H 2 ) The critical density should still be high > 10 8 cm -3

13. CN Spontaneous emission time τ A → X τ ~ 0.2 μs Bauschlicher, Langhoff, Taylor (1988) J = 14 → 13 τ ~ 12 s Langhoff, Bauschlicher(1989) μ 0 = 1.351 Debye B 0 = 1.89109 cm -1 Critical density n c ~ 10 8 cm -3 !

14. Hertzprung-Russell Diagram R ~ 300R 