1. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 NH 3 in comets with Mike Bird (RAIUB) William Sherwood (MPIfR) Wilhelm Altenhoff (MPIfR) Floris van der Tak (MPIfR) Karl Menten (MPIfR) Jennifer Hatchell (Exeter, ex-MPIfR)

2. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Motivation - NH 3 along with CO 2 and H 2 O is a constituent of cometary ices. -Nitrogen chemistry in early solar nebula poorly understood (N 2, NH 3 and N balance) - Spin temperature (from ortho/para ratio) implies formation temperature of ices

3. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Radio observations Photo: William Sherwood

4. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Previous radio detections C/1983 D IRAS-Araki-Alcock (Altenhoff et al. 1983) C/1996 B2 Hyakutake (Palmer et al. 1996, Green Bank) C/1995 O1 Hale-Bopp (Butler et al. 2002, Green Bank) C/1995 O1 Hale-Bopp (Hirota et al. 1999, Nobeyama) C/1995 O1 Hale-Bopp (Bird et al. 1997, Effelsberg) Direct detection Halley (Allen et al. 1987; Meier et al. 1994, Giotto) 6% 0.3% 1.8% 1.0-1.8% NH 3 /H 2 O 0.1-2%

5. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Optical detections of NH 2 (daughter) C/2002 T7 NH3 near 3 microns (Magee-Sauer et al. 2002) C/1999 S4 LINEAR (Kawakita et al. 2001) C/1995 O1 Hale-Bopp & 153P/Ikeya-Zhang (Kawakita et al. 2004) Kawakita et al. 2002 reanalysis of earlier NH 2 data OPR 3.33 Spin temp. 28K Spin temp. 30K NH 3 /H 2 O = 0.5% Infrared detections of NH 3 (lines often overlap with atmospheric absorptions) NH 3 /H 2 O = ???

6. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Targets 2001,2002,2004 Images: T.Vsoske, T.Lovejoy, S.Kim, and M.Jäger/G.Rheman C/2001 A2 (NEAT) C/2002 C1 (Ikeya-Zhang) (153P) C/2001 Q4 (NEAT) C/2002 T7 (LINEAR) 2001 2002 2004

7. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 OH 1665/1667 MHz

8. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 NH 3 24 GHz

9. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 NH 3 24 GHz NH 3 /H 2 O <= 0.5%

10. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004

11. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Conclusions NH 3 / H 2 O variable, 0.3-1.5% NH 3 / H 2 O <= 0.5% in many comets: Halley and Hale-Bopp may have been exceptional Consistency between radio / optically derived ratios

12. JENNIFER HATCHELL – UNIVERSITY OF EXETER Cardiff Astrochemistry Jan 2004 Upcoming comet missions Deep Impact (NASA) 9P/Tempel 1 launch date Jan 12 2005 Impactor + cameras July 4 2005 Rosetta (ESA) 67 P/Churyumov-Gerasimenko launched 2 March 2004 Lander 2014 Rosetta Philae (lander)