Observation of molecules in Comets with Odin and Deep Impact I Observation of the 557GHz water line in comets with Odin Monitoring of water outgassing, maps Other lines in bright comets: H 2 18 O and NH 3 Comets observed since Odin launch: II Radio observations of the target of Deep Impact Nicolas Biver, the Meudon comet team (LESIA, Paris Obs.) and the Odin team

ODIN (Sweden, France, Canada and Finland) 1.1m off-axis telescope 2.2' beam Tsys ~3000 K SSB Comets: H 2 O at 557GHz H 2 18 O at 547GHz NH 3 at 572 GHz H 2 17 O at 552GHz Launched: 20 Feb (polar orbit) End: April 2006? (Funding…) 50% Astronomy (63% time on target) 50% Aeronomy 153P/Ikeya-Zhang

Cometary water line at 557GHz: opaque…! self absorption in the foreground (comparison to HCN)

Monitoring of the outgassing of water of comet C/2003 K4 (LINEAR) with heliocentric distance: "turn-off" at ~2 AU

ODIN MIRO

Comet C/2001 Q4 (NEAT) observed with Odin Monitoring and Map of 15/16 may 2004

Comet 153P/Ikeya-Zhang: Modelling of the line shape and shift and comparison with observation from an extended map.

Odin findings Water production from Odin used for: 153P/Ikeya-Zhang:[H 2 O]/[H 2 18 O] = 450 ± 50 HDO/H 2 O < with CSO (Lecacheux et al. 2003) Preliminary results of : C/2001 Q4 (NEAT):[H 2 O]/[H 2 18 O] = 405 ± 35 C/2002 T7 (LINEAR): [H 2 O]/[H 2 18 O] = 510 ± 70 C/2004 Q2 (Machholz): [H 2 O]/[H 2 18 O] = 433 ± 21 HDO/H 2 O < with CSO Terrestrial ratio: 16 O/ 18 O = 499HDO/H 2 O = O/ 18 O ratio in cometary water with ODIN and D/H

Ammonia in comets From the ground:NH 3 at 24 GHz: C/1996 B2 (Hyakutake):[NH 3 ]/[H 2 O] = 0.6 % (NRAO) C/1995 O1 (Hale-Bopp):[NH 3 ]/[H 2 O] = ~1 % (Effelsberg, NRAO, NRO) 153P/Ikeya-Zhang:[NH 3 ]/[H 2 O] = 0.6 % (Effelsberg) C/2001 Q4 (NEAT):[NH 3 ]/[H 2 O] < 0.13 % (Effelsberg) C/2002 T7 (LINEAR):[NH 3 ]/[H 2 O] < 0.74 % (Effelsberg) (Hatchell et al. 2005, A&A) From NH 2 in the visible: Various comets: [NH 3 ]/[H 2 O]  0.5 % (Kawakita & Watanabe, 2002 ApJ 572, L177) With Odin: NH 3 (1-0) at 572 GHz: C/2001 Q4 (NEAT) [NH 3 ]/[H 2 O] = 0.3 % (Preliminary) C/2002 T7 (LINEAR) [NH 3 ]/[H 2 O] < 0.15 % (Preliminary) C/2004 Q2 (Machholz) Observations to be reduced, but of poor quality

Comets observed with ODIN since its launch: Comet/type:Dates Observations performedQ H2O max. C/2001 A2 (LINEAR) (LP)27 Apr. 2001, First observation 20 June-9 July 2001 Monitoring, maps P/Borrelly(JF p=6.9y)22-24 Sep. 2001, 5 Nov. 2001Deep Space 1 Flyby C/2000 WM 1 (LINEAR) (LP) 7 Dec. 2001, Map Mar. 2002Map P/Ikeya-Zhang (p=360y)22-28 Apr. 2002Map, H 2 18 O C/2002 X5 (Kudo-Fujikawa) (LP) 3-30 Mar. 2003Monitoring P/Schwassmann-Wachmann 1 (C)23-29 June 2003Search for H 2 O < P/Encke (JF p=3.3y) Nov.2003Small Maps C/2002 T7(LINEAR) (OC) 26 Jan.-29 May 2004Monitoring, H 2 18 O, NH 3 search C/2001 Q4 (NEAT) (OC)6 Mar.-16 May 2004Monitoring, H 2 18 O, NH 3, Map C/2003 K4(LINEAR) (OC) 27 Nov.-19 Feb month Monitoring C/2004 Q2 (Machholz) (LP) Jan. 2005Monitoring, H 2 18 O, NH 3 search P/Tempel 1 (JF p=5.5y) 18 June-7 Aug. 2005DeepImpact/Monitoring JF: Jupiter family, LP:Long Period, OC: Oort Cloud comet, C: Centaur comet; p= orb.period

Nançay observations of OH at 18cm: 1 hour per day from 4 March to 8 June &1-10 July. Detected on ~10days averages from 20 March to 8 June with peak Q H2O ~10 28 molec./s early May. Odin observations of H 2 O at 557 GHz (95 orbits): ~4 orbits every week 18 June – 7 August 2005 Small map on 18 th of June, 33 orbits July 3-5: Q H2O = 3 to 9×10 27 molec./s II - 9P/Tempel 1 target of Deep Impact Monitoring of the water outgassing:

1 month monitoring of comet 9P/Tempel 1: Before and after Deep Impact

Deep Impact on 9P/Tempel 1: Simulations of H 2 O observed by Odin First hypothesis: Big outburst of 11×10 32 molec. Lasting 1h (½ FWHM gaussian) (30000 tons of water – 2 days of activity or volume of a 100×30m crater, 50% ice; Qpeak×40 )  not seen Isotropic outgassing at 0.7 km/s Impact+67s from DI © NASA/JPL

H 2 O outgassing observed by Odin: nothing more than ~20% increase? Second hypothesis: ±isotropic "normal" outgassing + 15h burst (Qp+30%, total ~4000 tons) in a narrow jet in the plane of the sky to simulate the narrow peak > 0.24 K at 0 km/s.  Total Q H2O : +20% at impact + 1 day

Context of impact: ground based observations of 9P/Tempel 1 IRAM-30m (and CSO) observations: [1] daily monitoring 4.7 – 9.8 May: 1.7 day periodicity of Q HCN [2] daily monitoring 2.7 – 10.9 July: small increase of HCN and CH 3 OH line intensity and width lasting over a day following impact: Impact+50min from DI © NASA/JPL

IMPACT: IRAM-30m: HCN lines broader and slightly stronger on July 4.8 and 5.8, compared to July 2-3 and 6-10: new jet at ~1.2 km/s at h? (Seen also on CH 3 OH)

IMPACT: SUMMARY Odin: No big outburst of H 2 O, but perhaps a small jet in the plane of the sky (~4000 tons in 15h) IRAM and CSO (only upper limit on CH 3 OH at CSO):  No significant outburst just after impact but possible increase by 1.5 to 2.5 of HCN and CH 3 OH production rate (and abundance) – model dependent, especially on assumed temperature.  New jet at ~1.2 km/s towards the Sun/Earth: not seen in H 2 O?!  Need for a 4D model: 3 space dimensions (jet) and time-dependent for accurate interpretation, especially for optically thick H 2 O line at 557GHz. But limited S/N cannot provide good constraints on the parameters…  Need to discriminate impact effect from periodic variations (~40h in May) 9P/Tempel 1: Molecular abundances relative to water CH 3 OH 1.7±0.5% 3.2%7.2%*<2.7% 5-9 May July 6-11 July HCN 0.08 ± 0.01%0.13%0.17%*0.09% * Assuming increase of Temp. (20  40 K) and v exp (0.65  0.9 km/s) total