Thanks Pierre CO HCN Cx Hy Oz Nw

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Thanks Pierre ! CO HCN Cx. Hy. Oz. Nw me Molecules in galaxies Molecules

Thanks Pierre ! CO HCN Cx. Hy. Oz. Nw me Molecules in galaxies Molecules in ISM Molecules in comets

Molecules in comets Dominique Bockelée-Morvan Observatoire de Paris

Molecules in comets Dominique Bockelée-Morvan Observatoire de Paris

1864 first spectrum of a comet (Donati, comet Tempel C/1864 N 1) 1868 identification

1864 first spectrum of a comet (Donati, comet Tempel C/1864 N 1) 1868 identification of carbon and Swan bands C 2 (Huggins) 1881 identification of Na, other emissions of CH, CN, C 2, C 3 (comet Cruls-Tebbutt 1881 III) 1911 indentification of CO+ by de la Baume Pluvinel and Baldet (comet Morehouse 1908 III) 1941 idendification of OH (comet Cunningham 1941 I)

De la Baume and Baldet (1911) C 2 CO+ CN

De la Baume and Baldet (1911) C 2 CO+ CN

Hunt for molecules in comets (spectroscopy) § Visible and UV windows: essentially radicals and

Hunt for molecules in comets (spectroscopy) § Visible and UV windows: essentially radicals and ions exceptions : CO and S 2 tentative detection of phenanthene and pyrene in 1 P/Halley § IR 2 -5 mm window : fundamental bands of vibration hot bands of water (e. g. , n 3 -n 2) emission process : fluorescence § radio window (cm to submm): privileged tool cold atmospheres

A typical optical/near-IR comet spectrum 109 P/Swift-Tuttle Feldman et al. (2005)

A typical optical/near-IR comet spectrum 109 P/Swift-Tuttle Feldman et al. (2005)

UV cometary spectra HST spectra of C/1996 B 2 (Hyakutake) FUSE spectrum of C/2001

UV cometary spectra HST spectra of C/1996 B 2 (Hyakutake) FUSE spectrum of C/2001 A 2 (LINEAR) Feldman et al. (2002) Weaver et al. (1998)

Possible idendification of phenanthrene C 14 H 10 TKS/Vega @450 km 1 P/Halley Q/Q(H

Possible idendification of phenanthrene C 14 H 10 TKS/Vega @450 km 1 P/Halley Q/Q(H 2 O) = 1. 5 x 10 -3 Moreels et al. A&A 282, 643 Comparaison with laser-induced fluorescence spectra /jet-cooled conditions § Possible identification of pyrene C 16 H 10 : C 16 H 10 / C 14 H 10 = 0. 04 (Clairemidi et al. PSS 52, 761, 2004) § PAHs, if present, are released from grains (Joblin et al. 1997 PSS 45)

Hunt for molecules in comets (spectroscopy) § Visible and UV windows: essentially radicals and

Hunt for molecules in comets (spectroscopy) § Visible and UV windows: essentially radicals and ions exceptions : CO and S 2 tentative detection of phenanthene and pyrene in 1 P/Halley § IR 2 -5 mm window : fundamental bands of vibration hot bands of water (e. g. , n 3 -n 2) emission process : fluorescence § radio window (cm to submm): privileged tool cold atmospheres

IR spectroscopy IKS/VEGA Combes et al. (1986) Simple species : H 2 O, CO

IR spectroscopy IKS/VEGA Combes et al. (1986) Simple species : H 2 O, CO 2, H 2 CO, CH 3 OH 3. 3 -3. 5 mm band : CH-bearing species in gas phase unidentified compounds at 3. 42 mm 3. 28 mm band: PAHs ? PAHs bands at higher wavelengths not seen in Hale-Bopp ISO spectra

IR spectroscopy High spectral resolution ro-vibrational lines of CH 4, C 2 H 2,

IR spectroscopy High spectral resolution ro-vibrational lines of CH 4, C 2 H 2, C 2 H 6 CH 3 OH, HCN Unidentified lines need for detailed ro-vibrational structure and strength of CH 3 OH bands in 3 mm region + other organic species C/1999 H 1 (Lee) Keck/NIRSPEC Mumma et al. (2001)

Hunt for molecules in comets (spectroscopy) § Visible and UV windows: essentially radicals and

Hunt for molecules in comets (spectroscopy) § Visible and UV windows: essentially radicals and ions exceptions : CO and S 2 tentative detection of phenanthene and pyrene in 1 P/Halley § IR 2 -5 mm window : fundamental bands of vibration hot bands of water (e. g. , n 3 -n 2) emission process : fluorescence § radio window (cm to submm): privileged tool cold atmospheres

Radio spectroscopy § OH 18 cm lines (1973, comet Kohoutek, Nançay) § HCN 89

Radio spectroscopy § OH 18 cm lines (1973, comet Kohoutek, Nançay) § HCN 89 GHz (1985, comet Halley, IRAM 30 -m) § 19 molecules (not including isotopes, radicals, ions) now detected § many first identifications in comets Hyakutake and Hale-Bopp (in Hale Bopp: 10% of the 85 -375 GHz window with IRAM 30 m, Pd. Bi and CSO) § Isotopes: HDO, DCN, H 13 CN, HC 15 N, C 34 S, H 234 S § Radicals and ions: NS, CS, SO, CN, H 3 O+ , CO+

Historical radio spectra of comets First OH 18 cm detection (Nançay) Comet Kohoutek, Biraud

Historical radio spectra of comets First OH 18 cm detection (Nançay) Comet Kohoutek, Biraud et al. (1974) HCN J(1 -0) detection (IRAM 30 -m) Comet Halley, Despois et al. (1986)

New molecules in Hale-Bopp 230. 578 GHz Crovisier et al. 2004 A&A 418, L

New molecules in Hale-Bopp 230. 578 GHz Crovisier et al. 2004 A&A 418, L 35, 2004 Bockelée-Morvan et al. A&A 353, 1101, 2000 Ethylene glycol HOCH 2 OH 11 lines identified in 2003 when frequencies available in Cologne database

Odin observations H 2 O, H 218 O and NH 3 C/2001 Q 4

Odin observations H 2 O, H 218 O and NH 3 C/2001 Q 4 (NEAT) (cf N. Biver talk, tomorrow) H 218 O NH 3

Evidence for chemical diversity Diversity among Oort cloud comets No systematic differences between Oort

Evidence for chemical diversity Diversity among Oort cloud comets No systematic differences between Oort cloud and « Kuiper belt » comets Crovisier 2005

Upper limits for complex species Crovisier et al. A&A 418, 1141, 2004

Upper limits for complex species Crovisier et al. A&A 418, 1141, 2004

Molecular complexity § abundancesm when complexity k C 2 H 5 OH/CH 3 OH

Molecular complexity § abundancesm when complexity k C 2 H 5 OH/CH 3 OH <1/25 cyanopolyynes § but CH 4 ~ C 2 H 2 ~ C 2 H 6 § reduced alcohols wrt aldehydes CH 3 OH > H 2 CO OHCH 2 OH > CH 2 OHCHO Grain surface reactions ? Crovisier et al. A&A 418, 1141, 2004

Deuterium in comets C/1996 B 2 Hyakutake CSO In H 2 O: D/H =

Deuterium in comets C/1996 B 2 Hyakutake CSO In H 2 O: D/H = 3 10 -4 In HCN: D/H = 2. 3 10 -3 Atomic D detected (HST) In CH 3 OH, H 2 CO, NH 3, CH 4: upper limits of 10 -2 to a few 10 -2 Bockelée-Morvan et al. (1998) JCMT Meier et al. (1998)

Isotopic ratios

Isotopic ratios

Ortho-para ratios Table from Kawakita et al. 2004, Ap. J 601, 1152 C/2001 C/1999

Ortho-para ratios Table from Kawakita et al. 2004, Ap. J 601, 1152 C/2001 C/1999 C/2001 Q 4 S 4 H 1 A 2 (NEAT) (LINEAR) (Lee) (LINEAR) methane water Tspin = > ≈ = Recent results 33± 3 K Kawakita et al. 2005, Ap. J 623, L 49 30 K Dello Russo et al. 2005, Ap. J 621, 537 30 K idem 23± 4 K idem Why are all these temperatures similar? What is their signification?

What new from Deep Impact ? A’Hearn et al. 2005 Sciencexpress Deep Impact spectra

What new from Deep Impact ? A’Hearn et al. 2005 Sciencexpress Deep Impact spectra : large increase in the amount of organics compared to water 9 P/Tempel 1, 4 July 4 2005 § 4. 9 x 7. 6 km dark nucleus with low thermal inertia, low density, negligible strength § smooth and rough terrains, natural impact craters § DI impact: fine dust ejected, no dramatic increase in gas production (see Biver talk) Keller et al. 2005 Sciencexpress

§Strong increase in silicate emission after impact §Numerous bands reported : Al 2 O

§Strong increase in silicate emission after impact §Numerous bands reported : Al 2 O 3, PAHs, smectite clay, carbonates ….

PUB Deep Impact : les premiers resultats Olivier Groussin Observatoire de Meudon Lundi 7

PUB Deep Impact : les premiers resultats Olivier Groussin Observatoire de Meudon Lundi 7 Novembre 11 H

Open questions in comet chemistry § a lot of lines still unidentified HNC@Pd. Bi

Open questions in comet chemistry § a lot of lines still unidentified HNC@Pd. Bi § some radicals remain orphans : e. g. C 3, NS § origin of HNC : coma or nucleus product § origin of CN ? § nature of distributed sources of H 2 CO and CO § nature of dust organics ? § How abundances in the coma are related to abundances in the nucleus ? (chemical differenciation in the nucleus) § degree of compositional heterogeneity in comet nuclei

What the composition tells us about the origin of comet material? § molecular composition

What the composition tells us about the origin of comet material? § molecular composition present analogies with composition of star forming regions and interstellar ices § D/H ratios kept interstellar signatures § unequilibrated ortho/para ratios low-T formation (grain surface, ion-molecule processes) § highly processed material is present however (cristalline silicates) mixing with nebular products Chemical diversity in comets : how to explain it ?

Future prospects § current instrumentation : bright comets needed studies are focussing on chemical

Future prospects § current instrumentation : bright comets needed studies are focussing on chemical diversity/spatial distribution § ALMA : factor 10 increase in sensitivity large uv-coverage, instantaneous maps § Herschel Observatory: water, D/H ratio, bending modes of PAHs ? § Space missions : Deep impact, Rosetta