Thanks Pierre CO HCN Cx Hy Oz Nw
- Slides: 32
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
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
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)
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 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 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 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, 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 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 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 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 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 (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 cloud and « Kuiper belt » comets Crovisier 2005
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 <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 = 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
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 : 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 3, PAHs, smectite clay, carbonates ….
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 § 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 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 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
- Thanks pierre
- Acid 2-hidroxipropanoic
- Hcn formal charge
- Is hcn polar or nonpolar covalent bond
- Hcn lewis dot structure
- Hcn lewis structure
- Systematic approach to naming chemical compounds
- Ccl estructura de lewis
- Texas hcn workers compensation
- Carga formal
- Hcn geometria
- Hcn hybridization diagram
- Carbon monoxide lewis structure
- Lewis electron dot diagram
- Bonds broken minus bonds formed
- Formal charge of hcn
- Hcn + h2o
- Sudut segitiga planar
- Is hcn acid or base
- Fibre del purkinje
- Alxny notation
- Sof4 lewis structure
- Wzory elektronowe kwasów
- Hcn polar or nonpolar
- Intermolecular forces in sugar
- Hcn pi and sigma bonds
- Schéma de lewis hcn
- Legami idrogeno
- Thanks for solving the problem
- How to reply thanks
- First of all thanks to allah
- Thanks for your listening.
- Dear john last letter