1. Comets with ALMA N. Biver, LESIA, Paris Observatory I Comets composition Chemical investigation and taxonomy Monitoring of comet outgassing II Mapping of cometary atmospheres 3-D Gas and dust jets Physical properties of the coma and extended sources

2. Biver et al. 2002, E.M.P. 90, 323 I.ALMA and the composition of comets: Observing all types of comets (Kuiper Belt ones), new molecules

3. Measuring isotopic ratios in comets with ALMA Hersant et al. 2001, ApJ 554, 391 13 C/ 12 C: terrestrial in > 6 comets ALMA: H 13 CN, 13 CS, 13 CO, 13 CH 3 OH,… 34 S/ 32 S: ~ terrestrial in 2 comets ALMA: C 34 S, H 2 34 S 18 O/ 16 O: ~ terrestrial in 4 comets (H 2 O) 15 N/ 14 N: ~terrestrial in HCN Hale-Bopp but twice higher in CN in > 4 comets? ALMA: HC 15 N, H 15 NC? D/H: HDO/H 2 O 2× terrestrial in 3 comets, DCN/HCN 7× higher in Hale-Bopp HDO with ALMA: in bright comets (Herschel more sensitive) D/H in other molecules with ALMA (DCN, CH 2 DOH, HDCO, NH 2 D,…)

4. Cumulative number of molecules detected in comets as a function of abundance relative to water Crovisier et al. 2004, A&A 418, L35 RADIO

5. Detection of ethylene glycol in comet C/1995 O1 (Hale-Bopp) together with 3 other new species (HC 3 N, HCOOCH 3 and NH 2 CHO) Crovisier et al. 2004, A&A 418, L35

6. Comparison of comets chemical composition with interstellar medium Bockelée-Morvan et al. 2000, A&A 353, 1101

7. Progressive release of 9 molecules by comet C/1995 O1 (Hale-Bopp) - As it approached the Sun (left: 1995-1997) - As it receded from the Sun (right:1997-2001) Biver et al. 2002, E.M.P. 90, 5 ALMA: -Similar monitoring in less active comets (especially investigating transition between H 2 O and CO sublimation dominated regimes) -Distant activity of comets: detection of CO outgassing in comets active at 5-15 AU (mag. 16-17  Q CO =510 26 molec./s)

8. ALMA and the origins (composition) of comets (from line or dust integrated fluxes) I.1 Relative abundance of 6-8 molecules in a wide diversity of comets: Chemical difference between Oort clouds comets and Kuiper Belt (Jupiter Family) ones? I.2 Measuring molecular isotopic ratio: 34 S/ 32 S, 13 C/ 12 C, 15 N/ 14 N (issue with C 15 N and HC 15 N?) in moderately bright comets, D/H in several molecules (H 2 O, HCN, H 2 CO, NH 3, CH 3 OH…): differs between molecules due to different enrichment process  Place of formation of nuclei and proto-planetary nebula properties I.3 Searching for complex molecules: ~15 only observed before in Hale-Bopp and new molecules  Origin of solar system material I.4 Monitoring molecular and dust production rates with heliocentric distance: Retrieving nucleus composition from abundances in the coma  Structure of cometary ices

9. II Interferometric maps of cometary atmospheres ALMA will enable high resolution (50-100km) 3-D imaging of gas jets with simultaneous dust jets imaging and good time sampling thanks to its extensive u-v plane coverage (large number of baselines) Dust jets: 75% of the near nucleus coma signal in 1P/Halley (Giotto) Strong gas and dust jets in Hale-Bopp: (most of nuclear CO): determines the rotation period of 11h21m

10. Rotation of a CO jet in comet Hale-Bopp: 3-D information ALMA: HCN(3-2) or HCN(4-3) in several comets

11. Interferometric maps at 90 GHz and 220 GHz comet Hale-Bopp with IRAM Plateau de Bure 9, 11, 13 and 16 March 1997: continuum of dust and nucleus Altenhoff et al. 1999, A&A 348, 1020 Cometary « jets » with ALMA Investigating the coupling between dust and gas, and different gaseous species: Difference between night and day-time activity? Dust features predicted different from gas ones close to the nucleus? Variation of dust properties (opacity index, size distribution) with distance to the nucleus Measurement of gas (e.g. CH 3 OH) temperature and velocity field v

12. Molecules coming from a distributed source in the cometary atmospheres: ALMA will be used to measure the scalelengths (100-10000 km) H 2 CO: ~ 80% extended: thermo- degradation of polymers? CO: ~50% extended in Hale-Bopp; HNC, OCS: extended in Hale-Bopp? CS, SO, NS?: daughter molecules; Molecules released by grain sublimation

13. ALMA and the cometary atmospheres (interferometric mapping of physical properties) II.1 Measuring rotation from molecular lines (e.g. HCN(3-2), strongest): 3-D measurements thanks to the spectral resolution: rotation of several comets per year II.2 Comparing gaseous molecular jets and dust jets close to the nucleus Coupling of gas and dust in the near nucleus coma (sensitive to the nucleus shape), difference in day/night side activity: e.g. molecules only subliming on day side, difference in dust lifted by the gas,…  Cometary nuclei surface and gross properties (in addition to size) II.3 Gas temperature and velocity field in the inner coma (50-1000km):  Measuring adiabatic cooling and photolytic heating, T(r), v(r) II.4 Molecular density profiles n(r) :extended sources Characterizing the parents (grains, other molecules, chemical reaction) of such daughter molecules : CO, H 2 CO, CS, SO, HNC, NS…  New parent molecules, better characterization of productions

14. cometdateQ H2O [s -1 ]  [AU] Molecules detectable isotopesMoni- toring Jets imaging 22P/Kopff07/200910 28 0.8 ~6 - - Low res. 81P/Wild 203/201010 28 0.7 ~6 H 13 CN - Low res. 103P/Hartley210/20102.10 28 0.13 15 + new ones 13 C, 34 S, D, 15 N, (7 molec.) - High res., Dust, 6 molec. 45P/H.-M.-P.08/20112.10 27 0.07 ~10 13 C, 34 S - Med. res. 2P/Encke10/20136.10 27 0.5 ~8 - - Low res. New CometEvery year 1.10 29 0.6 ~15 13 C, 34 S, D, 15 N, in 7 molec. Up to 5 AU High res., Dust, 6 molec Great CometEvery 5 years 5.10 29 0.6 15 + new ones 13 C, 34 S, D, 15 N, >10molec. Up to 10AU High res., Dust, 10 molec Example of observable comets for ALMA