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Caroline Herschel (1750-1848) one of the first professional women astronomer

Caroline Herschel (1750-1848) one of the first professional women astronomer she discovered 8 comets. ISO : water bands Crovisier et al. 1997 Science , 275 , 1904. Odin. First observations of rotational lines of water in comets. ISO : C/1995 O1 (Hale-Bopp). SWAS : C/1999 H1 (Lee).

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Caroline Herschel (1750-1848) one of the first professional women astronomer

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  1. Caroline Herschel (1750-1848) one of the first professional women astronomer she discovered 8 comets

  2. ISO : water bands Crovisier et al. 1997 Science, 275, 1904 Odin

  3. First observations of rotational lines of water in comets ISO : C/1995 O1 (Hale-Bopp) SWAS : C/1999 H1 (Lee)

  4. Profiles of thick and thin molecular lines in a comet Plain line : 557 GHz line of water from ODIN. THICK Dashed line : J(3-2) line of HCN from the CSO. THIN

  5. The D/H ratio in comets and in the Solar System  Earth oceans 

  6. Observations of HDO in comets C/1996 B2 (Hyakutake) CSO Bockelée-Morvan et al. 1998 Icarus 133, 147 C/1995 O1 (Hale-Bopp) JCMT Meier et al. 1998 Science279, 842

  7. HDO lines 225 GHz 241 GHz 600 GHz ground HIFI 81 GHz 509 GHz 895 GHz 465 GHz

  8. Qing-zhu Yin 2004, Science305, 1729 16O/18O in comets with ODIN 153P/Ikeya-Zhang: [H2O]/[H218O] = 450 ± 50 C/2001 Q4 (NEAT): [H2O]/[H218O] = 405 ± 35 C/2002 T7 (LINEAR): [H2O]/[H218O] = 510 ± 70 terrestrial ratio: 16O/18O = 499 Lecacheux et al. 2003 A&A, 402, L55

  9. Synthetic spectra of water for HIFI and SPIRE. diffraction-limited beam. Synthetic spectra of water for PACS. beam of 9.4". Comet at 1 AU from Earth and Sun, temperature = 60 K.

  10. A spectral survey of a comet with HIFI

  11. The spectrum of comet Hale-Bopp with water ice features observed with ISO/LWS Lellouch et al. 1998 A&A, 339, L9

  12. Cometary programmes for Herschel • Water in comets • Water in a sample of weak comets (HIFI) • Monitoring the water production rate as a function of r (HIFI) • Search for water in distant comets and weakly active objects - Relation between comets and asteroids. (HIFI) • Investigation of water excitation (HIFI SPIRE PACS) • Measurement of the D/H ratio (from HDO) (HIFI) • Dust in comets (SPIRE PACS) • correlation between dust and gas • investigation of the SED and search for solid features • Search for other species (hydrides) (HIFI) • minor species • radicals • ions

  13. Strategy of observations and scheduling - Select comets from the catalogue of short-period comets, taking into account - visibility (solar elongation) - expected activity (from preceding apparitions) - but Q[H2O] < 5. 1028 s-1 - Select unexpected comets as targets of opportunity - they would be the brightest comets - one or two per year with Q[H2O] > 1029 s-1 - notice of a few months, exceptionnally > 1 year

  14. Some "good" comets for Herschel 8P/TuttleJanuary 2008 Q[H2O] = 3. 1028 s-1D = 0.25 AU 46P/Wirtanen February 2008 Q[H2O] = 1. 1028 s-1 85P/Boethin December 2008 Q[H2O] = 3. 1028 s-1 67P/Churyu.-G December 2008 the Rosetta comet Q[H2O] = 5. 1027 s-1 22P/Kopff May 2009 Q[H2O] = 2.5 1028 s-1 81P/Wild 2 February 2010 the Stardust comet Q[H2O] = 1.3 1028 s-1 103P/Hartley 2October 2010 Q[H2O] = 1.2 1028 s-1D = 0.12 AU

  15. Photometric measurements of small bodies • Principle: combine measurement in visible range with measurement in thermal range  determine object’s diameter, albedo, and temperature • A program currently accomplished by Spitzer • Sensitivity of Herschel probably better than Spitzer, but much lower than ALMA • Objects typically reachable by Herschel : D ~ 300 km at 40 AU

  16. Helschel/SPIRE 250 micrometres Sensitivity (1  - 1h) = 0.6 mJy Detectability of TNOs with Herschel/SPIRE

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