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Unbiased Spectral Survey of the low mass protostar IRAS 16293-2422 A. Castets et al.

Unbiased Spectral Survey of the low mass protostar IRAS 16293-2422 A. Castets et al. Why an unbiased spectral survey?. Unique way of determining the molecular content of astrophysical objects

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Unbiased Spectral Survey of the low mass protostar IRAS 16293-2422 A. Castets et al.

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  1. Unbiased Spectral Surveyof the low massprotostar IRAS 16293-2422A. Castets et al.

  2. Why an unbiased spectral survey? • Unique way of determining the molecular content of astrophysical objects • The study of excitation and line shapes of individual species can tell us about physical and chemical conditions in regions where these species are coming from • Allow to understand the complex chemistry in this star forming region.

  3. Why IRAS16293-2422 • To date it is, among Class 0 sources, the object that has the brightest and richest line spectrum • It has an inner hot core where T exceeds 100 K. The central object produces enough energy to evaporate the molecules frozen in the grain mantles, being responsible for its rich spectrum

  4. Hot core Cazaux et al., 2003 methyl formate : CH3OCHO ethyl cyanide : C2H5CN dimethyl ether : CH3OCH3 acetaldehyde : CH3CHO formic acid : HCOOH acetic acid : CH3COOH methyl cyanide : CH3CN vinyl cyanide : C2H3CN

  5. High Deuteration CD3OH ~ 1% CH2DOH ~ 30% CHD2OH ~ 6% CH3OD ~ 3% Parise et al., A&A, 2004 Parise et al., A&A, 2002 N(CH3OH)= 9.8x1015 cm-2

  6. The Observations 205.5 GHz planned – 187 GHz done (91%)

  7. Example from the 100 GHz band

  8. Example from the 230 GHz band

  9. Example from the 345 GHz band

  10. Data Analysis • Construction of a database including all lines discovered in the survey including parameters like frequency, intensity, linewidth etc.. • Identification of lines and molecules from JPL, Lovas and Cologne databases together with theoritical calculations and experimental work. • The survey will be published soon, and available on request one year after completion (2007)

  11. First raw identification of the molecular content

  12. First results using the survey HDO abundance in IRAS16293 - Parise et al., 2005 4 lines from survey and the 1-0 at 464.924 GHz from JCMT Abundance ratio Xin(HDO) = 10-7 and Xout(HDO) = 1.5x10-10 Complex molecules in IRAS16293 revisited: example of the dimethyl ether CH3OCH3

  13. Dimethyl ether CH3OCH3 Cazaux et al., 2003 T = 65 ±100 K N(CH3OCH3)= 1.80 (± 2.77) 1016 cm-2 Berteloite, 2004

  14. Future use of this survey • Cyanopolynes analysis - HC3N, HC5N, HC7N • Complex molecules • Deuterated Molécules • Sulfurated molecules • Basic Hydrocarbon Chemistry (C2H, C3H, C3H2, C4H, C4H2, C5H, C6H...) Future work: Full Chemical model

  15. Next steps • Extension of the survey with the CSO, APEX and HSO-HIFI radio-telescopes. • Complete census of the molecular content of this object • Comparison of the molecular abundances observed in IRAS1623 with the predictions of actual chemical models • Comparison of the IRAS16293 chemical properties with those of massive hot-cores • Essential database for subsequent studies with other radiotelescopes (IRAM PdB, SMA, ALMA..)

  16. Consortium • Aurore Bacmann, L3AB, Observatoire de Bordeaux, F • Alain Castets, L3AB, Observatoire de Bordeaux, F • Emmanuel Caux, CESR, Toulouse, F • Stéphanie Cazaux, Arcetri, I • Cecilia Ceccarelli, LAOG, Grenoble, F • Claudia Comito, MPIfR, Bonn, D • Frank Helmich, SRON, Gröningen, NL • Claudine Kahane, LAOG, Grenoble, F • Bérengère Parise, CESR, Toulouse, F • Peter Schilke, MPIfR, Bonn, D • Xander Tielens, Kapteyn Institut, Gröningen, NL • Ewine van Dishoeck, Huygens Laboratory, Leiden, NL • Adam Walters, CESR, Toulouse, F • Valentine Wakelam, L3AB, Observatoire de Bordeaux, F

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