Unbiased Spectral SurveyUnbiased Spectral Surveyof the low massof the low massprotostar protostar IRAS 16293-2422IRAS 16293-2422

A. Castets et al.A. Castets et al.

Unique way of determining the molecular Unique way of determining the molecular content of astrophysical objectscontent of astrophysical objects

The study of excitation and line shapes of The study of excitation and line shapes of individual species can tell us about physical individual species can tell us about physical and chemical conditions in regions where and chemical conditions in regions where these species are coming fromthese species are coming from

Allow to understand the complex chemistry in Allow to understand the complex chemistry in this star forming region.this star forming region.

Why an unbiased spectral Why an unbiased spectral survey?survey?

Why IRAS16293-2422Why IRAS16293-2422

To date it is, among Class 0 sources, To date it is, among Class 0 sources, the object that has the brightest and the object that has the brightest and richest line spectrumrichest line spectrum

It has an inner hot core where T It has an inner hot core where T exceeds 100 K. The central object exceeds 100 K. The central object produces enough energy to produces enough energy to evaporate the molecules frozen in evaporate the molecules frozen in the grain mantles, being responsible the grain mantles, being responsible for its rich spectrumfor its rich spectrum

methyl formate : CH3OCHO

ethyl cyanide : C2H5CN dimethyl ether : CH3OCH3 acetaldehyde : CH3CHO

formic acid : HCOOH acetic acid : CH3COOH

methyl cyanide : CH3CN vinyl cyanide : C2H3CN

Cazaux et al., 2003

Hot core

High DeuterationHigh Deuteration

CH2DOH ~ 30%CHD2OH ~ 6%CH3OD ~ 3%

CD3OH ~ 1%

Parise et al., A&A, 2002

Parise et al., A&A, 2004

N(CH3OH)= 9.8x1015 cm-2

The ObservationsThe Observations

IRAM-30mIRAM-30m

Band Band (GHZ)(GHZ)

Resol Resol

(km/s)(km/s)rms rms (mK)(mK) StatusStatus

80 - 11580 - 115 1.16 – 0.821.16 – 0.82 4 – 64 – 6 donedone

129-177.5129-177.5 0.72 – 0.530.72 – 0.53 9 – 149 – 14 11.5 GHz 11.5 GHz missingmissing

197 - 265197 - 265 1.9 – 1.131.9 – 1.13 4 - 124 - 12 donedone

265 - 281265 - 281 1.41 – 1.331.41 – 1.33 6 – 126 – 12 7 GHz missing7 GHz missing

JCMTJCMT

328 – 328 – 366.5366.5 0.57 – 0.510.57 – 0.51 16 – 16 –

2222 donedone205.5 GHz planned – 187 GHz done (91%)

Example from the 100 GHz Example from the 100 GHz bandband

Example from the 230 GHz Example from the 230 GHz bandband

Example from the 345 GHz Example from the 345 GHz bandband

Construction of a database including all lines Construction of a database including all lines discovered in the survey including parameters like discovered in the survey including parameters like frequency, intensity, linewidth etc..frequency, intensity, linewidth etc..

Identification of lines and molecules from JPL, Lovas Identification of lines and molecules from JPL, Lovas and Cologne databases together with theoritical and Cologne databases together with theoritical calculations and experimental work.calculations and experimental work.

The survey will be published soon, and available on The survey will be published soon, and available on request one year after completion (2007)request one year after completion (2007)

Data Analysis

First raw identification of the molecular content

HDO abundance in IRAS16293 - Parise et al., 2005HDO abundance in IRAS16293 - Parise et al., 2005

4 lines from survey and the 1-0 at 464.924 GHz from JCMT4 lines from survey and the 1-0 at 464.924 GHz from JCMTAbundance ratio XAbundance ratio Xinin(HDO) = 10(HDO) = 10-7-7 and Xout(HDO) = 1.5x10-10

Complex molecules in IRAS16293 revisited: Complex molecules in IRAS16293 revisited: example of the dimethyl ether CHexample of the dimethyl ether CH33OCHOCH3 3

First results using the survey

T = 65 ±100 K

N(CH3OCH3) = 1.80 (± 2.77) 10

16 cm

-2

Berteloite, 2004

Cazaux et al., 2003

Dimethyl ether CH3OCH3

Cyanopolynes analysis - HCCyanopolynes analysis - HC33N, HCN, HC55N, HCN, HC77NN

Complex molecules Complex molecules

Deuterated Molécules Deuterated Molécules

Sulfurated moleculesSulfurated molecules

Basic Hydrocarbon Chemistry (CBasic Hydrocarbon Chemistry (C22H, CH, C33H, CH, C33HH22, C, C44H, H,

CC44HH22, C, C55H, CH, C66H...)H...)

Future use of this survey

Future work: Full Chemical modelFuture work: Full Chemical model

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

Next steps

Aurore Bacmann, L3AB, Observatoire de Bordeaux, FAurore Bacmann, L3AB, Observatoire de Bordeaux, F

Alain Castets, L3AB, Observatoire de Bordeaux, FAlain Castets, L3AB, Observatoire de Bordeaux, F

Emmanuel Caux, CESR, Toulouse, FEmmanuel Caux, CESR, Toulouse, F

Stéphanie Cazaux, Arcetri, IStéphanie Cazaux, Arcetri, I

Cecilia Ceccarelli, LAOG, Grenoble, FCecilia Ceccarelli, LAOG, Grenoble, F

Claudia Comito, MPIfR, Bonn, DClaudia Comito, MPIfR, Bonn, D

Frank Helmich, SRON, Gröningen, NLFrank Helmich, SRON, Gröningen, NL

Claudine Kahane, LAOG, Grenoble, FClaudine Kahane, LAOG, Grenoble, F

Bérengère Parise, CESR, Toulouse, FBérengère Parise, CESR, Toulouse, F

Peter Schilke, MPIfR, Bonn, DPeter Schilke, MPIfR, Bonn, D

Xander Tielens, Kapteyn Institut, Gröningen, NLXander Tielens, Kapteyn Institut, Gröningen, NL

Ewine van Dishoeck, Huygens Laboratory, Leiden, NLEwine van Dishoeck, Huygens Laboratory, Leiden, NL

Adam Walters, CESR, Toulouse, FAdam Walters, CESR, Toulouse, F

Valentine Wakelam, L3AB, Observatoire de Bordeaux, FValentine Wakelam, L3AB, Observatoire de Bordeaux, F

ConsortiumConsortium