CHESS, Herschel Chemical Survey of Star Forming Regions

Transcription

1 CHESS, Herschel Chemical Survey of Star Forming Regions The Solar Type Protostar IRAS Emmanuel Caux CESR Toulouse on behalf the CHESS IRAS16293 sub-team A. Bacmann, E. Bergin, G. Blake, S. Bottinelli, A. Castets, C. Ceccarelli, J. Cernicharo, A. Coutens, N. Crimier, K. Demyk, C. Dominik, M. Gerin, T. Henning, P. Hennebelle, P. Hily-Blant, C. Kahane, A. Klotz, S. Maret, G. Melnick, L. Pagani, B. Parise, P. Schilke, C. Vastel, V. Wakelam, A. Walters

2 Studying the molecular content of SFR - The molecular complexity - How complex are complex molecules in SFR s? - When and how are they formed, what are their destiny? - Are they incorporated in the bricks forming the future planetary systems (meteorites, comets, planets )? - Lines are very powerful diagnostic tools - Different lines from the same molecule are excited in regions of different temperature and density - Different molecules are formed in regions with different internal and external conditions, and have different chemical history Unbiased Spectral Surveys of Star Forming Regions are a precious and unavoidable tool to study Star Formation

3 A Class- Solar-Type Protostar IRAS is a ~ 2 Lo Protostar in the ρ Ophiuchus complex (12 pc) Class are cold (< 3K) sources of a few M O, emitting mostly in the mm/ submm range

4 Evidence of grain mantle sublimation - At T dust > 1K the abundance of mantle molecules like H 2 CO and CH 3 OH jump by 2 or more orders of magnitude - The sublimated molecules show the super-deuteration phenomenon => they were formed during the Pre-Stellar Core phase hot corino Envelope temperature profile abundance jump at T>1K cold envelope CH 2 DOH / CH 3 OH >.5 CH 3 OD / CH 3 OH ~.4 CHD 2 OH / CH 3 OH ~.2 HDCO / H 2 CO ~.15 D 2 CO / H 2 CO >.5 CD 3 OH / CH 3 OH ~.3 Ceccarelli et al. 1998; Loinard et al. 2, Parise et al. 22 & 24

5 Hot Corinos - Compact (< 1 AU), warm (~ 1 K), dense (> 1 7 cm -3 ) enriched of Complex Organic Molecules (COMs) Kuan et al. 24; Bottinelli al. 24 Cazaux et al.. 23 Detected : methyl formate, dimethyl ether, formic acid, methyl cyanide, ethyl cyanide.

6 Why IRAS ? - It is the brightest solar-type Class source known to date - A lot of studies are already conducted towards this source, in all frequency ranges Envelope + binary system + a little of outflow in the HIFI beam, particularly at low frequencies

7 What Herschel HIFI brings? - Unbiased Spectral Survey in a frequency range mostly inaccessible from the ground - Complementary of an existing spectral survey in the mm range from IRAM-3m and JCMT (8-365 GHz) - In a very broad range ( GHz) with the same instrument, in the same observing (very good) conditions - Observations performed in SDP and PSP1 in March and April 21 (1a, 1b, 2b, 3b, 4a, 4b, 5a, part of 6a, 6b, 7a) - Still pending (September?) 2a, 3a, may be 5b, 7b

8 Data Processing - Data were processed with HIPE (see Ott et al. poster) up to Level-2 data + IA processing + deconvolution, or in CLASS after exporting level-2 data (see Maret et al. poster) - Sensitivity is as predicted by HSPOT in SIS bands (48-12 GHz) - Sensitivity is worse by about a factor 2 wrt HSPOT predictions in HEB bands (> 14 GHz) - Continuum is observed, and needed to derive columndensities of species only seen in absorption Data processing and data analysis are preliminary They can and they will be improved in the coming weeks

9 Continuum V-polar H-polar

10 Some broad range spectra 1a 1b 2b 3b

11 Some broad range spectra 4a 4b 5a 6b

12 Some broad range spectra 1a 1b 2b 3b

13 The obvious species Ceccarelli et al. 21, in prep. 5 CO + isotopes Caux et al. 21, in prep CI H 2 O

14 Line identification Band 1a an extremely rich spectrum with absorption lines

15 Species HCO + + isotopes + D SiO H 2 CO + isotopes + D HNC HCN + isotopes + D OCS H 2 S + isotopes + D N 2 H + H 2 O + isotopes + D NO CS + isotopes ND CO + isotopes CCH SO + isotopes PN SO 2 + isotopes H 2 CS CH 3 OH + isotopes CH 3 OCH 3 Band 1a : ~ 15 lines at 5

16 CS LTE modeling 1a Eup ~ 13 K 1b Eup ~ 18 K 3b Eup ~ 4 K 4a Eup ~ 5 K

17 Hydrides Frequency [GHz] T [K] T [K] CH Frequency [GHz] T [K] Frequency [GHz] HF HCl

18 N-Species T [K] Frequency [GHz] NH T [K] Frequency [GHz] T [K] Frequency [GHz] NH 2 NH

19 NH 2 N(NH 2 ) ~ cm -2

20 Deuterated N-Species Frequency [GHz] ND First detection of the ND radical (one tentative detection in Orion KL with Odin by Olofsson et al. 27).25.2 T [K] T [K] N(NH) ~ cm -2 N(ND) ~ cm Frequency [GHz] T [K] ND/NH ~ 45% Bacmann et al. 21, in prep NH 2 D Frequency [GHz] NHD

21 Deuterated water 6. Frequency [GHz] T [K] o-d 2 O Frequency [GHz] HDO T [K]

22 Heavy water OPR p-d 2 O : Butner et al. 27 CH 3 OD JCMT Herschel

23 Heavy water OPR Spectroscopy : CDMS ortho and para separation : CASSIS database ( Collision coefficients at 2 K (Wiesenfeld et al. in prep) Using T k = 2K and n(h 2 ) = 1 6 cm -3 N(o-D 2 O) = (1 ±.4) 1 12 cm -2 N(p-D 2 O) = (1.2 ±.5) 1 12 cm -2 OPR = 1.2 ±.9 Boltzman From ISO N(H 2 O) ~ D 2 O/H 2 O ~ = 6*(2J+1)/3*(2J+1) Vastel et al. 21, in prep

24 Conclusion HIFI is a very powerful and fast Spectral Survey machine Low-mass Protostars, although fainter than Highmass Protostars have a very rich submillimeter spectrum The scientific analysis of the IRAS16293 spectrum is just beginning, but as expected, is full of surprises, and the comparison with those of intermediate and high-mass Protostars is very promising.