Bujarrabal, V., Alcolea, J., Soria-Ruiz, R., Planesas, P., Teyssier, D., Marston, A. P., Cernicharo, J., Decin, L., Dominik, C., Justtanont, K., de Koter, A., Melnick, G., Menten, K. M., Neufeld, D. A., Olofsson, H., Schmidt, M., Schoier, F. L., Szczerba, R. ORCID: 0000-0003-2886-4460, Waters, L. B. F. M., Quintana-Lacaci, G., Guesten, R., Gallego, J. D., Diez-Gonzalez, M. C., Barcia, A., Lopez-Fernandez, I., Wildeman, K., Tielens, A. G. G. M. and Jacobs, K. (2010). Herschel/HIFI observations of high-J CO transitions in the protoplanetary nebula CRL 618. Astron. Astrophys., 521. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 0004-6361

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Abstract

Aims. We aim to study the physical conditions, particularly the excitation state, of the intermediate-temperature gas components in the protoplanetary nebula CRL 618. These components are particularly important for understanding the evolution of the nebula. Methods. We performed Herschel/HIFI observations of several CO lines in the far-infrared/sub-mm in the protoplanetary nebula CRL 618. The high spectral resolution provided by HIFI allows measurement of the line profiles. Since the dynamics and structure of the nebula is well known from mm-wave interferometric maps, it is possible to identify the contributions of the different nebular components (fast bipolar outflows, double shells, compact slow shell) to the line profiles. The observation of these relatively high-energy transitions allows an accurate study of the excitation conditions in these components, particularly in the warm ones, which cannot be properly studied from the low-energy lines. Results. The (CO)-C-12 J = 16-15, 10-9, and 6-5 lines are easily detected in this source. Both (CO)-C-13 J = 10-9 and 6-5 are also detected. Wide profiles showing spectacular line wings have been found, particularly in (CO)-C-12 J = 16-15. Other lines observed simultaneously with CO are also shown. Our analysis of the CO high-J transitions, when compared with the existing models, confirms the very low expansion velocity of the central, dense component, which probably indicates that the shells ejected during the last AGB phases were driven by radiation pressure under a regime of maximum transfer of momentum. No contribution of the diffuse halo found from mm-wave data is identified in our spectra, because of its low temperature. We find that the fast bipolar outflow is quite hot, much hotter than previously estimated; for instance, gas flowing at 100 km s(-1) must have a temperature higher than similar to 200 K. Probably, this very fast outflow, with a kinematic age < 100 yr, has been accelerated by a shock and has not yet cooled down. The double empty shell found from mm-wave mapping must also be relatively hot, in agreement with the previous estimate.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Bujarrabal, V.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Alcolea, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Soria-Ruiz, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Planesas, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Teyssier, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Marston, A. P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Cernicharo, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Decin, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Dominik, C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Justtanont, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
de Koter, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Melnick, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Menten, K. M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Neufeld, D. A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Olofsson, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schmidt, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schoier, F. L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Szczerba, R.UNSPECIFIEDorcid.org/0000-0003-2886-4460UNSPECIFIED
Waters, L. B. F. M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Quintana-Lacaci, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Guesten, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gallego, J. D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Diez-Gonzalez, M. C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Barcia, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lopez-Fernandez, I.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wildeman, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Tielens, A. G. G. M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jacobs, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-494713
DOI: 10.1051/0004-6361/201015068
Journal or Publication Title: Astron. Astrophys.
Volume: 521
Date: 2010
Publisher: EDP SCIENCES S A
Place of Publication: LES ULIS CEDEX A
ISSN: 0004-6361
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
HETERODYNE INSTRUMENT; MOLECULAR ENVELOPE; CRL-618; DYNAMICS; FACILITY; APEXMultiple languages
Astronomy & AstrophysicsMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/49471

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