2010A&A...521L...3B


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.05CEST05:11:40

2010A&A...521L...3B - Astronomy and Astrophysics, volume 521, L3-3 (2010/10-1)

Herschel/HIFI observations of high-J CO transitions in the protoplanetary nebula CRL 618.

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., SCHOEIER F.L., SZCZERBA R., 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.

Abstract (from CDS):

We aim to study the physical conditions, particularly the excitation state, of the intermediate-temperature gas components in the protoplanetary nebula CRL618. These components are particularly important for understanding the evolution of the nebula. We performed Herschel/HIFI observations of several CO lines in the far-infrared/sub-mm in the protoplanetary nebula CRL618. 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. The 12CO J=16-15, 10-9, and 6-5 lines are easily detected in this source. Both 13CO J=10-9 and 6-5 are also detected. Wide profiles showing spectacular line wings have been found, particularly in 12CO 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 100km/s must have a temperature higher than ∼200K. Probably, this very fast outflow, with a kinematic age <100yr, 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.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - circumstellar matter - stars: mass-loss - planetary nebulae: general - planetary nebulae: individual: CRL 618

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 RAFGL 618 pA* 04 42 53.6245215366 +36 06 53.397219192   16.32   12.59   C-rich 954 0
2 Min 1-92 pA* 19 36 18.9292148675 +29 32 49.838032394 12.13 12.35 11.75 11.54   B0.5IV[e] 236 1
3 PN M 2-56 pA* 23 56 36.4101419399 +70 48 18.253127954   19.81 17 17.27 17.64 Be 88 0

    Equat.    Gal    SGal    Ecl

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2020.07.05-05:11:40

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