The Widespread Occurrence of Water Vapor in the Circumstellar Envelopes of Carbon-Rich Asymptotic Giant Branch Stars: First Results From a Survey With Herschel/HIFI
Artikel i vetenskaplig tidskrift, 2011
We report the preliminary results of a survey for water vapor in a sample of eight C stars with large mid-IR continuum fluxes: V384 Per, CIT 6, V Hya, Y CVn, IRAS 15194-5115, V Cyg, S Cep, and IRC+40540. This survey, performed using the HIFI instrument on board the Herschel Space Observatory, entailed observations of the lowest transitions of both ortho-and para-water: the 556.936 GHz 1(10)-1(01) and 1113.343 GHz 1(11)-0(00) transitions, respectively. Water vapor was unequivocally detected in all eight of the target stars. Prior to this survey, IRC+10216 was the only carbon-rich asymptotic giant branch (AGB) star from which thermal water emissions had been discovered, in that case with the use of the Submillimeter Wave Astronomy Satellite (SWAS). Our results indicate that IRC+10216 is not unusual, except insofar as its proximity to Earth leads to a large line flux that was detectable with SWAS. The water spectral line widths are typically similar to those of CO rotational lines, arguing against the vaporization of a Kuiper Belt analog being the general explanation for water vapor in carbon-rich AGB stars. There is no apparent correlation between the ratio of the integrated water line fluxes to the 6.3 mu m continuum flux-a ratio which measures the water outflow rate-and the total mass-loss rate for the stars in our sample.
lines
stars: abundances
winds
spectra
circumstellar matter
emission
stars: AGB and post-AGB
v-hydrae
submillimeter: stars
irc+10216
outflow
chemistry
mass-loss rates
discovery
Författare
D. A. Neufeld
Johns Hopkins University
E. Gonzalez-Alfonso
Universidad de Alcala
G. J. Melnick
Harvard-Smithsonian Center for Astrophysics
R. Szczerba
Polish Academy of Sciences
M. Schmidt
Polish Academy of Sciences
L. Decin
KU Leuven
Universiteit Van Amsterdam
J. Alcolea
Observatorio Astronómico Nacional (OAN)
A. de Koter
Universiteit Utrecht
Universiteit Van Amsterdam
Fredrik Schöier
Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium
V. Bujarrabal
Observatorio Astronómico Nacional (OAN)
J. Cernicharo
Centro de Astrobiologia (CAB)
C. Dominik
Universiteit Van Amsterdam
Radboud Universiteit
Kay Justtanont
Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik
A. P. Marston
Europeiska rymdorganisationen (ESA)
K. Menten
Max-Planck-Gesellschaft
Hans Olofsson
Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium
P. Planesas
Observatorio Astronómico Nacional (OAN)
Atacama Large Millimeter-submillimeter Array (ALMA)
D. Teyssier
Centro de Astrobiologia (CAB)
Lbfm Waters
Universiteit Van Amsterdam
Netherlands Institute for Space Research (SRON)
Astrophysical Journal Letters
2041-8205 (ISSN) 2041-8213 (eISSN)
Vol. 727 2 L29Ämneskategorier (SSIF 2011)
Astronomi, astrofysik och kosmologi
DOI
10.1088/2041-8205/727/2/L29