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.



stars: AGB and post-AGB


circumstellar matter


stars: abundances

submillimeter: stars




mass-loss rates




D. A. Neufeld

Johns Hopkins University

E. Gonzalez-Alfonso

Universidad de Alcala

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

R. Szczerba

Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences

M. Schmidt

Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences

L. Decin

KU Leuven

Universiteit Van Amsterdam

J. Alcolea

Observatorio Astronomico Nacional

A. de Koter

Universiteit Van Amsterdam

Sterrekundig Instituut Utrecht

Fredrik Schöier

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

V. Bujarrabal

Observatorio Astronomico Nacional

J. Cernicharo

CSIC-INTA - Centro de Astrobiologia (CAB)

C. Dominik

Universiteit Van Amsterdam

Radboud Universiteit

Kay Justtanont

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

A. P. Marston

European Space Astronomy Centre

K. Menten

Max Planck-institutet

Hans Olofsson

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

P. Planesas

Observatorio Astronomico Nacional

Atacama Large Millimeter-submillimeter Array

D. Teyssier

CSIC-INTA - Centro de Astrobiologia (CAB)

Lbfm Waters

Universiteit Van Amsterdam

SRON Netherlands Institute for Space Research

Astrophysical Journal Letters

2041-8205 (ISSN) 2041-8213 (eISSN)

Vol. 727 L29


Astronomi, astrofysik och kosmologi