Water content and wind acceleration in the envelope around the oxygen-rich AGB star IK Tauri as seen by Herschel/HIFI
Journal article, 2010

During their asymptotic giant branch evolution, low-mass stars lose a significant fraction of their mass through an intense wind, enriching the interstellar medium with products of nucleosynthesis. We observed the nearby oxygen-rich asymptotic giant branch star IK Tau using the high-resolution HIFI spectrometer onboard Herschel. We report on the first detection of (H2O)-O-16 and the rarer isotopologues (H2O)-O-17 and (H2O)-O-18 in both the ortho and para states. We deduce a total water content (relative to molecular hydrogen) of 6.6 x 10(-5), and an ortho-to-para ratio of 3:1. These results are consistent with the formation of H2O in thermodynamical chemical equilibrium at photospheric temperatures, and does not require pulsationally induced non-equilibrium chemistry, vaporization of icy bodies or grain surface reactions. High-excitation lines of (CO)-C-12, (CO)-C-13, (SiO)-Si-28, (SiO)-Si-29, (SiO)-Si-30, HCN, and SO have also been detected. From the observed line widths, the acceleration region in the inner wind zone can be characterized, and we show that the wind acceleration is slower than hitherto anticipated.

w-hya

evolved

radiative transfer

stars

carbon stars

stars: AGB and post-AGB

circumstellar envelopes

submillimeter: stars

co

instrumentation: spectrographs

circumstellar matter

isotopic abundances

giant branch stars

mass-loss history

vapor

line emission

line: profiles

Author

L. Decin

University of Amsterdam

KU Leuven

Kay Justtanont

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

Elvire De Beck

KU Leuven

R. Lombaert

KU Leuven

A. de Koter

University of Amsterdam

Sterrekundig Instituut Utrecht

Lbfm Waters

University of Amsterdam

A. P. Marston

European Space Astronomy Centre (ESA)

D. Teyssier

European Space Astronomy Centre (ESA)

Fredrik Schöier

Chalmers, Earth and Space Sciences, Onsala Space Observatory

V. Bujarrabal

J. Alcolea

J. Cernicharo

Centro de Astrobiologia (CAB)

C. Dominik

University of Amsterdam

Radboud University

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

K. Menten

Max Planck Institute

D. A. Neufeld

Johns Hopkins University

Hans Olofsson

Chalmers, Earth and Space Sciences, Onsala Space Observatory

P. Planesas

Atacama Large Millimeter-submillimeter Array (ALMA)

M. Schmidt

Polish Academy of Sciences

R. Szczerba

Polish Academy of Sciences

T. de Graauw

Atacama Large Millimeter-submillimeter Array (ALMA)

F. Helmich

Netherlands Institute for Space Research (SRON)

P. Roelfsema

Netherlands Institute for Space Research (SRON)

P. Dieleman

Netherlands Institute for Space Research (SRON)

P. Morris

California Institute of Technology (Caltech)

J. D. Gallego

Centro Astronomico de Yebes

M. C. Diez-Gonzalez

Centro Astronomico de Yebes

E. Caux

Institut National des Sciences de l'Univers

University of Toulouse

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 521 1 Article Number: L4- L4

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201015069

More information

Latest update

10/30/2018