Astronomical Institute "Anton Pannekoek", University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
2 SRON-Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
3 The Institute of Space and Astronautical Science (ISAS), Yoshino-dai 3-1-1, Sagamihara, Kanagawa 229-8510, Japan e-mail: firstname.lastname@example.org
Corresponding author: J. Cami, email@example.com
Accepted: 22 December 2000
We report the discovery in the ISO/SWS spectrum of the post-AGB star HR 4049 of emission bands due to 17O and 18O isotopes locked up in CO2 molecules. It is the first time these isotopomers are detected outside the solar system. Isotopic ratios derived in the optically thin limit are as low as 16O/17O and 16O/. These values are at least one order of magnitude lower than any previously determined isotopic ratio in any type of evolved star.
Key words: stars: AGB and post-AGB / stars: circumstellar matter / stars: individual: HR 4049 / stars: abundances / stars: late-type / infrared: stars
© ESO, 2001