UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Herschel observations of extreme OH/IR stars: The isotopic ratios of oxygen as a sign-post for the stellar mass

Justtanont, K; Barlow, MJ; Blommaert, J; Decin, L; Kerschbaum, F; Matsuura, M; Olofsson, H; ... Yates, J; + view all (2015) Herschel observations of extreme OH/IR stars: The isotopic ratios of oxygen as a sign-post for the stellar mass. Astronomy & Astrophysics , 578 , Article A11. 10.1051/0004-6361/201526270. Green open access

[thumbnail of Barlow_aa26270-15.pdf]
Preview
Text
Barlow_aa26270-15.pdf - Published version

Download (1MB) | Preview

Abstract

Aims. The late stages of stellar evolution are mainly governed by the mass of the stars. Low- and intermediate-mass stars lose copious amounts of mass during the asymptotic giant branch (AGB) which obscure the central star making it difficult to study the stellar spectra and determine the stellar mass. In this study, we present observational data that can be used to determine lower limits to the stellar mass. / Methods. Spectra of nine heavily reddened AGB stars taken by the Herschel Space Observatory display numerous molecular emission lines. The strongest emission lines are due to H2O. We search for the presence of isotopologues of H2O in these objects. / Results. We detected the 16O and 17O isotopologues of water in these stars, but lines due to H218O are absent. The lack of 18O is predicted by a scenario where the star has undergone hot-bottom burning which preferentially destroys 18O relative to 16O and 17O. From stellar evolution calculations, this process is thought to occur when the stellar mass is above 5 M⊙ for solar metallicity. Hence, observations of different isotopologues of H2O can be used to help determine the lower limit to the initial stellar mass. / Conclusions. From our observations, we deduce that these extreme OH/IR stars are intermediate-mass stars with masses of ≥5 M⊙. Their high mass-loss rates of ~10-4M⊙ yr-1 may affect the enrichment of the interstellar medium and the overall chemical evolution of our Galaxy.

Type: Article
Title: Herschel observations of extreme OH/IR stars: The isotopic ratios of oxygen as a sign-post for the stellar mass
Open access status: An open access version is available from UCL Discovery
DOI: 10.1051/0004-6361/201526270
Publisher version: https://doi.org/10.1051/0004-6361/201526270
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: stars: AGB and post-AGB / stars: mass-loss / circumstellar matter / stars: evolution / submillimeter: stars
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Computer Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/10093762
Downloads since deposit
3Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item