Volume 530, June 2011
|Number of page(s)||14|
|Section||Stellar structure and evolution|
|Published online||27 April 2011|
Oxygen- and carbon-rich variable red giant populations in the Magellanic Clouds from EROS, OGLE, MACHO, and 2MASS photometry
Nicolaus Copernicus Astronomical Centre, Bartycka 18,
2 UPMC Université Paris 06, UMR 7095, Institut d’Astrophysique de Paris, 75014 Paris, France
e-mail: email@example.com; firstname.lastname@example.org; email@example.com
3 CNRS, UMR 7095, Institut d’Astrophysique de Paris, 75014 Paris, France
4 Adam Mickiewicz University Observatory, ul. Słoneczna 36, 60-286 Poznań, Poland
5 Research School of Astronomy & Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston ACT 2611, Australia
6 CEA, DSM, DAPNIA, Centre d’Études de Saclay, 91191 Gif-sur-Yvette Cedex, France
Received: 24 February 2010
Accepted: 8 March 2011
Context. The carbon-to-oxygen (C/O) ratio of asymptotic giant branch (AGB) stars constitutes an important index of evolutionary and environment/metallicity factor.
Aims. We develop a method for mass C/O classification of AGBs in photometric surveys without using periods.
Methods. For this purpose we rely on the slopes in the tracks of individual stars in the colour-magnitude diagram.
Results. We demonstrate that our method enables the separation of C-rich and O-rich AGB stars with little confusion. For the Magellanic Clouds we demonstrate that this method works for several photometric surveys and filter combinations. As we rely on no period identification, our results are relatively insensitive to the phase coverage, aliasing, and time-sampling problems that plague period analyses. For a subsample of our stars, we verify our C/O classification against published C/O catalogues. With our method we are able to produce C/O maps of the entire Magellanic Clouds.
Conclusions. Our purely photometric method for classification of C- and O-rich AGBs constitutes a method of choice for large, near-infrared photometric surveys. Because our method depends on the slope of colour-magnitude variation but not on magnitude zero point, it remains applicable to objects with unknown distances.
Key words: methods: data analysis / techniques: photometric / surveys / stars: oscillations / stars: AGB and post-AGB / Magellanic Clouds
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.