Volume 555, July 2013
|Number of page(s)||7|
|Section||Galactic structure, stellar clusters and populations|
|Published online||11 July 2013|
Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way⋆
1 University of Hertfordshire, Physics Astronomy and Mathematics, Hatfield, AL10 9AB, UK
2 Dipartimento di Fisica, Univ. di Perugia, via Pascoli, 06123 Perugia, Italy
3 Osservatorio Astronomico di Teramo (INAF), via Maggini snc, 64100 Teramo, Italy
Received: 2 February 2013
Accepted: 16 May 2013
Context. Stars evolving along the asymptotic giant branch can become carbon-rich in the final part of their evolution. They replenish the inter-stellar medium with nuclear processed material via strong radiative stellar winds. The determination of the luminosity function of these stars, even if far from being conclusive, is extremely important for testing the reliability of theoretical models. In particular, strong constraints on the mixing treatment and the mass-loss rate can be derived.
Aims. We present an updated luminosity function of Galactic carbon stars (LFGCS) obtained from a re-analysis of available data already published in previous papers.
Methods. Starting from available near- and mid-infrared photometric data, we re-determined the selection criteria. Moreover, we took advantage of updated distance estimates and period–luminosity relations and we adopted a new formulation for the computation of bolometric corrections (BCs). This led us to collect an improved sample of carbon-rich sources from which we constructed an updated luminosity function.
Results. The LFGCS peaks at magnitudes around −4.9, confirming the results obtained in a previous work. Nevertheless, the luminosity function presents two symmetrical tails instead of the larger high-luminosity tail characterizing the former luminosity function.
Conclusions. The derived LFCGS matches the indications from recent theoretical evolutionary asymptotic giant branch models, thus confirming the validity of the choices of mixing treatment and mass-loss history. Moreover, we compare our new luminosity function with its counterpart in the Large Magellanic Cloud finding that the two distributions are very similar for dust-enshrouded sources, as expected from stellar evolutionary models. Finally, we derive a new fitting formula aimed to better determine BCs for C-stars.
Key words: stars: luminosity function, mass function / stars: AGB and post-AGB / stars: carbon / infrared: stars
Table 1 is available in electronic form at http://www.aanda.org
© ESO, 2013
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.