The role of stellar mass and mass functions in the ISM dust feedback

Núcleo de Astrofísica Teórica, CETEC, Universidade Cruzeiro do Sul, Rua Galvão Bueno 868, CEP 01506-000 São Paulo, Brazil e-mail: diego.goncalves@unicsul.br

Received: 10 May 2007
Accepted: 22 October 2007

Abstract

Context.The dust component of the interstellar medium (ISM) has been extensively studied in past decades. Late-type stars have been assumed as the main source of dust to the ISM, but recent observations show that supernova remnants may play a role in the ISM dust feedback.

Aims.In this work, we study the importance of low and high mass stars, along with their evolutionary phase, in the ISM dust feedback process. We also determine the changes in the obtained results considering different mass distribution functions and star formation history.

Methods.We describe a semi-empirical calculation of the relative importance of each star at each evolutionary phase in the dust ejection to the ISM. We compared the obtained results for two stellar mass distribution functions, the classic Salpeter initial mass function, and the current mass function. We used the evolutionary track models for each stellar mass and the empirical mass-loss rates and dust-to-gas ratio.

Results.We show that the relative contribution of each stellar mass depends on the used distribution. Ejecta from massive stars represent the most important objects for the ISM dust replenishment using the Salpeter IMF. On the other hand, for the present mass function, low and intermediate mass stars are dominant.

Conclusions.We confirm that late-type giant and supergiant stars dominate the ISM dust feedback in our Galaxy, but this may not the case for galaxies experiencing high star formation rates or at high redshifts. In those cases, SNe are dominant in the dust feedback process.