Southern infrared proper motion survey
III. Constraining the mass function of low mass stars
Department of Astrophysics, Faculty of Science, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands e-mail: firstname.lastname@example.org;email@example.com;firstname.lastname@example.org
2 SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
Accepted: 14 April 2008
The stellar mass function is one of the fundamental distributions of stellar astrophysics. Its form at masses similar to the Sun was found by Salpeter (1955, ApJ, 121, 161) to be a power-law with a slope of α = 1.35. Since then the mass function in the field, in stellar clusters and in other galaxies has been studied to identify variation due to environment and mass range. Here we use results from previous papers in the SIPS series to constrain the mass function of low mass stars (0.075 < m < 0.2 ). We use simulations of the local low mass stellar population to model the results of the SIPS-II survey. We then vary the input parameters of these simulations (the exponent of the mass function α and a stellar birthrate parameter β) and compare the simulated survey results with those from the actual survey. After a correction for binarity and taking into account potential errors in our model we find that α = -0.62±0.26 for the quoted mass range.
Key words: stars: low mass, brown dwarfs / stars: luminosity function, mass function / astrometry
© ESO, 2008