The abundance of brown dwarfs

Journal article

The amount of mass contained in low-mass objects is investigated anew. Instead of using a mass-luminosity relation to convert a luminosity function to a mass function, I predict the mass-luminosity relation from assumed mass functions and the luminosity functions of Jahreiss and Wielen (1997) and Gould et al (1997). Comparison of the resulting mass-luminosity relations with data from binary stars constrains the permissible mass functions. If the mass function is assumed to be a power law, the best fitting slope lies either side of the critical slope, -2, below which the mass in low-mass objects is divergent, depending on the luminosity function adopted. If these power-law mass functions are truncated at 0.001Msun, the contribution to the local density of stars lies between 0.016 and 0.039 Msun pc^-3, in conformity with the density measured dynamically from Hipparcos stars. If the mass function is generalized from a power law to a low-order polynomial in log(M), the mass in stars with M<0.1Msun is either negligible or strongly divergent, depending on the order of the polynomial adopted.

Authors: Binney, J

• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 307
• Issue: 3
• Pages: L27-L30
• Publication date: 1998-09-08
• DOI: 10.1046/j.1365-8711.1999.02863.x
• EISSN: 1365-2966
• ISSN: 0035-8711
• Keywords: astro-ph