In this study we present an analysis of a sample of field blue straggler ( BS ) stars that show high ultra violet emission in their spectral energy distributions ( SED ) : indication of a hot white dwarf ( WD ) companion to BS .
Using photometry available in the Sloan Digital Sky Survey ( SDSS ) and Galaxy Evolution Explorer ( GALEX ) surveys we identified 80 stars with UV excess .
To determine the parameter distributions ( mass , temperature and age ) of the WD companions , we developed a fitting routine that could fit binary model SEDs to the observed SED .
Results from this fit indicate the need for a hot WD companion to provide the excess UV flux .
The WD mass distribution peaks at \sim 0.4 M _ { \odot } , suggesting the primary formation channel of field BSs is case B mass transfer , i.e .
when the donor star is in red giant phase of its evolution .
Based on stellar evolutionary models , we estimate the lower limit of the binary mass transfer efficiency to be \beta \sim 0.5 .