The ever–expanding depth and quality of photometric and spectroscopic observations of stellar populations increase the need for theoretical models in regions of age–composition parameter space that are largely unexplored at present .
Stellar evolution models that employ the most advanced physics and cover a wide range of compositions are needed to extract the most information from current observations of both resolved and unresolved stellar populations .
The Dartmouth Stellar Evolution Database is a collection of stellar evolution tracks and isochrones that spans a range of \mathrm { [ Fe / H ] } from –2.5 to +0.5 , \mathrm { [ \alpha / Fe ] } from –0.2 to +0.8 ( for \mathrm { [ Fe / H ] } \leq 0 ) or +0.2 ( for \mathrm { [ Fe / H ] } > 0 ) , and initial He mass fractions from Y=0.245 to 0.40 .
Stellar evolution tracks were computed for masses between 0.1 and 4 \mathrm { M _ { \odot } } allowing isochrones to be generated for ages as young as 250 Myr .
For the range in masses where the core He flash occurs , separate He-burning tracks were computed starting from the zero age horizontal branch .
The tracks and isochrones have been transformed to the observational plane in a variety of photometric systems including standard UBV ( RI ) _ { C } , Strömgren uvby , the Sloan Digital Sky Survey ugriz , the Two Micron All Sky Survey JH \mathrm { K _ { s } } , and Hubble Space Telescope ACS-WFC and WFPC2 .
The Dartmouth Stellar Evolution Database is accessible through a website http : //stellar.dartmouth.edu/ \sim models/ where all tracks , isochrones , and additional files can be downloaded .