Image Details
Caption: Figure 2.
The loci in the ρ–T plane of the 0.1 (lower right), 0.3, 1, 3, and 9 M⊙ models (upper left) at the zero-age main sequence, defined here as the point where the central hydrogen mass fraction is 0.005 lower than the birth value. These are solar metallicity models using the base-model physics. The domains where radiation pressure equals gas pressure, and where zero-temperature degeneracy pressure equals gas pressure, are indicated by the respective red lines.
© 2026. The Author(s). Published by the American Astronomical Society.