Following on from a question I asked ages ago here ( http://www.bautforum.com/space-astro...ion-grids.html ) I'm a bit perplexed by the latest Stellar Evolution Grids (the ones by A. Claret, 2004).
Stars from 0.8 to 2.0 solar masses don't appear to have an RGB branch in those grids. The 2.0 one sorta has a Horizontal Branch (you can see it if you plot Age vs L), but there isn't the big spike in luminosity before that, which one would expect to see if it had a proper RGB phase.
The other grids I was using before (by Schaerer, 1993) didn't have these phases for the lower mass stars either. However, grids by Charbonnel (VI, 1996) did have a horizontal branch and RGB phase for stars between 0.8 and 1.7 solar masses.
So presumably these stars do have HB and RGB phases, but if they do then why don't the major evolution grids show them?! Does it happen so quickly for a 2.0 solar mass star that it's been and gone between timesteps? Are there any more complete grids for these stars beyond the ones found at http://cdsarc.u-strasbg.fr/viz-bin/q...stellar+models ?