[mesa-users] Change in evolutionary timescale between r8118 and r9575

[Matteo Dell'O. <mat...@fa...>]

Dear All,

I'm performing some basic comparisons in order to extend (using MESA 
r9575) a
dataset computed by means of MESA r8118.
I'm noticing some differences in the evolutionary timescale between the two
releases.

The case study I'd like to discuss is M = 1.40 Msun, Z = 0.01894, Y =
0.2674.
The inlist for the computations are attached to this message (inlist,
inlist_default, and inlist-nr) [the control  photo_interval in r9575 
replaces
the old photosteps], as well as the .net adopted.

It turns out that the stellar evolution computed by r9575 is 2% faster than
the one by r8118 (see attached plots). This is a very notable difference --
all input being the same -- and it
will have a relevant impact on grid-based estimates of stellar mass,
radius, and age.

I've no clue to trace the origin of the difference, since the release 
notes do
not highlight some changes which could alter so much the evolutionary 
timescale.

Could someone help by pointing out the changes (algorithms or default
values) occurred between the two versions?

Thanks in advance,
Matteo Dell'Omodarme

Sezione di Astronomia
Università di Pisa