starspots

This test suite case evolves a 0.9 \({\rm M}_\odot\), solar metallicity (Z=0.02) model to an age of 24.63 Gyr using MESA’s implementation of the YREC (Yale Rotating Evolution Code) SPOTS formalism introduced by Somers et al. (2020; ApJ) Compare to Figure 15 in Section 7 of MESA Instrument Paper VI.

The impedence of the surface flux due to magnetic pressure from starspots is parameterized in the style of an atmospheric boundary modification. As first described by Somers et al. (2015; ApJ), the degree of “spottiness” on the stellar surface is characterized using two parameters:

  • SPOTF (hereafter fspot): a coverage fraction, or “spot filling factor” (in the notation of the YREC documentation); and

  • SPOTX (hereafter xspot): the temperature contrast between the spotted and unspotted regions: xspot = T_spot/T_photosphere.

The coverage fraction is set to fspot = 0.34 (for consistency with observations of low-mass stars: Cao et al., 2022) and the temperature contrast is set to xspot = 0.85 (also from fits to observations).

Detailed discussion of this functionality can be found in MESA Instrument Paper VI: Starspots.

A plot of the HR diagram for the problem is included below:

../_images/hr_starspots_001496.svg

Last-Updated: 09Aug2024 by Meridith Joyce

Last-Run: 06Aug2024 (MESA 7890d305) by pmocz on C916PXT6XW in 629 seconds using 8 threads.