English

Updated High-Temperature Opacities for the Dartmouth Stellar Evolution Program and their Effect on the Jao Gap Location

Solar and Stellar Astrophysics 2023-06-02 v1

Abstract

The Jao Gap, a 17 percent decrease in stellar density at MG10M_G \sim10 identified in both Gaia DR2 and EDR3 data, presents a new method to probe the interior structure of stars near the fully convective transition mass. The Gap is believed to originate from convective kissing instability wherein asymmetric production of 3^{3}He causes the core convective zone of a star to periodically expand and contract and consequently the stars' luminosity to vary. Modeling of the Gap has revealed a sensitivity in its magnitude to a population's metallicity primarily through opacity. Thus far, models of the Jao Gap have relied on OPAL high-temperature radiative opacities. Here we present updated synthetic population models tracing the Gap location modeled with the Dartmouth stellar evolution code using the OPLIB high-temperature radiative opacities. Use of these updated opacities changes the predicted location of the Jao Gap by 0.05\sim0.05 mag as compared to models which use the OPAL opacities. This difference is likely too small to be detectable in empirical data.

Keywords

Cite

@article{arxiv.2301.10798,
  title  = {Updated High-Temperature Opacities for the Dartmouth Stellar Evolution Program and their Effect on the Jao Gap Location},
  author = {Emily M. Boudreaux and Brian C. Chaboyer},
  journal= {arXiv preprint arXiv:2301.10798},
  year   = {2023}
}

Comments

15 pages, 13 figures; Accepted for publication in The Astrophysical Journal