Exploring the Effects of Initial Stellar Parameters on the RGB Bump

As low mass stars (< 2.3 Msol) ascend the red-giant branch, they experience a brief period of contraction, paired with decreasing luminosity and increasing effective temperature, known as the red-giant branch bump. This period ends when the hydrogen-burning shell surpasses the mean-molecular weight discontinuity. The effects of the star's initial parameters on the behavior of the bump is not fully understood. I used MESA to model a grid of stars, varying in mass and metallicity, in order to provide insight into the inner workings of red-giants during this evolutionary period and to compare the bump across a range of initial stellar parameters. Analysis of the MESA data shows possible relationships between a star’s initial parameters and the state of its internal structure during the period of the bump. These relationships may provide insight into the mechanisms that govern the bump and its effect on the evolution of these low-mass stars.