A comprehensive grid of massive binary evolution models for the Galaxy - Surface properties of post-mass transfer stars

TL;DR

This paper introduces a large grid of massive binary evolution models computed with MESA to explore how mass transfer shapes the surface properties of post-interaction stars across the main sequence, core helium burning, and pre-supernova stages. By tracking a detailed hydrogen-burning network and binary physics, the authors predict distinctive HRD positions and surface abundances for mass gainers and donors, including isotopic ratios, that differ from single-star evolution. The results indicate that mass gainers can become blue/yellow supergiants and donors often end as stripped or partially stripped stars, leading to a range of supernova progenitors from Type IIP to Ibc. These predictions enable observational diagnostics of binary interaction histories and provide a baseline for interpreting supernova progenitors and related phenomena.

Abstract

Massive stars often evolve in binary systems, in which binary interactions significantly affect their evolution. Massive stars in the Galaxy serve as valuable testbeds for this due to their proximity. We computed the evolution of more than 38000 galactic binary systems with initial primary star masses of 5...100 Msun. In this paper, we aim to investigate the surface properties of post-mass transfer mass donor and mass gainer stars through core hydrogen burning, core helium burning, and for the pre-supernova stage. The models are computed with MESA, incorporating detailed stellar and binary physics, including internal differential rotation, magnetic angular momentum transport, mass-dependent overshooting, stellar wind mass-loss, mass and angular momentum transfer and tidal interaction. They incorporate a new extensive nuclear network for hydrogen burning, which allows us to track the full range of hydrogen burning nucleosynthesis products, from the light elements to aluminum. The widest, non-interacting binary models in our grid effectively serve as single star models. We find that mass gainers and mass donors may evolve through long-lived blue and yellow supergiant stages during core helium burning where single stars of the same mass remain red supergiants. Furthermore, some of our gainers evolve into more luminous yellow and blue supergiants prior to core collapse than single stars, while some donors end their life as red or yellow supergiants, showing a rich diversity in supernova progenitors. We show that the surface elemental and isotopic abundances carry valuable information about a star's evolutionary history and can be used to distinguish binary interaction products from single stars. Our binary model grid may serve as a tool for identifying post-mass transfer stars and supernovae, and holds potential for population studies, supernova modeling, and guidance of future observations.

Figures (13)

• Figure 1: An overview of our binary evolution models with an initial primary mass of $12.6\,\mathrm{M_\odot}$. Each pixel represents one detailed binary evolution sequence, with colors indicating the status of the primary star in the midpoint of core helium burning (when central helium mass fraction is $Y_\mathrm{c}=0.5$). At this point, the secondary is a core hydrogen burning star. Black lines delineate the boundaries between different mass transfer cases, while the black-hatched region highlights models that will undergo another phase of mass transfer after primary's core helium depletion ("Late MT"). Models that are expected to merge, and models that did not converge due to unknown error are also indicated.
• Figure 2: Evolutionary tracks of primaries (left) and corresponding secondaries (right) for selected binary systems with $q_\mathrm{i}=0.8$, $P_\mathrm{i} = 5\, \rm d$ (top) and $P_\mathrm{i} = 398\, \rm d$ (bottom) in the Hertzsprung-Russell diagram. The initial masses of the stars are indicated. The color-coding represents the surface helium mass fraction. Diamonds mark the midpoint of core helium burning ($Y_\mathrm{c}=0.5$), stars indicate the point of central carbon depletion, and plus signs mark the termination point due to the expected merger. For reference, single star evolutionary tracks are shown as grey lines, plotted up to core helium depletion.
• Figure 3: Core hydrogen burning mass gainers after thermal relaxation (first column; see text), and of core helium burning single stars (second), mass gainers (third), and mass donors (fourth) in the Hertzsprung-Russell diagram, each shown at the midpoint of core helium burning ($Y_\mathrm{c}=0.5$). Thus, each data point represents one model sequence at a specific evolutionary stage. The color-coding represents surface helium mass fraction (top) and current hydrogen envelope mass (bottom), which is defined as the total mass subtracted by the helium core mass. Black lines represent evolutionary tracks for non-rotating single star models with their initial mass indicated. In the panels in the fourth column contain the data point for stripped star component in the black-hole binary imposter LB-1 Shenar2020Schuermann2022. Note that the colorbar range in the first column differs from that in the remaining columns.
• Figure 4: Mass gainer models at the midpoint of core helium burning ($Y_\mathrm{c}=0.5$) in the red supergiant region of the Hertzsprung-Russell diagram. The color-coding represents the surface helium mass fraction. Dashed lines indicate the region predicted by single star models.
• Figure 5: Single stars (left), mass gainers (middle), and mass donors (right) in the Hertzsprung-Russell diagram at core carbon depletion, which well represents the pre-supernova stage. The color-coding represents the effective temperature at the midpoint of core helium burning ($Y_\mathrm{c}=0.5$), the remaining hydrogen and helium envelope mass, and nitrogen-to-carbon ratio, from top to bottom. Data points are stacked such that those with higher $\log T_\mathrm{eff}$, $M_\mathrm{env}$, $\log \mathrm{(N/C)}$ appear above those with lower values. Evolutionary tracks for non-rotating single star models are also presented with their initial mass indicated. In the mass donor panel on the second row, the data point for SN 1993J progenitor is also shown Maund2004.