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arXiv · 2610.31755

From Inspiral to Outburst: Modeling a Potential Luminous Red Nova from Betelgeuse

Abstract

Recent evidence suggests that Betelgeuse may host a stellar companion whose orbit will decay through tidal interactions, ultimately leading to engulfment and merger within the next several thousand years. If confirmed, this system could represent the nearest and best-characterized progenitor of a future luminous red nova (LRN). We investigate whether the shock-breakout and cooling emission preceding the LRN can be used to constrain the properties of the companion and its disruption within the stellar envelope. Using binary stellar evolution calculations, we evolve Betelgeuse with companions of $0.7$, $1.0$, and $2.0 M_\odot$ to the onset of common envelope evolution (CEE). We then perform one-dimensional radiation-hydrodynamic simulations that follow companion disruption, energy deposition, and shock propagation through the envelope. We find that the peak luminosity increases systematically with companion mass, from $2.44\times10^{41}$ to $6.17\times10^{41}$ erg s$^{-1}$ across the $0.7$-$2.0 M_\odot$ models, while the duration increases more modestly from $1.48$ to $1.99$ days and attains apparent magnitudes brighter than Venus as viewed from Earth. Tidal disruption contributes both kinetic energy and mass to the envelope, linking the companion's structure and mass to the energetics of the shock-heated ejecta. The monotonic luminosity sequence demonstrates that the early breakout emission can retain direct information about the engulfed companion. The interaction ejects $6.15$-$11.19 M_\odot$ of hydrogen-rich material, substantially modifying both the envelope structure and circumstellar environment prior to core collapse.

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Naunet Leonhardes-Barboza, Andrea Antoni, Morgan MacLeod, Angela Twum, Enrico Ramirez-Ruiz. 2026-10-22. From Inspiral to Outburst: Modeling a Potential Luminous Red Nova from Betelgeuse. https://arxiv.org/abs/2610.31755

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