Good things come to those who wait: Watching donor stars evolve towards a mass-transfer instability

Abstract

Unstable mass transfer in binary systems can lead to transients such as luminous red novae (LRNe). Observations of such transients are valuable for understanding and testing models of mass transfer. For donor stars in the Hertzsprung gap, there can be a long phase of mass-transfer evolution before instability sets in. Only few case studies of such delayed dynamical instability (DDI) mass transfer exist. None consider the full pre-instability evolution and the effects thereof on the observable properties of a binary. We systematically analyse detailed models of stable and unstable mass transfer for Hertzsprung-gap donors. We focus on identifying observable evolutionary features characteristic of ultimately unstable mass transfer and not found in stable mass-transfer binaries. Our binary evolution models, calculated with the MESA code, cover initial donor masses between $2.5M_{\odot }$ and $10M_{\odot }$ and initial accretor-to-donor mass ratios between $0.1$ and $1$. We find that the pre-instability evolution is qualitatively the same for all DDI donor stars, consisting of a long slow dimming phase followed by a shorter phase of rapid brightening. The latter phase is powered by recombination of hydrogen and accompanied by a strong increase in effective temperature, unique to unstable mass-transfer binaries. We estimate that a significant fraction of the rapid brighteners should be detectable by Gaia throughout the Galaxy. We model the progenitors of LRNe M31-2015 and V838 Mon, find a higher initial donor mass for M31 2015 than past estimates, and propose a new scenario for V838 Mon in which the known tertiary star dominates the pre-outburst photometry and the outburst results from the DDI of a more massive primary star. This work provides a comprehensive framework linking theory to observations of transients and enables improved classification and prediction of mass-transfer events.

References in corpus (32)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• Common Envelope Evolution: Where we stand and how we can move forward
• Gaia Early Data Release 3: Photometric content and validation
• Exploring the Optical Transient Sky with the Palomar Transient Factory
• V1309 Scorpii: merger of a contact binary
• Formation of contact in massive close binaries
• The mysterious eruption of V838 Mon
• Identification of the Long-Sought Common-Envelope Events
• Eruptions of the V838 Mon type: stellar merger versus nuclear outburst models
• Nova Sagittarii 1994 #1 (V4332 Sagittarii): The Discovery and Evolution of an Unusual Luminous Red Variable Star
• Luminous Red Novae: Stellar Mergers or Giant Eruptions?
• Shock-powered light curves of luminous red novae as signatures of pre-dynamical mass loss in stellar mergers
• Common Envelope ejection for a Luminous Red Nova in M101
• Lessons from the Onset of a Common Envelope Episode: the Remarkable M31 2015 Luminous Red Nova Outburst
• SPIRITS: Uncovering Unusual Infrared Transients With Spitzer
• Massive-Star Mergers and the Recent Transient in NGC4490: A More Massive Cousin of V838 Mon and V1309 Sco
• Pre-explosion spiral mass loss of a binary star merger
• A single-degenerate model for the progenitor of the Type Ia supernova 2002ic
• Coping with loss: Stability of mass transfer from post-main sequence donor stars
• The SPIRITS sample of Luminous Infrared Transients: Uncovering Hidden Supernovae and Dusty Stellar Outbursts in Nearby Galaxies
• A Luminous Red Nova in M31 and its Progenitor System
• On the progenitor of V838 Monocerotis
• Progenitor, Precursor and Evolution of the Dusty Remnant of the Stellar Merger M31-LRN-2015
• Luminous Red Nova AT 2019zhd, a new merger in M 31
• Searching for the Next Galactic Luminous Red Nova

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