arXiv subjects

Miguel González-Bolívar

Publications and source records attributed to Miguel González-Bolívar.

5 recordsLinked to original sources

arXiv2026

Dust Formation in Common Envelope Binary Interactions -- III. Lightcurves

Luminous red novae are transient events thought to arise from common envelope binary interactions. In this paper, we perform post-processing light-curve calculations for two, 3D hydrodynamic simulations of common envelope events. These simulations model interactions between 1.7 $M_\odot$ and 3.7 $M_\odot$ asymptotic giant branch stars and a 0.6 $M_\odot$ compact companion, including dust nucleation. In both our simulations, which are carried out for 44 years under adiabatic conditions, we observe a bright, hot peak lasting $3-5$ years, primarily due to the expansion of the photosphere before and during inspiral. Additional peaks can be seen appearing at different times and for different viewing angles, due to the asymmetry of the interaction. Dust forms about $1-3$ years after the beginning of the simulated interaction and shortly afterwards we witness a sharp decline in the bolometric luminosity, followed by a partial recovery and a plateau with an effective temperature of $\sim$400 K. The dust photosphere reaches a size of $\sim$250 au by the end of the simulations, but we predict that between 100 and 200 years, the dust will become optically thin at visible wavelengths, revealing an inner, warmer photosphere. The lightcurves obtained have two, well-quantified, but large uncertainties: insufficient surface resolution primarily affecting the first 1-2 years of the simulated lightcurves and the adiabatic assumption that affects primarily the later years. We finally contextualise our simulations within a group of observed luminous red nova transients, drawing particular attention to the outburst of OGLE-2002-BLG-360 and AT 2025abao, which are the closest match to our simulation.

astro-ph.SR↗

arXiv2024

Dust formation in common envelope binary interactions -- II: 3D simulations with self-consistent dust formation

We performed numerical simulations of the common envelope (CE) interaction between thermally-pulsing asymptotic giant branch (AGB) stars of 1.7~\Msun and 3.7~\Msun, respectively, and a 0.6~\Msun compact companion. We use tabulated equations of state to take into account recombination energy. For the first time, formation and growth of dust is calculated explicitly, using a carbon dust nucleation network with a C/O abundance ratio of 2.5 (by number). The first dust grains appear within $\sim$1--3~yrs after the onset of the CE, forming an optically thick shell at $\sim$10--20~au, growing in thickness and radius to values of $\sim$400--500~au over $\sim$40~yrs, with temperatures around 400~K. Most dust is formed in unbound material, having little effect on mass ejection or orbital evolution. By the end of the simulations, the total dust yield is $\sim8.4\times10^{-3}$~\Msun and $\sim2.2\times10^{-2}$~\Msun for the CE with a 1.7~\Msun and a 3.7~\Msun AGB star, respectively, corresponding to a nucleation efficiency close to 100\%, if no dust destruction mechanism is considered. Despite comparable dust yields to single AGB stars, \textit{in CE ejections the dust forms a thousand times faster, over tens of years as opposed to tens of thousands of years}. This rapid dust formation may account for the shift in the infrared of the spectral energy distribution of some optical transients known as luminous red novae. Simulated dusty CEs support the idea that extreme carbon stars and "water fountains" may be objects observed after a CE event.

astro-ph.SR↗

arXiv2024

Dust formation during the interaction of binary stars by common envelope

We performed numerical simulations of the common envelope (CE) interaction between two intermediate-mass asymptotic giant branch (AGB) stars and their low-mass companions. For the first time, formation and growth of dust in the envelope is calculated explicitly. We find that the first dust grains appear as early as $\sim$1-3 yrs after the onset of the CE, and are smaller than grains formed later. As the simulations progress, a high-opacity dusty shell forms, resulting in the CE photosphere being up to an order of magnitude larger than it would be without the inclusion of dust. At the end of the simulations, the total dust yield is $0.0082~M_{\odot}$ ($0.022~M_{\odot}$) for a CE with a $1.7~M_{\odot}$ ($3.7~M_{\odot}$) AGB star. Dust formation does not substantially lead to more mass unbinding or substantially alter the orbital evolution.

astro-ph.SR↗

arXiv2024

Dust Formation in Common Envelope Binary Interaction -- I: 3D Simulations Using the Bowen Approximation

We carried out 3D smoothed particle hydrodynamics simulations of the common envelope binary interaction using the approximation of Bowen to calculate the dust opacity in order to investigate the resulting dust-driven accelerations. We have simulated two types of binary star: a 1.7 and a 3.7 $M_{\odot}$ thermally-pulsating, asymptotic giant branch stars with a 0.6 $M_{\odot}$ companion. We carried out simulations using both an ideal gas and a tabulated equations of state, with the latter considering the recombination energy of the envelope. We found that the dust-driven wind leads to a relatively small increase in the unbound gas, with the effect being smaller for the tabulated equation of state simulations and for the more massive primary. Dust acceleration does contribute to envelope expansion with only a slightly elongated morphology, if we believe the results from the tabulated equation of state as more reliable. The Bowen opacities in the outer envelopes of the two models, at late times, are large enough that the photosphere of the post-inspiral object is about ten times larger compared to the same without accounting for the dust opacities. As such, the prediction of the appearance of the transient would change substantially if dust is included.

astro-ph.SR↗

arXiv2022

Common envelopes in massive stars: Towards the role of radiation pressure and recombination energy in ejecting red supergiant envelopes

We perform 3D hydrodynamical simulations of a common-envelope event involving a 12 solar mass red supergiant donor. Massive stars are expected to be qualitatively different from low-mass stars as their envelopes have significant support from radiation pressure, which increases both the final separation and amount of mass ejected through the common-envelope interaction. We perform adiabatic simulations that include radiation energy through the equation of state, which results in ejecting 60 per cent more mass (up to two thirds of the total envelope mass becoming unbound, or more) and yield a 10 per cent larger final separation compared to simulations that assume an ideal gas. When also including recombination energy, we find that at least three quarters of the envelope, and possibly the entire envelope, may be unbound. The final separation further increases by almost 20 per cent. The additional amount of ejected material is mainly due to energy injected from helium recombination. Hydrogen recombination plays a comparatively small role, as it mainly occurs in gas that has already become unbound. We conclude that the internal energy of the envelope can be a significant energy source for ejecting the common envelope, but ultimately radiation transport and convection need to be included.

astro-ph.SR↗