相关论文: Binary coalescence from case A evolution -- merger…
This chapter describes the current state of models of individual blue stragglers. Stellar collisions, binary mergers (or coalescence), and partial or ongoing mass transfer have all been studied in some detail. The products of stellar…
Blue supergiants are the brightest stars in their host galaxies and yet their evolutionary status has been a long-standing problem in stellar astrophysics. In this pioneering work, we present a large sample of 59 early B-type supergiants in…
Stellar mergers and common-envelope evolution are fast (dynamical-timescale) interactions in binary stars that drastically alter their evolution. They are key to understanding a plethora of astrophysical phenomena. Stellar mergers are…
Stellar mergers are responsible for a large variety of astrophysical phenomena. They form blue straggler stars, give rise to spectacular transients, and produce some of the most massive stars in the Universe. Here, we focus on mergers from…
We use smoothed-particle hydrodynamics to examine differences between direct collisions of single stars and binary star mergers in their roles as possible blue straggler star formation mechanisms. We find in all cases that core helium in…
We study the production of main sequence mergers of tidally-synchronized primordial short-period binaries. The principal ingredients of our calculation are the angular momentum loss rates inferred from the spindown of open cluster stars and…
We present the results of a detailed, systematic stellar evolution study of binary mergers for blue supergiant (BSG) progenitors of Type II supernovae. In particular, these are the first evolutionary models that can simultaneously reproduce…
A six-dimensional parameter space based on high-resolution numerical simulations of isolated binary galaxy collisions has been constructed to investigate the dynamical friction timescales, $\tau_{\rm mer}$, for major mergers. Our…
Neutron star $-$ black hole (NSBH) merger events bring us new opportunities to constrain theories of stellar and binary evolution, and understand the nature of compact objects. In this work, we investigate the formation of merging NSBH…
We study the angular momentum evolution of binaries containing two white dwarfs which merge and become cool helium-rich supergiants. Our object is to compare predicted rotation velocities with observations of highly evolved stars believed…
The hydrodynamics of stellar collisions and mergers is discussed in the context of blue straggler formation. Emphasis is placed on the very important question of hydrodynamic mixing during the merger process. Recent results of…
Binary black hole mergers encode information about their environment and the astrophysical processes that led to their formation. Measuring the redshift dependence of their merger rate will help probe the formation and evolution of galaxies…
Collisions of main sequence stars occur frequently in dense star clusters. In open and globular clusters, these collisions produce merger remnants that may be observed as blue stragglers. Detailed theoretical models of this process require…
[Abbreviated] We have investigated the color-magnitude diagram of Omega Centauri and find that the blue main sequence (bMS) can be reproduced only by models that have a of helium abundance in the range Y=0.35-$0.40. To explain the faint…
Massive stars are usually found in binaries, and binaries with periods less than 10 days may have a preference for near equal component masses. In this paper we investigate the evolution of these binaries all the way to contact and the…
We report the results of new SPH calculations of parabolic collisions between two main-sequence stars in a globular cluster. Such collisions are directly relevant to the formation of blue stragglers. In particular, we consider parent stars…
The formation histories of compact binary mergers, especially stellar-mass binary-black hole mergers, have recently come under increased scrutiny and revision. In this paper we revisit the question of the dominant formation channel and…
Recent high-quality Hubble Space Telescope (HST) photometry shows that the main sequences (MS) stars of young star clusters form two discrete components in the color-magnitude diagram (CMD). Based on their distribution in the CMD, we show…
It was recently demonstrated that contact binaries occur in globular clusters (GCs) only immediately below turn-off point and in the region of blue straggler stars (BSs). In addition, observations indicate that at least a significant…
In open star clusters, where all members formed at about the same time, blue straggler stars are typically observed to be brighter and bluer than hydrogen-burning main-sequence stars, and therefore should already have evolved into giant…