Related papers: On the Energy Equation and Efficiency Parameter of…
We determine the possible masses and radii of the progenitors of white dwarfs in binaries from fits to detailed stellar evolution models and use these to reconstruct the mass-transfer phase in which the white dwarf was formed. We confirm…
The distinguishing feature of the evolution of close binary stars is the role played by the mass exchange between the component stars. Whether the mass transfer is dynamically stable is one of the essential questions in binary evolution. In…
One of the major uncertainties in close binary evolution is the efficiency of mass transfer beta: the fraction of transferred mass that is accreted by a secondary star. We attempt to constrain the mass-transfer efficiency for short-period…
The stability of mass transfer is critical in determining pathways towards various kinds of compact binaries, such as compact main-sequence white-dwarf binaries, and transients, such as double white-dwarf mergers and luminous red novae.…
We report extensive radial-velocity measurements of the two giant components of the detached, 104-day period binary system of Capella. Our highly accurate three-dimensional orbital solution based on all existing spectroscopic and…
We present a new model describing the evolution of triple stars which undergo common envelope evolution, using a combination of analytic and numerical techniques. The early stages of evolution are driven by dynamical friction with the…
Eclipsing close double white dwarf (WD) systems provide a unique opportunity to directly constrain hydrogen-envelope retention and test common-envelope (CE) evolution in low-mass stars, since they allow precise determinations of stellar…
The energy budget in common-envelope events (CEEs) is not well understood, with substantial uncertainty even over to what extent the recombination energy stored in ionised hydrogen and helium might be used to help envelope ejection. We…
Common envelope (CE) is an important phase in the evolution of many binary systems. Giant star / compact object interaction in binaries plays an important role in high-energy phenomena as well as in the evolution of their environment.…
We present an analytical model that describes the response of companion stars after being impacted by a supernova in a close binary system. This model captures key properties of the luminosity evolution obtained from 1D stellar evolution…
We carry out a comprehensive study of supernova ejecta-companion interaction in massive binary systems. We aim to physically understand the kinematics of the interaction and predict observational signatures. To do this we perform…
Some binary stars experience common envelope evolution, which is accompanied by drastic loss of angular momentum, mass, and orbital energy and which leaves behind close binaries often involving at least one white dwarf, neutron star, or…
We study the merging of massive stars inside a common envelope for binary systems consisting of a red supergiant with a mass of 15-20 Msun and a main-sequence companion of 1-5 Msun. We are particularly interested in the stage when the…
The recent discovery and analysis of a classical Cepheid in the well detached, double-lined, eclipsing binary OGLE-LMC-CEP0227, has provided the first determination of the dynamical mass of a classical Cepheid variable to an unprecedented…
At least one in five of all planetary nebulae are the product of a common envelope (CE) interaction, where the companion in-spirals into the envelope of an asymptotic giant branch (AGB) star ejecting the nebula and leaving behind a compact…
We review the fundamentals and the recent developments in understanding of common envelope physics. We report specifically on the progress that was made by the consideration of the recombination energy. This energy is found to be…
Stellar fundamental properties (masses, radii, effective temperatures) can be extracted from observations of eclipsing binary systems with remarkable precision, often better than 2%. Such precise measurements afford us the opportunity to…
We study the final stages of the common envelope (CE) evolution and find that a substantial fraction of the ejected mass does not reach the escape velocity. To reach this conclusion we use a self-similar solution under simplifying…
I consider three processes which enhance mass loss rate from a common envelope of a giant star with a main sequence or a white dwarf companion spiraling-in inside its envelope. I consider deposition of orbital energy and orbital angular…
Massive stars commonly form binaries that can evolve into compact systems via common envelope evolution (CEE), a critical but poorly understood phase -- especially when the companion is a neutron star. Understanding the drag force exerted…