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We quantify an evolutionary channel for single sdB stars based on mergers of binaries containing a red giant star and a lower mass main sequence or brown dwarf companion in our Galaxy. Population synthesis calculations that follow mergers during the common envelope phase of evolution of such systems reveal a population of rapidly rotating horizontal branch stars with a distribution of core masses between 0.32 Mo - 0.7 Mo that is strongly peaked between 0.47 Mo - 0.54 Mo. The high rotation rates in these stars are a natural consequence of the orbital angular momentum deposition during the merger and the subsequent stellar contraction of the merged object from the tip of the red giant branch. We suggest that centrifugally enhanced mass loss facilitated by the rapid rotation of these stars may lead to the formation of single sdB stars for some of these objects.
Common envelope (CE) phases in binary systems where the primary star reaches the tip of the red giant branch are discussed as a formation scenario for hot subluminous B-type (sdB) stars. For some of these objects, observations point to very low-mass
Over half of all observed hot subdwarf B (sdB) stars are found in binaries, and over half of these are found in close configurations with orbital periods of 10$ ,rm{d}$ or less. In order to estimate the companion masses in these predominantly single-
The discovery via gravitational waves of binary black hole systems with total masses greater than $60M_odot$ has raised interesting questions for stellar evolution theory. Among the most promising formation channels for these systems is one involving
Modelling dust formation in single stars evolving through the carbon-star stage of the asymptotic giant branch (AGB) reproduces well the mid-infrared colours and magnitudes of most of the C-rich sources in the Large Magellanic Cloud (LMC), apart from
We present a characterization of the dust in the Wolf-Rayet (WR) nebula RCW 58 around the WN8h star WR 40 using archival infrared (IR) observations from WISE and Herschel and radio observations from ATCA. We selected two clumps, free from contaminati