Related papers: The Past and Future History of Regulus
Using stellar binary population synthesis code we calculate the production rates and lifetimes of several types of possible GRB progenitors. We consider mergers of double neutron stars, black hole neutron stars, black hole white dwarfs and…
The relation between the zero-age main sequence mass of a star and its white-dwarf remnant (the initial-final mass relation) is a powerful tool for exploration of mass loss processes during stellar evolution. We present an empirical…
Stellar rotation is a strong function of both mass and evolutionary state. Missions such as Kepler and CoRoT provide tens of thousands of rotation periods, drawn from stellar populations that contain objects at a range of masses, ages, and…
We perform evolutionary calculations of binary stars to find progenitors of systems with parameters similar to the recurrent nova U Sco. We show that a U Sco-type system may be formed starting with an initial binary system which has a…
The origin of the observed diversity of planetary system architectures is one of the main topic of the exoplanetary research. The detection of a statistically significant sample of planets around young stars allows us to study the early…
Infrared studies have revealed debris likely related to planet formation in orbit around ~30% of youthful, intermediate mass, main sequence stars. We present evidence, based on atmospheric pollution by various elements heavier than helium,…
We present new evidence for a problem with cooling rates predicted by substellar evolutionary models that implies model-derived masses in the literature for brown dwarfs and directly imaged planets may be too high. Based on our dynamical…
We review the current scenario of long-duration Gamma-ray burst (LGRB) progenitors, and in addition, present models of massive stars for a mass range of $10\text{--}150 \, \mathrm{M}_\odot$ with $\Delta \mathrm{M}=10 \, \mathrm{M}_\odot$…
We present the discovery of 5 millisecond pulsars found in the mid-Galactic latitude portion of the High Time Resolution Universe (HTRU) Survey. The pulsars have rotational periods from ~2.3 to ~7.5 ms, and all are in binary systems with…
We report discovery and characterization of a main-sequence G star orbiting a dark object with mass $1.90\pm 0.04 M_{\odot}$. The system was discovered via Gaia astrometry and has an orbital period of 731 days. We obtained multi-epoch RV…
We propose a possible binary evolution model for the formation of ultra-long period pulsars (ULPPs). The model involves two key stages: first, a neutron star (NS) in wide binaries undergoes an effective spin-down phase through wind-fed…
Observations made using TESS revealed a sample of low mass stars which show a periodic modulation on a period $<0.2$~d. Surprisingly many of these Ultra Fast Rotating (UFR) stars showed no evidence of flare activity which would be expected…
We report the discovery of companions to 5 nearby late M dwarfs (>M5), LHS1901, LHS4009, LHS6167, LP869-26 and WT460, and we confirm that the recently discovered mid-T brown dwarf companion to SCR1845-6357 is physically bound to that star.…
In an effort to determine accurate orbital and physical properties of a large number of bright stars, a method was developed to fit simultaneously stellar parameters (masses, luminosities, effective temperatures), distance, and orbits to…
We have derived masses and radii for both components in five short-period single-lined eclipsing binary stars discovered by the TrES wide-angle photometric survey for transiting planets. All these systems consist of a visible F-star primary…
We present the results of a radial velocity survey of 20 white dwarf plus M dwarf binaries selected as a follow up to a \textit{Hubble Space Telescope} study that aimed to spatially resolve suspected binaries. Our candidates are taken from…
We study the resolved stellar populations of dwarf galaxies in the nearby Centaurus A/M83 group of galaxies. Our goal is to characterize their evolutionary history and to investigate eventual similarities or differences with the dwarf…
We study the orbital evolution of wide binary stars in the solar neighborhood due to gravitational perturbations from passing stars. We include the effects of the Galactic tidal field and continue to follow the stars after they become…
This study presents observations of two possible substellar survivors of post-main sequence engulfment, currently orbiting white dwarf stars. Infrared and optical spectroscopy of GD 1400 reveal a 9.98 h orbital period, where the benchmark…
Metal pollution in white dwarf atmospheres is likely to be a signature of remnant planetary systems. Most explanations for this pollution predict a sharp decrease in the number of polluted systems with white dwarf cooling age. Observations…