相关论文: Imaging the secondary stars in cataclysmic variabl…
In this paper we study the impact of chemically evolved secondaries on CV evolution. We find that when evolved secondaries are included a spread in the secondary mass-orbital period plane comparable to that seen in the data is produced for…
The feasibility of using data from the NASA STEREO mission for variable star and asteroseismology studies has been examined. A data analysis pipeline has been developed that is able to apply selected algorithms to the entire database of…
We investigate the spectroscopic characteristics of the optical components of Be/X-ray binary systems, using data collected during our seven-year monitoring campaign. We find examples of major changes in the emission line profiles…
The total-to-selective extinction RV in the direction of a cluster is found to be 3.12 +/- 0.2 (close to its normal value). We derive the luminosity and mass functions for the cluster main sequence stars. The mass function slope is found to…
By proposing a statistic for the detection of secondary (Doppler) peaks in the CMBR power spectrum, the significance level at which such peaks may be detected are computed for a large range of model CMBR experiments. In particular, we…
We present a systematic survey for mass-transferring and recently-detached cataclysmic variables (CVs) with evolved secondaries, which are progenitors of extremely low-mass white dwarfs (ELM WDs), AM CVn systems, and detached ultracompact…
We report the first results from a new search for cataclysmic variables (CVs) using a combined X-ray (ROSAT) / infrared (2MASS) target selection that discriminates against background AGN. Identification spectra were obtained at the Isaac…
We critically examine the basic paradigm for the origin of the 2-3 hr period gap in cataclysmic variables (CVs). We carry out an extensive population synthesis study of CVs starting from ~ 3 x 10^6 primordial binaries, and evolving some ~ 2…
Several binary systems consisting of a massive star and a compact object have been detected above 100 GeV in the Galaxy. In most of these sources, gamma-rays show a modulation associated to the orbital motion, which means that the emitter…
Before binary components interact, they evolve as single stars do. We therefore first critically discuss massive single star processes which affect their evolution, stellar wind mass loss and rotation in particular. Next we consider binary…
The cosmic microwave background (CMB), the relic radiation from the early Universe, offers a unique window into both primordial conditions and the intervening large-scale structure (LSS) it traverses. Interactions between CMB photons and…
The Roche lobe formalism describes mass transfer from one star to another. We develop an extension to hierarchical triples, considering the case in which a star donates mass to a companion which is itself a binary. The L1 point moves as the…
Techniques are developed here for evaluating the r-modes of rotating neutron stars through second order in the angular velocity of the star. Second-order corrections to the frequencies and eigenfunctions for these modes are evaluated for…
We give an updated version of the analytical equation of state used in the Cambridge stellar evolution code (STARS) as a free to use open-source package that we have used to model cool white dwarfs down to temperatures…
Variations in the photometric parameters of stellar systems as a function of their evolution and the stellar populations comprising them are investigated. A set of seven evolutionary models with an exponential decrease in the star-formation…
Contact binaries (CBs) serve as fundamental laboratories for studying complex stellar interactions, including mass transfer, tidal effects, and angular momentum loss. In this work, we search for CB with high-precision light curves from the…
We carry out a photometric search for new cataclysmic variable stars (CVs), with the goal of identification for candidates of AR~Scorpii-type binary systems. We select GAIA sources that are likely associated with unidentified X-ray sources,…
We have taken K-band spectroscopy of a sample of 13 pre-CVs in order to examine them for anomalous chemical abundances. In particular, we study the strength of the 12CO and 13CO absorption bands that have been found diminished and enhanced,…
In this paper we present a spectroscopic study of six double-lined binaries, five of which were recently discovered in a high-resolution spectroscopic survey of optical counterparts of stellar X-ray sources. Thanks to high-resolution…
To measure the onset of mass transfer in eccentric binaries we have developed a two-phase SPH technique. Mass transfer is important in the evolution of close binaries, and a key issue is to determine the separation at which mass transfer…