A5008769660- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Scientific Measurement and Uncertainty Evaluation
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- SAS software applications and methods
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
University of Sheffield
2014-2019
We present high precision, model independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries combine these with previously published data to test the theoretical dwarf mass-radius relationship. reach a mean precision of 2.4 per cent 2.7 radius, our best reaching 0.3 0.5 radius. find excellent agreement between measured predicted radii across wide range masses temperatures. also all less than 0.48M$_\odot$ be fully consistent helium core models, but they are...
We present measurements of the component masses in 15 Cataclysmic Variables (CVs) – 6 new estimates and 9 improved estimates. provide calibrations relationship between superhump period excess mass ratio, use this relation to estimate donor star for 225 superhumping CVs. With an increased sample we revisit implications CV evolution. confirm high white dwarfs CVs, but find no trend dwarf with orbital period. argue a revision location minimum CVs 79.6 ± 0.2 min, significantly shorter than...
We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations their orbital periods. Our includes 67 binaries, both detached and semi-detached with M-dwarfs, K-dwarfs, brown or secondaries. In total, we have observed more than 650 dwarf eclipses. use this sample search period aim identify underlying cause these variations. find that probability observing increases significantly observational baseline. particular, all...
We present high time resolution SDSS-$g'$ and SDSS-$z'$ light curves of the primary eclipse in SDSS J141126.20+200911.1, together with time-resolved X-Shooter spectroscopy near-infrared $JHK_{s}$ photometry. Our observations confirm substellar nature companion, making J141126.20+200911.1 first eclipsing white dwarf/brown dwarf binary known. measure a (white model dependent) mass radius for brown companion $M_{2} = 0.050 \pm 0.002$ $M_{\odot}$ $R_{2} 0.072 0.004$ $M_{\odot}$, respectively....
We present new time-resolved photometry of 74 cataclysmic variables (CVs), 47 which are eclipsing. Thirteen these eclipsing systems newly discovered. For all systems, we show high cadence (1–20 s) light curves obtained with the high-speed cameras ULTRACAM and ULTRASPEC. provide or refined ephemerides, supply mid-eclipse times for observed eclipses. assess potential light-curve modelling to determine their system parameters, finding 20 that appear be suitable future study. Systems particular...
We present high-speed, multicolour photometry of the faint, eclipsing cataclysmic variable (CV) SDSS J105754.25+275947.5. The light from this system is dominated by white dwarf. Nonetheless, averaging many eclipses reveals additional features eclipse bright spot. This enables fitting a parameterised model to these average curves, allowing precise measurement parameters. find mass ratio q = 0.0546 $\pm$ 0.0020 and inclination i 85.74 0.21$^{\circ}$. dwarf donor masses were found be...
The majority of cataclysmic variable (CV) stars contain a stochastic noise component in their light curves, commonly referred to as flickering. This can significantly affect the morphology CV eclipses and increases difficulty obtaining accurate system parameters with reliable errors through eclipse modelling. Here we introduce new approach modelling, which models flickering help Gaussian processes (GPs). A parameterised model - an additional GP is simultaneously fit 8 dwarf nova ASASSN-14ag...
We present high-speed, three-colour photometry of the eclipsing dwarf nova PHL 1445, which, with an orbital period 76.3 min, lies just below minimum ∼82 min for cataclysmic variable stars (CVs). Averaging four eclipses reveals resolved white and bright spot. determined system parameters by fitting a parametrized eclipse model to averaged light curve. obtain mass ratio q = 0.087 ± 0.006 inclination i 85|$_{.}^{\circ}$|2 0|$_{.}^{\circ}$|9. The primary donor masses were found be Mw 0.73 0.03...