Related papers: Post nova white dwarf cooling in V1500 Cygni
By comparing two age indicators of high-mass white dwarfs derived from Gaia data, two discoveries have been made recently: one is the existence of a cooling anomaly that produces the Q branch structure on the Hertzsprung--Russell diagram,…
Fluctuations during a prolonged maximum have been observed in several nova eruptions, although it is not clear, and can not be deduced directly from observations, if the phenomenon is an actual physical reaction to some mechanism…
We present an analysis of X-ray and ultra-violet data of the dwarf nova VW Hyi that were obtained with XMM-Newton during the quiescent state. The X-ray spectrum indicates the presence of an optically thin plasma in the boundary layer that…
The evolution of white dwarfs (WDs) depends crucially on thermal processes. The plasma in their core can produce neutrinos which escape from the star, thus contributing to the energy loss. While in absence of a magnetic field the main…
We present a set of full evolutionary sequences for white dwarfs with hydrogen-deficient atmospheres. We take into account the evolutionary history of the progenitor stars, all the relevant energy sources involved in the cooling, element…
Archival X-ray observations of EF Eridani obtained in a low state revealed distinct X-ray detections at a luminosity L_X ~ 2 10^{29} erg/s, three orders of magnitude below its high state value. The plasma temperature was found to be as low…
We present a model for the structure, temporal behavior, and evolutionary status of the bipolar nebula M2-9. According to this model the system consists of an AGB or post-AGB star and a hot white dwarf companion, with an orbital period of…
Three brown dwarfs in different evolutionary stages have been observed with the Chandra X-ray Observatory. Combining the new observations with previous studies presented in the literature yields a brown dwarf sample that reaches well down…
We present the results of our spectroscopic study of the dwarf nova SS Cygni, using Roche tomography to map the stellar surface and derive the system parameters. Given that this technique takes into account the inhomogeneous brightness…
We present the results of a study to discover prospective new white dwarf-L dwarf binaries as identified by their near-infrared excesses in the UKIDSS catalogue. We obtained optical spectra to validate the white dwarf nature for 22 of the…
As dense and hot bodies with a well-understood equation of state, white dwarfs offer a unique opportunity to investigate new physics. In this paper, we examine the role of dark sectors, which are extensions of the Standard Model of particle…
The atmospheres of brown dwarfs orbiting in close proximity to their parent white dwarf represent some of the most extreme irradiated environments known. Understanding their complex dynamical mechanisms pushes the limits of theoretical and…
A deep imaging survey covering the entire $23\arcmin$ diameter of the old open cluster M67 to $V = 25$ has been carried out using the mosaic imager (UHCam) on the Canada-France-Hawaii Telescope. The cluster color-magnitude diagram (CMD) can…
The evolution of white dwarfs is a simple gravothermal process. This means that their luminosity function, i.e. the number of white dwarfs per unit bolometric magnitude and unit volume as a function of bolometric magnitude, is a…
If cooled-down neutron stars have a thin atomic crystalline-iron crust, they must diffract X-rays of appropriate wavelength. If the diffracted beam is to be visible from Earth, the illuminating source must be very intense and near the…
White dwarf evolution is essentially a gravothermal cooling process, which,for cool white dwarfs, sensitively depends on the treatment of the outer boundary conditions. We provide detailed outer boundary conditions appropriate for computing…
The far-infrared [C II] 158 micrometer fine structure transition is considered to be a dominant coolant in the interstellar medium. For this reason, under the assumption of a thermal steady state, it may be used to infer the heating rate…
We present spectrophotometry of the eclipsing old nova BT Mon (Nova Mon 1939). By detecting weak absorption features from the secondary star, we find its radial velocity semi-amplitude to be K_R = 205+/-5 km/s and its rotational velocity to…
NGC 6791 is a well-studied, metal-rich open cluster that is so close to us that can be imaged down to luminosities fainter than that of the termination of its white dwarf cooling sequence, thus allowing for an in-depth study of its white…
We report identification of the optical counterpart to the companion of the millisecond pulsar J2317+1439. At the timing position of the pulsar, we find an object with $g=22.96\pm0.05$, $r=22.86\pm0.04$ and $i=22.82\pm0.05$. The magnitudes…