Related papers: On the evolutionary status of short period catacly…
The standard picture of CV secular evolution predicts a spike in the CV distribution near the observed short-period cutoff P_0 ~ 78 min, which is not observed. We show that an intrinsic spread in minimum (`bounce') periods P_b resulting…
A recent development in the study of magnetic cataclysmic variable stars (mCVs) has been the identification of asynchronously spinning mCVs with orbital periods <2 h that have significantly higher white dwarf spin-to-orbital period ratios…
The present-day formation of cataclysmic variables (CVs) with brown dwarf (BD) secondaries (0.013 M_sun < M_sec < 0.075 M_sun) is investigated using a population synthesis technique. Results from the latest, detailed models for BDs have…
We calculate the stellar evolution of both white dwarfs (WDs) in AM CVn binaries with orbital periods of $P_{\mathrm{orb}} \approx 5-70$ minutes. We focus on the cases where the donor starts as a $M_{\mathrm{He}} < 0.2 \, M_{\odot}$ Helium…
A long standing and unverified prediction of binary star evolution theory is the existence of a population of white dwarfs accreting from sub-stellar donor stars. Such systems ought to be common, but the difficulty of finding them, combined…
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 present the results of spectroscopic observations of two eclipsing WR+OB-type systems - CQ Cep and CX Cep, performed in 2020-2023 with a low-resolution slit spectrograph TDS ($\lambda\lambda= 3660-7410$\AA, $R = 1300-2500$) on 2.5-m…
We report the discovery and analysis of 36 new eclipsing EL CVn-type binaries, consisting of a core helium-composition pre-white dwarf and an early-type main-sequence companion, more than doubling the known population of these systems. We…
The orbital periods of most eclipsing cataclysmic binaries are not undergoing linear secular decreases of order a few parts per billion as expected from simple theory. Instead, they show several parts per million increases and decreases on…
We show that the secondaries in short-period cataclysmic variables with orbital periods $P < 3$ hr are close to the solar-abundance main sequence defined by single field stars. In cataclysmic variables with $P > 3$ hr, the earliest spectral…
As part of a project to better characterize comparatively bright, yet little studied cataclysmic variables time resolved photometry of the three eclipsing novalike variables EC 21178-5417, GS Pav und V345 Pav is presented. Previously known…
We consider evolutionary models for the population of short-period (<10 hr) low-mass black-hole binaries (LMBHBs) and compare them with observations of soft X-ray transients (SXTs). We show that assuming strongly reduced magnetic braking…
We present a sample of 30 well observed Post Common Envelope Binaries (PCEBs). Deriving the cooling age of the white dwarfs, we show that the PCEB population is dominated by young systems. Having calculated the orbital evolution of the…
The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period…
We present the results of our study of ASASSN-14dx, a previously known but poorly characterised cataclysmic variable (CV). The source was observed as part of an ongoing high-time-resolution photometric survey of CVs, which revealed that, in…
The orbital evolution of cataclysmic variables in which the companion is illuminated by a fraction of the accretion luminosity consists of irradiation-driven limit cycles on thermal timescales, superimposed on a secular evolution toward…
We report the discovery of eclipses and the first orbital period measurements for four cataclysmic variables, plus the first orbital period measurements for one known eclipsing and two magnetic systems. SDSS J093537.46+161950.8 exhibits…
Circumbinary planets and brown dwarfs form in complex gravitational environments, offering insights into formation, orbital stability, and habitability prospects. However, they remain underrepresented, with only 60 confirmed or candidate…
The spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been determined from a carefully established sample of 459 CVs. The sample contains all of the CVs…
We present LAMOST J0140355+392651 (hereafter J0140), a close ($P_{\rm orb} = 3.81$ hours) binary containing a bloated, low-mass ($M \approx 0.15 M_{\odot}$) proto-white dwarf (WD) and a massive ($M\approx 0.95\,M_{\odot}$) WD companion. The…