Related papers: A new class of pulsating hot subdwarfs
With available Virtual Observatory tools, we looked for new bright blue high proper motion objects in the entire sky: white dwarfs, hot subdwarfs, runaway OB stars, and early-type stars in nearby young moving groups. We performed an all-sky…
We present five recycled pulsars discovered during a 21-cm survey of approximately 4,150 deg^2 between 15 deg and 30 deg from the galactic plane using the Parkes radio telescope. One new pulsar, PSR J1528-3146, has a 61 ms spin period and a…
We report the discovery of pulsations in the spectroscopic PG 1159 type pre-white dwarf SDSS J075415.12+085232.18. Analysis of the spectrum by Werner, Rauch and Kepler (2014) indicated Teff=120 000+/-10 000 K, log g=7.0+/-0.3, mass…
We report the discovery of rapid periodic signals in the light curves of two cataclysmic variables with prominent white-dwarf components in their spectra, SDSS J1457+51 and BW Sculptoris. These stars therefore appear to be new members of…
The long-term observations of the Galactic Centre as well as the Galactic anti-Centre regions in hard X-rays (10-300 keV) were made in experiments on board Prognoz-9 satellite and "Mir" orbital station (GRIF experiment). Some transient…
We discuss 76 large amplitude transients (Delta-m>1.5) occurring in the nuclei of galaxies, nearly all with no previously known Active Galactic Nucleus (AGN). They have been discovered as part of the Pan-STARRS1 (PS1) 3pi survey, by…
Global stellar oscillations probe the internal structure of stars. In low- to intermediate-mass red giants, these oscillations provide signatures from both the outer regions of the star as well as from the core. These signatures are…
PG 1605+072 has unique pulsational properties amongst the members of the new class of pulsating sdB (EC 14026) stars. It has the longest periods and the richest, most puzzling frequency spectrum (55 periods). We present a quantitative…
The group of lambda Bootis type stars comprises late B- to early F-type, Population I objects which are basically metal weak, in particular the Fe group elements, but with the clear exception of C, N, O and S. The present work is a…
We report the discovery of pulsations in three mixed-atmosphere, extremely low-mass white dwarf (ELM WD, M $\leqslant$ 0.3 M$_{\odot}$) precursors. Following the recent discoveries of pulsations in both ELM and pre-ELM WDs, we targeted…
We present the results of the first theoretical non-radial non-adiabatic pulsational study of M dwarf stellar models with masses in the range 0.1 to 0.5M_solar. We find the fundamental radial mode to be unstable due to an \epsilon mechanism…
The recent plethora of sky surveys, especially the Sloan Digital Sky Survey, have discovered many low-mass (M < 0.45 Msun) white dwarfs that should have cores made of nearly pure helium. These WDs come in two varieties; those with masses…
Helium core white dwarfs (WDs) with mass M <~ 0.20 Msun undergo several Gyrs of stable hydrogen burning as they evolve. We show that in a certain range of WD and hydrogen envelope masses, these WDs may exhibit g-mode pulsations similar to…
Over the past decade it has become apparent that a class of `bursting pulsars' exist with the discovery of PSR J1752+2359 and PSR J1938+2213. In these pulsars, a sharp increase in the emission is observed that then tends to systematically…
We present the discovery of a further five recycled pulsar systems in the mid-Galactic latitude portion of the High Time Resolution Universe (HTRU) Survey. The pulsars have rotational periods ranging from 2 ms to 66 ms, and four are in…
Stellar evolution calculations to the stage of the cooling white dwarf were done for population~I stars with masses on the main sequence $1M_\odot\le M_0\le 1.5M_\odot$. The final helium flash LTP is shown to occur in post--AGB stars with…
Rapidly evolving transients form a new class of transients which show shorter timescales of the light curves than those of typical core-collapse and thermonuclear supernovae. We performed a systematic search for rapidly evolving transients…
TIC033834484 and TIC309658435 are long-period pulsating subdwarf B star, which were observed extensively (675 and 621 days, respectively) by the Transiting Exoplanet Survey Satellite (TESS). The high-precision photometric light curve…
The detection of pulsations in white dwarfs with low mass offers the possibility of probing their internal structure through asteroseismology and place constraints on the binary evolutionary processes involved in their formation. In this…
We present a photometric and spectroscopic study of AzV322, an emission line object located in the Small Magellanic Cloud previously classified between O9 and B0. We analyze 17.5 years of $I$ and $V$ band OGLE-II, III and IV light curves…