The relevance of the standing accretion shock instability (SASI) compared to neutrino-driven convection in three-dimensional (3D) supernova-core environments is still highly controversial. Studying a 27M⊙ progenitor, we demonstrate, for the first time, that violent SASI activity can develop in 3D simulations with detailed neutrino transport despite the presence of convection. This result was ob...

During 3 consecutive nights, 13 southern Fand Gtype dwarfs and giants outside the conventional δ Scuti instability strip were observed at high spectral (3 km/s) and medium temporal (10-15 min) resolution. The stars were selected for their reported broad spectral lines (v sin i≥ 40 km/s) so that pulsation in higher azimuthal-order nonradial harmonics could, via the rotational Doppler effect, rev...

Stability properties are presented of dipole and quadrupole nonradial oscillation modes of model stars that experienced a late helium shell flash on their way to the white-dwarf cooling domain. The computed instability domains are compared with the observed hot variable central stars of planetary nebulae and the GW Vir pulsators.

In this paper we are interested in positive classical solutions of(1){−Δu=a(x)up−1 Ω,u>0 Ω,u=0 on ∂Ω, where Ω is a bounded annular domain (not necessarily an annulus) RN (N≥3) and a(x) nonnegative continuous function. We show the existence of solution for range supercritical values p when problem enjoys certain mild symmetry monotonicity conditions. As consequence our results, shall that (1) ha...

Received ; accepted – 2 – ABSTRACT Chandra and XMM-Newton X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4 minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations the white dwarf. This is the first detection of pulsations in a persistent supersoft source.