相关论文: Study of sdO models. Pulsation Analysis

Time-dependent meridional circulation and differential rotation in radiative zones are central open issues in stellar evolution theory. We streamline this challenging problem using the downward control principle of atmospheric science,…

Recently, measurements of abundances in extremely metal poor (EMP) stars have brought new constraints on stellar evolution models. In an attempt to explain the origin of the abundances observed, we computed pre--supernova evolution models,…

On the Hertzsprung-Russell diagram, F-type solar pulsators connect the Sun to intermediate mass stars located on the instability strip. With respect to lower mass stars, they are structurally peculiar in the sense that they are constituted…

Circumstellar environments of oxygen-rich stars are among the strongest SiO maser emitters. Physical processes such as collisions, infrared pumping and overlaps favors the inversion of level population and produce maser emission at…

Excitation of radial oscillations in population I (X=0.7, Z=0.02) red supergiants is investigated using the solution of the equations of radiation hydrodynamics and turbulent convection. The core helium burning stars with masses 8M_odot <=…

For the first time nonradial oscillations of superfluid nonrotating stars are self-consistently studied at finite stellar temperatures. We apply a realistic equation of state and realistic density dependent model of critical temperature of…

Radiative opacity is an important quantity in the modeling of stellar structure and evolution. In the present work we recall the role of opacity in the interpretation of pulsations of different kinds of stars. The detailed opacity code…

L19-2 is a DAV star, which has been intermittently observed from 1976 to 2013. Five independent pulsation modes of 350\,s, 192\,s, 143\,s, 118\,s, and 113\,s are identified. The five modes can be used to constrain the fitting models. The…

An isolated pulsar is a rotating neutron star possessing a high magnetic dipole moment that generally makes a finite angle with its rotation axis. As a consequence, the emission of magnetic dipole radiation (MDR) continuously takes away its…

Quasi-periodic oscillations have been seen in the light curves following several magnetar giant flares. These oscillations are of great interest as they probably provide our first ever view of the normal modes of oscillation of neutron…

The cores of compact stars reach the highest densities in nature and therefore could consist of novel phases of matter. We demonstrate via a detailed analysis of pulsar evolution that precise pulsar timing data can constrain the star's…

The metal-insulator and spin state transitions of CoO under high pressure are studied by using density functional theory combined with dynamical mean-field theory. Our calculations predict that the metal-insulator transition in CoO is a…

Among A-type main-sequence variables, pulsations of $\delta$ Sct and $\gamma$ Dor variables are driven in the He II ionization zone, while H-ionization zone and strong magnetic fields seem to play roles in the excitation of high-order…

The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with…

We are reaching relative maturity and standardization in one-dimensional single-star stellar evolution and pulsation modeling, and are making advances in binary and 2D and 3D models. However, many physical inputs are still uncertain or…

The advent of massively parallel supercomputing has begun to permit explicit 3--D simulations of turbulent convection occurring within the cores of early-type main sequence stars. Such studies should complement the stellar structure and…

In order to investigate the possible influence of rotation on the efficiency of the first dredge-up we determined atmospheric parameters, masses, and abundances of carbon, nitrogen, and oxygen in a sample of evolved intermediate mass stars.…

We report spectroscopic observations for 19 $\delta$\,Sct candidates observed by the {\it Kepler} satellite both in long and short cadence mode. For all these stars, by using spectral synthesis, we derive the effective temperature, the…

Carbon and oxygen are key tracers of the Galactic chemical evolution; in particular, a reported upturn in [C/O] towards decreasing [O/H] in metal-poor halo stars could be a signature of nucleosynthesis by massive Population III stars. We…

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…