相关论文: Ap stars with variable periods

Our paper presents new methods for finding and testing of weak periodic variability of stellar objects developed for the purpose of detecting expected regular light variations of magnetic chemically peculiar (mCP) candidates in the Large…

The recent variability survey of the NGC 3766 cluster revealed a considerable number of periodic variable stars in a region of the H-R diagram where no pulsation is expected. This region lies between the instability strips of the delta…

Contrary to young neutron stars, young strange stars are not subject to the r-mode instability which slows rapidly rotating, hot neutron stars to rotation periods near 10 ms via gravitational wave emission. Young millisecond pulsars are…

In order to extend our previous studies of the unexplained phenomenon of cyclic amplitude variations in pulsating red giants, we have used the AAVSO time-series analysis package VSTAR to analyze long-term AAVSO visual observations of 50…

We present a new analysis of the long-period variables in the Large Magellanic Cloud (LMC) from the MACHO Variable Star Catalog. Three-quarters of our sample of evolved, variable stars have periodic light curves. We characterize the stars…

The discovery of exotic abundances, chemical inhomogeneities, and weak magnetic fields on the surface of late B-type primaries in spectroscopic binaries has important implications not only for our understanding of the formation mechanisms…

Various surveys focusing on the magnetic properties of intermediate-mass main sequence (MS) stars have been previously carried out. One particularly puzzling outcome of these surveys is the identification of a dichotomy between the strong…

In this paper we present radial velocity curves of AGB variables that exhibit various kinds of anomalies: Semiregular variables (SRVs) with typical mira periods, SRVs exceeding the mira 2.5 mag amplitude limit, miras with secondary maxima…

CU Vir has been the first main sequence star that showed regular radio pulses that persist for decades, resembling the radio lighthouse of pulsars and interpreted as auroral radio emission similar to that found in planets. The star belongs…

The chemically peculiar (CP) stars of the upper main sequence are well suited for investigating the impact of magnetic fields and diffusion on the surface layers of slowly rotating stars. They can even be traced in the Magellanic Clouds and…

Rotation periods inferred from the magnetic variability of some Ap stars are incredibly long, exceeding ten years in some cases. An explanation for such slow rotation is lacking. This paper attempts to provide an explanation of the…

We report rotation periods, variability characteristics, gyrochronological ages for ~950 of the Kepler Object of Interest host stars. We find a wide dispersion in the amplitude of the photometric variability as a function of rotation,…

Short period binary systems containing magnetic Ap stars are anomalously rare. This apparent anomaly may provide insight into the origin of the magnetic fields in theses stars. As an early investigation of this, we observed three close…

KQ Vel is a peculiar A0p star with a strong surface magnetic field of about 7.5 kG. It has a slow rotational period of nearly 8 years. Bailey et al. (2015) detected a binary companion of uncertain nature, and suggested it could be a neutron…

We simulate the light variability of the Ap star epsUMa using the observed surface distributions of Fe, Cr, Ca, Mn, Mg, Sr and Ti obtained with the help of Doppler Imaging technique. Using all photometric data available we specified light…

Our recent studies of late B-type stars with HgMn peculiarity revealed for the first time the presence of fast dynamical evolution of chemical spots on their surfaces. These observations suggest a hitherto unknown physical process operating…

We have discovered a new rapidly oscillating Ap star among the Kepler Mission target stars, KIC 10195926. This star shows two pulsation modes with periods that are amongst the longest known for roAp stars at 17.1 min and 18.1 min,…

Magnetic perturbations to the frequencies of low degree, high radial order, axisymmetric pulsations in stellar models permeated by large scale magnetic fields are presented. Magnetic fields with dipolar, quadrupolar and a superposition of…

The classical nova CP Puppis has been observed to have particularly puzzling and peculiar properties. In particular, this classical nova displays occasional bursts in its long-term ASAS-SN light curve. Here we report on 5 sectors of TESS…

The chemically peculiar (CP) stars of the upper main sequence are excellent astrophysical laboratories for investigating the diffusion, mass loss, rotational mixing, and pulsation in the presence and absence of a stable local magnetic…