相关论文: Abnormal lithium abundance in several Ap-Bp stars

The rapidly oscillating Ap stars are of importance for studying the atmospheric structure of stars where the process of chemical element diffusion is significant. We have performed a survey for rapid oscillations in a sample of 9 luminous…

Ap/Bp stars are magnetic chemically peculiar early A and late B type stars of the main sequence. They exhibit peculiar surface abundance anomalies that are thought to be the result of gravitational settling and radiative levitation. The…

The stellar evolution of lithium-rich (Li-rich) giant stars at very low metallicities remains largely unexplored to date. Using two recent large LAMOST catalogues of field, low-mass giant stars (both Li-rich and Li-poor) with metallicities…

Lithium is a fragile but crucial chemical element in the universe, exhibits interesting and complex behaviors. Thanks to the massive spectroscopic data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)…

We present a multi-instrument analysis of the rapidly oscillating Ap (roAp) star HD 42659. We have obtained $B$ photometric data for this star and use these data, in conjunction with TESS observations, to analyse the high-frequency…

The upper main sequence magnetic chemically peculiar (Ap) stars exhibit a non-uniform distribution of chemical elements across their surfaces and with height in their atmospheres. These inhomogeneities, responsible for the conspicuous…

Since its discovery more than half a century ago Przybylski's star (HD101065) continues to excite the astronomical community by the unusual nature of its spectrum, exhibiting exotic element abundances. This star was also the first magnetic…

Context: Stars with about 1$-$2 solar masses at the red giant branch (RGB) represent an intriguing period of stellar evolution, i.e. when the convective envelope interacts with the fast-rotating core. During these mixing episodes freshly…

We have investigated the abundance anomalies of lithium for stars with planets in the temperature range of 5600--5900 K reported by Israelian and coworkers, as compared to 20 normal stars at the same temperature and metallicity ranges. Our…

Intermediate-mass, magnetic chemically peculiar (Ap) stars provide a unique opportunity to study the topology of stellar magnetic fields in detail and to investigate magnetically driven processes of spot formation. Here we aim to derive the…

Rapidly oscillating Ap (roAp) stars have rarely been found in binary or higher order multiple systems. This might have implications for their origin. We intend to study the multiplicity of this type of chemically peculiar stars, looking for…

To address the puzzling photometric properties of horizontal branch stars in Galactic GCs, several different groups have undertaken detailed spectroscopic analyses of individual blue HB stars. Hotter BHB stars show strong metal enhancement…

Intermediate-mass, chemically peculiar stars with strong magnetic fields give us an excellent opportunity to study the topology of their surface magnetic fields and the interplay between magnetic geometries and abundance inhomogeneities in…

Precise Li abundances are determined for 54 giant stars mostly evolving across the Hertzsprung gap. We combine these data with rotational velocity and with information related to the deepening of the convective zone of the stars to analyse…

The light variability of hot magnetic chemically peculiar stars is typically caused by the flux redistribution in spots with peculiar abundance. This raises the question why some stars with surface abundance spots show significant…

Analysis of high-resolution spectropolarimetric observations of early-type magnetic stars is currently the most advanced method of obtaining detailed information on their surface magnetic field topologies and horizontal spot distributions.…

How magnetic fields contribute to the differentiation of the rotation rates of the Ap stars and affect the occurrence of non-radial pulsation in some of them are important open questions. Valuable insight can be gained into these questions…

We present the results of a systematic study of the magnetic fields and other properties of the Ap stars with resolved magnetically split lines. This study is based on new measurements of the mean magnetic field modulus, the mean…

The early-type chemically peculiar stars often show strong magnetic fields on their surfaces. These magnetic topologies are organized on large scales and are believed to be close to an oblique dipole for most of the stars. In a striking…

We report on the determination of the lithium abundance [A(Li)] of 52 solar-like stars. For 41 objects the A(Li) here presented corresponds to the first measurement. We have measured the equivalent widths of the 6708\AA\ lithium feature in…