相关论文: Mixing in two magnetic OB stars discovered by the …

About ten percent of all OB stars show strong, large-scale surface magnetic fields. The interaction of the magnetic field and the wind is believed to be the cause for the X-ray emission shown by these objects. We therefore run numerical…

Photospheric abundances of C, N, O, and Na were determined by applying the synthetic spectrum-fitting technique to 34 snap-shot high-dispersion spectra of 22 RR Lyr stars covering a metallicity range of -1.8 <[Fe/H] < 0.0, with an aim of…

Recent maser surveys have shown that many potential OH/IR stars have no OH masers in their circumstellar envelopes, despite the modest requirements which should be implicitly met by IRAS colour-selected candidates. It has been suggested…

We investigate energy release in the interacting magnetospheres of binary neutron stars (BNSs) with global 3D force-free electrodynamics simulations. The system dynamics depend on the inclinations $\chi_1$ and $\chi_2$ of the stars'…

Absolute and differential chemical abundances are presented for the largest group of massive stars in M31 studied to date. These results were derived from intermediate resolution spectra of seven B-type supergiants, lying within four OB…

Observations of double-lined spectroscopic eclipsing binaries are ideal to study stellar evolution. They have tight model-independent constraints on their masses and radii. With the addition of spectroscopically determined effective…

Recently discovered massive $\alpha$-enriched (MAE) stars have surface chemistry consistent with members of the older thick disk Milky Way population but high masses ($\sim$ 1.5 - 3 M$_{\odot}$) that suggest these stars are young. The…

We present a systematic numerical relativity study of the mass ejection and the associated electromagnetic transients and nucleosynthesis from binary neutron star (NS) mergers. We find that a few $10^{-3}\, M_\odot$ of material are ejected…

We report the detection of a magnetic field in the helium-strong star CPD-57 3509 (B2 IV), a member of the Galactic open cluster NGC3293, and characterise the star's atmospheric and fundamental parameters. Spectropolarimetric observations…

The nitrogen to carbon (N/C) and nitrogen to oxygen (N/O) ratios are the most sensitive quantities to mixing in stellar interiors of intermediate and massive stars. We further investigate the theoretical properties of these ratios as well…

Massive stars are predominantly found in binaries and higher order multiples. While the period and eccentricity distributions of OB stars are now well established across different metallicity regimes, the determination of mass-ratios has…

Inspiraling and merging binary neutron stars (BNSs) are important sources of both gravitational waves and coincident electromagnetic counterparts. If the BNS total mass is larger than a threshold value, a black hole ensues promptly after…

Stellar rotation produces an internal mixing of the elements due to shear instability and meridional circulation. This leads to observable $N/C$ enhancements in massive stars above about 7--9 $M_{\odot}$. Rotation also favours mass loss by…

Isomerism in complex organic molecules provides key insights into the formation mechanisms and physical conditions of the interstellar medium (ISM). Among the C$_2$H$_5$NO isomers, only acetamide and trans-N-methylformamide (trans-NMF) have…

Massive stars are inherently extreme objects, in terms of radiation, mass loss, rotation, and sometimes also magnetic fields. Concentrating on a (personally biased) subset of processes related to pulsations, rapid rotation and its interplay…

We present a state-of-the-art analysis technique able to simultaneously reproduce the entire H and He spectra of OB-type stars in the visual and the near-IR and to derive highly accurate metal abundances (so far C and N). The spectrum…

Various types of magnetic fields occur in stars: small scale fields, large scale fields, and internal toroidal fields. While the latter may be ubiquitous in stars due to differential rotation, small scale fields (spots) may be associated…

Stars of spectral types O and B produce neutron stars (NSs) after supernova explosions. Most of NSs are strongly magnetised including normal radio pulsars with $B \propto 10^{12}$ G and magnetars with $B\propto 10^{14}$ G. A fraction of…

An analysis of the CN and CH band strengths measured in a large sample of M71 and M13 main sequence stars by Cohen (1999a,b) is undertaken using synthetic spectra to quantify the underlying C and N abundances. In the case of M71 it is found…

The increase in the sensitivity of gravitational wave interferometers will bring additional detections of binary black hole and double neutron star mergers. It will also very likely add many merger events of black hole - neutron star…