# Exotic Stars as Challenges to Evolution: an Evaluation

@inproceedings{Jeffery2002ExoticSA,
title={Exotic Stars as Challenges to Evolution: an Evaluation},
author={C. Simon Jeffery},
year={2002}
}
Magnetic and pulsational variability of Przybylski’s star (HD 101065)
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
Circumstellar discs in X / γ-ray binaries : first results from the Echelle spectrograph
• 2016
Here we report our first spectral observations of Be/X-ray and γ-ray binaries obtained with the new Echelle spectrograph of the National Astronomical Observatory Rozhen. For four objects (LSI+61303,
A radial velocity survey for post-common-envelope Wolf–Rayet central stars of planetary nebulae: first results and discovery of the close binary nucleus of NGC 5189
• Physics
• 2015
The formation of Wolf-Rayet central stars of planetary nebulae ([WR] CSPNe) whose spectroscopic appearance mimics massive WR stars remains poorly understood. Least understood is the nature and
Circumstellar discs in X/gamma-ray binaries: first results from the Echelle spectrograph
• Physics
• 2015
Here we report our first spectral observations of Be/X-ray and gamma-ray binaries obtained with the new Echelle spectrograph of the National Astronomical Observatory Rozhen. For four objects
First detections of FS Canis Majoris stars in clusters. Evolutionary state as constrained by coeval massive stars
• Physics
• 2014
FS CMa stars are low-luminosity objects showing the B[e] phenomenon whose evolutionary state remains a puzzle. These stars are surrounded by compact disks of warm dust of unknown origin. Hitherto,
Rotational and Cyclical Variability in γ Cas
γ Cas is an unusual classical Be star for which the optical-band and hard X-ray fluxes vary on a variety of timescales. We report results of a nine-year monitoring effort on this star with a robotic
Metal abundances in PG1159 stars from Chandra and FUSE spectroscopy
• Physics
• 2002
We investigate FUSE spectra of three PG1159 stars and do not find any evidence for iron lines. From a comparison with NLTE models we conclude a deficiency of 1-1.5 dex. We speculate that iron was
Short-term variability and mass loss in Be stars
Context. Be stars are physically complex systems that continue to challenge theory to understand their rapid rotation, complex variability and decretion disks. $\gamma$ Cassiopeiae ($\gamma$ Cas) is
Short-term variability and mass loss in Be stars – VI. Frequency groups in γ Cas detected by TESS
In photometry of γ Cas (B0.5 IVe) from the Solar Mass Ejection Imager (SMEI) and the BRIght Target Explorer (BRITE)-Constellation satellites, indications of low-order non-radial pulsation have
Critical study of the distribution of rotational velocities of Be stars - II: Differential rotation and some hidden effects interfering with the interpretation of the V sin i parameter
Aims. We assume that stars may undergo surface differential rotation to study its impact on the interpretation of V sin i and on the observed distribution Φ ( u ) of ratios of true rotational