Related papers: The lambda Bootis stars
Type II Cepheids are a class of pulsating variable stars that play a critical role in our understanding of stellar evolution, distance measurement and tracing the structure and kinematics of old stars in nearby galaxies. This review…
Neutron stars have long been regarded as extra-terrestrial laboratories from which we can learn about extreme energy density matter at low temperatures. In this article, I highlight some of the recent advances made in astrophysical…
We investigate the stability of stars with a density discontinuity between a high-density core and a very low density mantle. Previous work on "strange dwarfs" suggested that such a discontinuity could stabilize stars that would have been…
In nature there are various pairs of observed phenomena and observing scientific techniques which are elegantly coupled with each other. A very general and well known example is the fact that the metal we use to build telescopes were once…
Top physics provides a fertile ground for new-physics searches. At present, most top observables appear to be in good agreement with the respective Standard Model predictions. However, in the case of decay modes that are suppressed in the…
The evidence for the dark matter of the hot big bang cosmology is about as good as it gets in natural science. The exploration of its nature is now led by direct and indirect detection experiments, to be complemented by advances in the full…
n this article, firstly, we introduce the notion of star modules with respect to a balanced pair and obtain some properties. We mainly give the relationship between n-X star modules and n-X tilting modules [9], and a new characterization of…
Young stars on their way to the ZAMS evolve in significantly different ways depending on mass. While the theoretical and observational properties of low- and intermediate-mass stars are rather well understood and/or empirically tested, the…
Massive stars like company. Here, we provide a brief overview of progresses made over the last 5 years by a number of medium and large surveys. These results provide new insights on the observed and intrinsic multiplicity properties of main…
Investigating chemically peculiar pulsating stars is crucial for understanding the pulsation driving mechanism in detail. To reveal the true peculiarity properties of stars detailed spectroscopic analysis is essential. Therefore, in this…
The discoveries of anomalous compact objects challenge our understanding of the standard theory of stellar structures and evolution. They serve as an excellent laboratory to search for new physics. Earlier studies on spherically symmetric…
We review our knowledge of the mixing properties of magnetic OB stars and discuss whether the observational data presently available support, as predicted by some theoretical models, the idea that magnetic phenomena favour the transport of…
Compact relativistic stars allow us to study the nature of matter under extreme conditions, probing regions of parameter space that are otherwise inaccessible. Nuclear theory in this regime is not well constrained: one key issue is whether…
In spite of the almost all-encompassing variability of Be stars, surveys play a steadily increasing role in complementing the insights gained from single-star studies. The definition of classical Be stars as recently augmented by…
We present Washington photometry of a field central to the Bootes I dwarf spheroidal galaxy, which was discovered as a stellar overdensity in the Sloan Digital Sky Survey (DR5). We show that the Washington filters are much more effective…
Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, $\Lambda$CDM. This is motivated by a range of apparently serious theoretical issues, involving…
Symbiotic stars, interacting binaries composed of a cool giant and a hot compact companion, exhibit complex variability across the electromagnetic spectrum. Over the past decades, large-scale photometric and spectroscopic surveys from…
Witten's conjecture about strange quark matter (`Strange Matter') being the ground state of QCD at finite baryon number is presented and stars made of strange matter (`Strange Stars') are compared to neutron stars. The only observable way…
Magnetic chemically peculiar (mCP) stars of the upper part of the main sequence usually exhibit strictly periodic variations of their light, spectrum and magnetic field. These changes can be well explained using the oblique rotator model of…
The study of the long-dead early generations of massive stars is crucial in order to obtain a complete picture of the chemical evolution of the Universe, hence the origin of the elements. The nature of these stars can be inferred indirectly…