Related papers: Definitions of the Lambda Boo stars
We introduce the notion of star-symmetry for relations in a multi-pointed category and use it to obtain a characterization of the projective covers of 2-star-permutable categories. This generalizes the results of Rosick\'y-Vitale for…
We study solutions for boson stars in multiscalar theory. We start with simple models with N scalar theories. Our purpose is to study the models in which the mass matrix of scalars and the scalar couplings are given by an extended method of…
The release of the Hipparcos catalogue provides an opportunity to check results from asteroseismology. Here we show that Hipparcos parallaxes for two stars are in good agreement with oscillation results. For eta Boo, a probable detection of…
We present a new spectroscopic classification for OB stars based on H-band (1.5 micron to 1.8 micron) observations of a sample of stars with optical spectral types. Our initial sample of nine stars demonstrates that the combination of He I…
We translate O'Meara's classification Theorem 93:28 in terms of BONGs. BONGs, short for "basis of norm generators", are a new way of describing quadratic lattices, an alternative to the traditional Jordan decompositions. They were…
I briefly introduce a database of models that describe the evolution of star clusters in several broad-band photometric systems. Models are based on the latest Padova stellar evolutionary tracks - now including the alpha-enhanced case and…
The first two of a total of six nano-satellites that will constitute the BRITE-Constellation space photometry mission have recently been launched successfully. In preparation for this project, we carried out time-resolved colour photometry…
We currently know about 30 magnetars: seemingly isolated neutron stars whose properties can be (in part) comprehended only acknowledging that they are endowed with magnetic fields of complex morphology and exceptional intensity-at least in…
Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information one could obtain about the equation of state of matter at extremely high densities and because…
At present, there are several feasible observational probes of the first stars in the universe. Here, we examine the constraints on early stellar activity from the metallicity of the high-redshift Ly-$\alpha$ clouds, from the effects of…
The investigation of the orientation of galaxies is a standard test concerning to scenarios of galaxy formation, because different theories of galaxy formation make various predictions regarding to the angular momentum of galaxies. The new…
We discuss three different observational diagnostics related to disks around hot stars: absorption line determinations of rotational velocities of Be stars; polarization diagnostics of circumstellar disks; and X-ray line diagnostics of one…
Substantial progress has been achieved over the last decade in studies of stellar magnetism due to the improvement of magnetic field measurement methods. We review recent results on the magnetic field characteristics of early B- and O-type…
A neutron star was first detected as a pulsar in 1967. It is one of the most mysterious compact objects in the universe, with a radius of the order of 10 km and masses that can reach two solar masses. In fact, neutron stars are star…
We use moment method developed by Balona (1987) to identify the dominant mode of the multimode pulsating Delta Scuti star X Cae. It is shown as a l=1 and m=-1 non-radial mode gives a satisfactory fit of the amplitudes and phases of light…
The precise localization of short/hard (Type I) gamma-ray bursts (GRBs) in recent years has answered many questions but raised even more. I present some results of a systematic study of the optical afterglows of long/soft (Type II) and…
Tate objects have been studied by many authors. They allow us to deal with infinite dimensional spaces by identifying some more structure. In this article, we set up the theory of Tate objects in stable $(\infty,1)$-categories, while the…
We propose that stable boson stars generically fall within an infinite-parameter family of solutions that oscillate on any number of non-commensurate frequencies. We numerically construct two-frequency solutions and explore their parameter…
The presence of magnetic fields at the surfaces of many massive stars has been suspected for decades, to explain the observed properties and activity of OB stars. However, very few genuine high-mass stars had been identified as magnetic…
It is widely written and believed that Edwin Hubble introduced the terms `early' and `late types' to suggest an evolutionary sequence for galaxies. This is incorrect. Hubble took these terms from spectral classification of stars to signify…