Related papers: Stability boundaries for massive stars in the sHR …
The content of gas in galaxies with an anomalously high relative mass of hydrogen $M_{HI}/M_*$ for a given mass of the stellar population $M_*$ (VHR-galaxies) is considered, using the available samples of such galaxies. It is shown that,…
We revisit the stability of very massive nonrotating main-sequence stars at solar metallicity, with the goal of understanding whether radial pulsations set a physical upper limit to stellar mass. Models of up to 938 solar masses are…
Using a reduced proper motion discriminator, I obtain a sample of 4588 subdwarfs from the Revised NLTT Catalog of Salim & Gould. The ample statistics and low contamination permit much more precise determinations of halo parameters than has…
We investigate the pulsational properties of RSG models --- which we evolve from ZAMS masses in the range 10 to $20 \Msun$ --- by means of linear and non-linear calculations. We find period and growth rate of the dominant fundamental mode…
I review recent progress on understanding eruptions of unstable massive stars, with particular attention to the diversity of observed behavior in extragalatic optical transient sources that are generally associated with giant eruptions of…
Yellow and red supergiants are evolved massive stars whose numbers and locations on the HR diagram can provide a stringent test for models of massive star evolution. Previous studies have found large discrepancies between the relative…
We study the system constructed by charged scalar fields linearly coupled to asymptotically flat horizonless compact reflecting stars. We obtain bounds on the charge of the scalar field, below which the scalar hairy star is expected to…
Despite major progress in our understanding of massive stars, concerning discrepancies still remain between observations and theory. Most notable are the numerous stars observed beyond the theoretical main sequence, an evolutionary phase…
A (charged) rotating black hole may be unstable against a (charged) massive scalar field perturbation due to the existence of superradiance modes. The stability property depends on the parameters of the system. In this paper, the…
We review the orbital stability of the planar circular restricted three-body problem, in the case of massless particles initially located between both massive bodies. We present new estimates of the resonance overlap criterion and the Hill…
The overstability of the fundamental radial mode in M dwarf models was theoretically predicted by Rodr\'iguez-L\'opez et al. (2012). The periods were found to be in the ranges ~25-40 min and ~4-8 h, depending on stellar age and excitation…
We conduct a systematic survey of the regions in which distant satellites can orbit stably around the four giant planets in the solar system, using orbital integrations of up to $10^9$ yr. In contrast to previous investigations, we use a…
$\delta$ Scuti stars are remarkable objects for asteroseismology. In spite of decades of investigations, there are still important questions about these pulsating stars to be answered, such as their positions in $\log$$T_{\rm eff}$ $-$…
Luminous blue variable stars (LBVs) are of great interest in massive-star evolution as they experience very high mass-loss episodes within short periods of time. HR Car is a famous member of this class in the Galaxy. It has a large…
From recent reports on terrestrial heavy ion collision experiments it appears that one may not obtain information about the existence of asymptotic freedom (AF) and chiral symmetry restoration (CSR) for quarks of QCD at high density. This…
Applying the technique of dynamical maps we study the orbital stability of test particles in the Solar System in the space (a,e,i) defined by 0.1<a<38 au, 0<e<0.9 and 0<i<180 identifying the unstable and stable regions. We find stable…
The evolutionary state of blue supergiants is still unknown. Stellar wind mass loss is one of the dominant processes determining the evolution of massive stars, and it may provide clues on the evolutionary properties of blue supergiants. As…
We provide atmospheric parameters and rotational velocities of a large sample (~400) of O- and early B-type stars, analysed in a homogeneous and consistent manner, for use in constraining theoretical models. Comparison of the rotational…
We discuss moderate resolution spectra, multicolor photometry, and light curves of thirty-one of the most luminous stars and variables in the giant spiral M101. The majority are intermediate A to F-type supergiants. We present new…
Massive stars dominate the radiative and mechanical feedback of young stellar populations, yet their intense ultraviolet fields and strong winds are typically presumed to preclude Earth-like habitability. We quantify this expectation by…