We present a comprehensive study of the massive binary system HM1~8, based on multi-epoch high resolution spectroscopy, $V$-band photometry and archival X-ray data. Spectra from OWN Survey, optical monitoring Southern O WN stars, are used to analyse spectral morphology perform quantitative spectroscopic analysis both stellar components. The primary secondary components classified as O4.5~IV(f) ...

We have used the Sydney University Stellar Interferometer to measure the angular diameter of α Cir. This is the first detailed interferometric study of a rapidly oscillating A (roAp) star, α Cir being the brightest member of its class. We used the new and more accurate Hipparcos parallax to determine the radius to be 1.967 ± 0.066 R . We have constrained the bolometric flux from calibrated spec...

The observed constraints on the variability of the proton to electron mass ratio μ and the fine structure constant α are used to establish constraints on the variability of the Quantum Chromodynamic Scale and a combination of the Higgs Vacuum Expectation Value and the Yukawa couplings. Further model dependent assumptions provide constraints on the Higgs VEV and the Yukawa couplings separately. ...

We present an analysis of high resolution optical spectra for a sample of very young, midto late M, low-mass stellar and substellar objects: 11 in the Upper Scorpius association, and 2 (GG Tau Ba and Bb) in the Taurus star-forming region. Effective temperatures and surface gravities are derived from a multifeature spectral analysis using TiO, Na I and K I , through comparison with the latest sy...

In support for the ISO Mission it has been necessary to establish a set of asteroids as photometric standards for the photometric calibration of the instruments (M uller & Lagerros 1998). The new standards are described as rotating ellipsoids. Illumination geometry, heat transfer due to non-zero thermal inertia and surface structure/porosity are taken into account. The characteristic properties...

The fundamental parameters approach to line profile fitting uses physically based models to generate the line profile shapes. Fundamental parameters profile fitting (FPPF) has been used to synthesize and fit data from both parallel beam and divergent beam diffractometers. The refined parameters are determined by the diffractometer configuration. In a divergent beam diffractometer these include ...

The natural choice for the fundamental parameters of QCD are the renormalization group invariant (RGI) quark masses, Mi, i = u, d, ..., and the Λ-parameter. The RGI masses do not depend on a renormalization scheme and the scheme dependence of the Λ-parameter is exactly given by a one-loop coefficient. These quantities are in principle free of perturbative uncertainties. Their determination from...

We analyze the effect of variation of fundamental couplings and mass scales on primordial nucleosynthesis in a systematic way. The first step establishes the response of primordial element abundances to the variation of a large number of nuclear physics parameters, including nuclear binding energies. We find a strong influence of the n−p mass difference (for the He abundance), of the nucleon ma...

A temperature scale for Cepheids is presented, based on Geneva photometry. It uses new atmosphere models computed at various values of microturbulent velocity. The scale so-obtained is compared to other ones and the importance of microturbulence effects is shown. This calibration is applied to 20 Cepheids for which the variation of microturbulence is known. The detailed variations of temperatur...

We determine the basic physical characteristics of eight Gamma-Ray Bursts (GRB) – 980519, 990123, 990510, 991028, 991216, 000301c, 000926 and 010222 – by modelling the broadband emission of their afterglows. We find that the burst kinetic energies after the GRB phase are well clustered around a mean value of 3 × 10 ergs. In contrast, the energy release in γ-rays, after correcting for collimated...