Anthony F J Moffat

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Context. Asteroseismology has great potential for the study of metal-poor stars due to its sensitivity to determine stellar ages. Solid detections of oscillation frequencies in stars with well constrained fundamental parameters, combined with a known rotation period, should significantly advance our understanding of stellar structure and evolution in(More)
BAT99-129 in the LMC is one among a handful of extra-galactic eclipsing Wolf-Rayet binaries known. We present blue, medium-resolution, phase-dependent NTT-EMMI spectra of this system that allow us to separate the spectra of the two components of the binary and to obtain a reliable orbital solution for both stars. We assign an O5V spectral type to the(More)
Using MOST (Microvariability and Oscillations of STars) satellite guide star photometry, we have discovered a metallic A star showing hybrid pand gmode pulsations. HD 114839 was observed nearly continuously for 10 days in March, 2005. We identify frequencies in three groups: the first centered near 2 cycles/day, in the γ Dor pulsation range, and two others(More)
The β Cephei star δ Ceti was considered one of the few monoperiodic variables in the class. Despite (or perhaps because of) its apparently simple oscillation spectrum, it has been challenging and controversial to identify this star’s pulsation mode and constrain its physical parameters seismically. Broadband timeresolved photometry of δCeti spanning 18.7(More)
We demonstrate that a seismic analysis of stars in their earliest evolutionary phases is a powerful method with which to identify young stars and distinguish their evolutionary states. The early star that is born from the gravitational collapse of a molecular cloud reaches at some point sufficient temperature, mass, and luminosity to be detected. Accretion(More)
Progress in understanding the formation and evolution of planetary nebulae (PN) has been restricted by a paucity of well-determined central star masses. To address this deficiency we aim to (i) significantly increase the number of known eclipsing binary central stars of PN (CSPN), and subsequently (ii) directly obtain their masses and absolute dimensions by(More)
We present 10.27 hrs of photometry of the roAp star HD 134214 obtained by the MOST 1 satellite. The star is shown to be monoperiodic and oscillating at a frequency of 2948.97 ± 0.55 μHz. This is consistent with earlier ground based photometric campaigns (e.g. Kreidl et al. 1994). We do not detect any of the additional frequencies identified in the recent(More)
  • Y Nazé, J M Hartwell, +5 authors V S Niemela
  • 2002
We present results from a Chandra observation of the NGC346 cluster. This cluster contains numerous massive stars and is responsible for the ionization of N66, the most luminous H ii region and the largest star formation region in the SMC. In this first paper, we will focus on the characteristics of the main objects of the field. The NGC346 cluster itself(More)
Aims. To assess the nature of three WNh stars in the SMC, to constrain stellar evolution beyond the main sequence at low metallicity, and to investigate the metallicity dependence of the clumping properties of massive stars. Methods. We compute atmosphere models to derive the stellar and wind properties of the three WNh targets. A(More)
The mass-loss rates of hot, massive, luminous stars are considered a decisive parameter in shaping the evolutionary tracks of such stars and influencing the interstellar medium on galactic scales. The small-scale structures (clumps) omnipresent in such winds may reduce empirical estimates of mass-loss rates by an evolutionarily significant factor of ≥ 3. So(More)