We have been monitoring the position of the very faint X-ray transient XTE J1728-295 (= IGR J17285-2922, ATel #2823, #2824, #2825) with the Faulkes Telescopes North and South throughout its outburst. Data were acquired on thirteen dates from 1st September until 28th October, mostly in I- band and R-band. Of the original seven stars detected with

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear

Aims: We study how IMF sampling affects the ionizing flux and emission line spectra of low mass stellar clusters. Methods: We performed 2 × 106 Monte Carlo simulations of zero-age solar-metallicity stellar clusters covering the 20-106 M&sun; mass range. We study the distribution of cluster stellar masses, Mclus, ionizing fluxes, Q(H0), and

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We present synthetic spectral energy distributions (SEDs) for single-age, single-metallicity stellar populations (SSPs) covering the full optical spectral range at moderately high resolution [full width at half-maximum (FWHM)=2.3Å]. These SEDs constitute our base models, as they combine scaled-solar isochrones with an empirical stellar spectral