We present a detailed comparison of the ionizing spectral energy distributions (SEDs) predicted by four modern stellar atmosphere codes, TLUSTY, CMFGEN, WM-basic and FASTWIND. We consider three sets of stellar parameters representing a late O-type dwarf (O9.5V), a mid-O-type (O7V) dwarf and an early O-type dwarf (O5.5V). We explore two different

Analyses of the abundances of neutron-capture elements have led to the belief that these elements in metal-poor stars are r-process products with relative abundances closely resembling those found in the Solar system. This picture was challenged by Magain, who found that a pure r-process mix of the barium isotopes was inconsistent with the mix of

With a 6.5-meter diameter primary mirror in space and a wavelength coverage from the visible to the mid-infrared, the James Webb Space Telescope (JWST) will soon open new windows to scrutinize transiting exoplanets' atmospheres. It will provide missing clues to understand hot Jupiter's atmospheres such as the relative abundances of molecular

Context. The link between how bipolar planetary nebulae are shaped and their central stars is still poorly understood. Aims: This paper investigates the kinematics and shaping of the multipolar nebula M 1-75, and briefly discusses the location and nature of its central star. Methods: Fabry-Perot data from GHαFAS on the WHT that samples the Doppler

The molecular phase of the interstellar medium (ISM) in galaxies offers fundamental insight for understanding star-formation processes and how stellar feedback affects the nuclear activity of certain galaxies. We present here Large Millimeter Telescope spectra obtained with the Redshift Search Receiver, a spectrograph that covers simultaneously the

We present an optical spectroscopic study of the black hole X-ray transient V4641 Sgr (=SAX J1819.3-2525) covering the 1999, 2002, and 2004 outbursts. The spectra were taken over 22 different epochs during the low-luminosity phases that follow the sharp and bright outburst peaks displayed by the system. The data reveal the frequent presence of wind