GRO J0422+32 (= V518 Per) is a black-hole X-ray nova which went into outburst on August 5, 1992. Since then, we have been monitoring the decay light curve of...

According to its spectral type B2 Ib/I I (Klare & Neckel 1977; Schmidt & Carruthers 1996), HD163899 is a supergiant star. The star presents p and g-mode...

NLTE effects in iron lines are carefully investigated for the sunspot umbral model of Maltby et. al. (1986). Our model atom is realistic: it has hundreds of...

As part of a long term observational project, we are investigating the macroturbulent broadening in O and B supergiants (Sgs) and its possible connection with...

The spectrum of O and B Supergiants is known to be affected by an important extra line-broadening (usually called macroturbulence) that adds to stellar rotation...

The underlying ethos of Open Access is that the public should have the right to free access to the published results of all publicly funded academic and...

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The photospheric Mn I 539.4 nm line in the solar spectrum shows unusual variability with the solar cycle in that its depth decreases with increasing activity...