ar X iv : a st ro - p h / 98 05 20 4 v 1 1 5 M ay 1 99 8 A programme for electron - impact broadening parameter calculations of ionized rare - earth element lines

ar X iv : a st ro - p h / 98 05 21 3 v 1 1 5 M ay 1 99 8 Light element abundances in He - rich stars

We present an abundance analysis of light elements in He-rich stars. The analysis is based on both low and high resolution observations collected at ESO, La Silla, Chile in the optical region and includes 6 standards and 21 He-rich stars. Light-element abundances display a diverse pattern: they range from under-solar up to above-solar values.

ar X iv : a st ro - p h / 98 05 06 4 v 1 6 M ay 1 99 8 Mercury and platinum abundances in mercury - manganese stars

We report new results for the elemental and isotopic abundances of the normally rare elements mercury and platinum in HgMn stars. Typical overabundances can be 4 dex or more. The isotopic patterns do not follow the fractionation model of White et al (1976).

ar X iv : a st ro - p h / 98 05 20 5 v 1 1 5 M ay 1 99 8 The double - lined spectroscopic binary α Andromedae : orbital elements and elemental abundances

We performed a spectroscopic study of the SB2 Mercury-Manganese star α And. Our measurements of the secondary’s radial velocities result in improved orbital elements. The secondary shows abundances typical of the metallic-line stars: a Ca deficiency, small overabundances of the iron-peak elements, and 1.0 dex overabundances of Sr and Ba.

ar X iv : a st ro - p h / 98 05 24 3 v 1 1 9 M ay 1 99 8 ι Cas : Multi - element Doppler imaging and magnetic field geometry

In order to clarify the role of the magnetic field in generating abundance inhomogeneities in the atmospheres of Ap stars, we present new abundance Doppler images and an approximate magnetic field geometry for the Ap star ι Cas.

ar X iv : a st ro - p h / 95 05 14 5 v 1 3 1 M ay 1 99 5 Search for GRB counterparts