HD 9289: a new rapidly oscillating Ap star similar to the well-studied, multiperiodic roAp star HR 1217

The sixth frequen y of roAp star HR 1217 Margarida

Time - series spectroscopy of the rapidly oscillating Ap star HR 3831

We present time-series spectroscopy of the rapidly oscillating Ap star HR 3831. This star has a dominant pulsation period of 11.7 minutes and a rotation period of 2.85d. We have analysed 1400 intermediate-resolution spectra of the wavelength region 6100– 7100Å obtained over one week, using techniques similar to those we applied to another roAp star, α Cir. We confirm that the Hα velocity amplit...

HD 12098 - A new northern hemisphere roAp star

We present the analysis of 65 hours of high speed photometric observations of HD 12098 taken from State Observatory, Naini Tal and Gurushikhar Observatory, Mt. Abu on sixteen nights spanning from November 1999 to November 2000. HD 12098 is the first rapidly oscillating Ap star discovered from the ‘Naini Tal-Cape survey for northern hemisphere roAp stars’. It is the 32nd in the complete list. HD...

Seismic tests of the structure of rapidly oscillating Ap stars : HR 1217

HR 1217 is probably the best studied multiperiodic rapidly oscillating Ap star, which makes this star a test case for the seismic analysis of these complex stars. In this paper, we combine the observational data available for HR 1217 and use these data to constrain theoretical models appropriate for this star. In particular, we try to establish which unknown model parameters are the most releva...

Variations of the Ap star HD 208217 ?

We present a new determination of the rotation period of the Ap star HD 208217 based on photometric and magnetic measurements. The variations of this star are remarkable by the strong anharmonicity of its lightcurves in all colours as well as by the double wave of its mean magnetic field modulus variations.