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Radial velocity study of the roAp star HR 1217
L.A. Balona1 and W. Zima2
1 South African Astronomical Observatory, P.O. Box 9, Observatory 7935
Cape Town, South Africa
2Astronomisches Instituut der Universitaat Wien, Turkenschanzstr. 17, A-1180, Wien, Austria
We analyze 1160 high-dispersion echelle spectra of the roAp star HR 1217
obtained over two two-week runs. Radial velocities were obtained by
cross-correlating with three different templates: a spectrum of a normal
star, a spectrum of HR 1217 itself and a spectrum containing only lines of
rare-earth elements. We show that rotational modulation is present in the
radial velocities calculated using the normal star template and the
rare-earth template, but with opposite phases. The roAp pulsations are not
detected in the radial velocities from the normal star template, are weekly
present in the radial velocities using a template of the star itself, but are
of large amplitude in the radial velocities obtained using a template
containing only rare-earth lines. The pulsation frequencies are, as far as
we can tell, identical to those obtained photometrically, although only the
mode of largest amplitude is independently detected. These observations
confirm that the pulsations in roAp stars are strongly concentrated at the
magnetic poles which is also the location where the rare-earth elements are
overabundant. A strong core-wing anomaly is present in the H
Last changed: 2002/Jun/26
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