Bibcode
Kurtz, D. W.; Kawaler, S. D.; Riddle, R. L.; Reed, M. D.; Cunha, M. S.; Wood, M.; Silvestri, N.; Watson, T. K.; Dolez, N.; Moskalik, P.; Zola, S.; Pallier, E.; Guzik, J. A.; Metcalfe, T. S.; Mukadam, A. S.; Nather, R. E.; Winget, D. E.; Sullivan, D. J.; Sullivan, T.; Sekiguchi, K.; Jiang, X.; Shobbrook, R.; Ashoka, B. N.; Seetha, S.; Joshi, S.; O'Donoghue, D.; Handler, G.; Mueller, M.; Gonzalez Perez, J. M.; Solheim, J.-E.; Johannessen, F.; Ulla, A.; Kepler, S. O.; Kanaan, A.; da Costa, A.; Fraga, L.; Giovannini, O.; Matthews, J. M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 330, Issue 3, pp. L57-L61.
Advertised on:
3
2002
Citations
40
Refereed citations
27
Description
HR1217 is a prototypical rapidly oscillating Ap star that has presented
a test to the theory of non-radial stellar pulsation. Prior observations
showed a clear pattern of five modes with alternating frequency spacings
of 33.3 and 34.6μHz, with a sixth mode at a problematic spacing of
50.0μHz (which equals to the high-frequency side. Asymptotic
pulsation theory allowed for a frequency spacing of 34μHz, but
Hipparcos observations rule out such a spacing. Theoretical calculations
of magnetoacoustic modes in Ap stars by Cunha predicted that there
should be a previously undetected mode 34μHz higher than the main
group, with a smaller spacing between it and the highest one. In this
Letter, we present preliminary results from a multisite photometric
campaign on the rapidly oscillating Ap star HR1217 using the `Whole
Earth Telescope'. While a complete analysis of the data will appear in a
later paper, one outstanding result from this run is the discovery of a
newly detected frequency in the pulsation spectrum of this star, at the
frequency predicted by Cunha.