Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

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

M. S. Cunha, J. M. Fernandes, M. J. P. F. G. Monteiro

Abstract
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 relevant to reproduce the seismic data. We find that the interior chemical composition has more impact in the theoretical oscillation spectrum of HR 1217 than parameters related to the modelling of convection. Models with lower abundances of heavy elements and larger abundances of helium produce oscillation spectra that are closer to that observed. However, like Matthews et al., we show that it is difficult to find a plausible model that can reproduce the seismic observations of HR 1217, when the uncertainties in the observables are not taken into account, unless a complementary effect is added in order to account for a decrease in the expected large frequency separations.

Keywords
chemically peculiar - star individual: HR 1217 - star: magnetic fields - stars: oscillations - stars variables: other

Monthly Notices of the Royal Astronomical Society
Volume 343, Page 831
August 2003

>> ADS>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website