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

Pulsational amplitude growth of the star KIC3429637 (HD178875) in the context of Am and ρ Pup stars

S. J. Murphy, A. Grigahcène, E. Niemczura, D. W. Kurtz, K. Uytterhoeven

Abstract
KIC3429637 (HD178875) is a δ Sct star whose light-curve shows continuous pulsational amplitude growth in Kepler Mission photometry. Analysis of the three largest amplitude peaks in the Fourier transform indicates different growth rates for all three. We have ruled out instrumental causes, and determine the amplitude growth to be intrinsic to the star. We calculate time-dependent convection models and compare them with the observations. We confirm earlier characterisations that KIC3429637 is a marginal Am star through the analysis of new spectroscopic data. With the data presently available, a plausible cause of the amplitude growth is increasing pulsational driving as evolutionary changes shift the He II driving zone deeper in this ρ Puppis star. If this model is correct, then we are watching real-time stellar evolutionary changes.

Keywords
stars: chemically peculiar – stars: individual: HD178875 – stars: oscillations – stars: variables: δ Scuti.

Monthly Notices of the Royal Astronomical Society
Volume 427, Page 1418
December 2012

>> 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