G. A. H. Walker et al 2005 ApJ 635 L77 doi:10.1086/499362
G. A. H. Walker1, R. Kuschnig2, J. M. Matthews2, C. Cameron2, H. Saio3, U. Lee3, E. Kambe4, S. Masuda5, D. B. Guenther6, A. F. J. Moffat7, S. M. Rucinski8, D. Sasselov9 and W. W. Weiss10
Show affiliationsWe have extracted a 37 day light curve with a precision of 0.0012 mag per point for the Microvariability and Oscillations of Stars (MOST) guide star, HD 163868 (B5 Ve). Its rich frequency spectrum resembles that of a slowly pulsating B (SPB) star but, being a rapid rotator, we designate it SPBe. The 60 most significant periods lie in three distinct groups centered on 8 days and 14 and 7 hr. We demonstrate that the 14 and 7 hr periods can be modeled by two swarms of high-order, prograde sectorial g-modes (m = -1, -2), which are destabilized by the iron opacity bump. Our model also predicts a group of r-modes with periods near 2.3 days, which correspond to frequencies observed in the tail of the 8 day group. The remaining periodicities, between 7 and 11 days, cannot be explained by unstable modes in our model.
stars: early-type; stars: emission-line, Be; stars: individual (HD 163868); stars: oscillations; stars: rotation
Issue 1 (2005 December 10)
Received 2005 October 16, accepted for publication 2005 November 4
Published 2005 December 1
G. A. H. Walker et al 2005 ApJ 635 L77
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