SIMBAD references

1999MNRAS.302..381B - Mon. Not. R. Astron. Soc., 302, 381-390 (1999/January-2)

Spectroscopy of the roAp star alpha Cir - II. The bisector and equivalent width of the H-alpha line.

BALDRY I.K., VISKUM M., BEDDING T.R., KJELDSEN H. and FRANDSEN S.

Abstract (from CDS):

We present bisector measurements of the H α line of the rapidly oscillating Ap (roAp) star α Cir, obtained from dual-site observations with medium-dispersion spectrographs. The velocity amplitude and phase of the principal pulsation mode vary significantly, depending on the height in the H α line, including a phase reversal between the core and the wings of the line. This supports the theory, suggested in Paper I, of a radial pulsational node in the atmosphere of the star. Blending with metal lines partially affects the H α bisector results, but probably not enough to explain the phase reversal.

We have also detected changes in the equivalent width of the line during the pulsation, and measured the oscillatory signal as a function of wavelength across the Hα region.


Abstract Copyright: 1998, Royal Astronomical Society

Journal keyword(s): techniques: spectroscopic - stars: chemically peculiar - stars: individual: α Cir - stars: oscillations

Simbad objects: 1

goto Full paper

goto View the references in ADS

To bookmark this query, right click on this link: simbad:1999MNRAS.302..381B and select 'bookmark this link' or equivalent in the popup menu