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Absolute Wavelength Shifts — A New Diagnostic for Rapidly Rotating Stars

Published online by Cambridge University Press:  26 May 2016

Dainis Dravins*
Affiliation:
Lund Observatory, Box 43, SE-22100 Lund, Sweden

Abstract

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Accuracies reached in space astrometry now permit the accurate determination of astrometric radial velocities, without any use of spectroscopy. Knowing this true stellar motion, spectral shifts intrinsic to stellar atmospheres can be identified, for instance gravitational redshifts and those caused by velocity fields on stellar surfaces. The astrometric accuracy is independent of any spectral complexity, such as the smeared-out line profiles of rapidly rotating stars. Besides a better determination of stellar velocities, this permits more precise studies of atmospheric dynamics, such as possible modifications of stellar surface convection (granulation) by rotation-induced forces, as well as a potential for observing meridional flows across stellar surfaces.

Type
Session 1 Observations of Rotating Stars
Copyright
Copyright © Astronomical Society of the Pacific 2004 

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