K. Tatebe and C. H. Townes 2006 ApJ 644 1145 doi:10.1086/503862
K. Tatebe1 and C. H. Townes1
Show affiliationsInterferometric measurements of stellar sizes in frequency bands ranging from the near-infrared to longer wavelengths give different results. Various explanations have been proposed to account for these variations in apparent size with wavelength, but none have been entirely consistent. We propose that thermal ionization in the stellar atmosphere and resulting opacity, primarily due to free-free electron-hydrogen collisions, play a significant role. Such an opacity has a quadratic dependence on photon wavelength and produces variations in the opacity of the atmosphere with wavelength, consistent with pertinent measurements. This may be particularly important for Mira-type stars, and two examples, o Ceti and W Hya, are analyzed as examples. For stars that are much smaller or with more concentrated mass, it is not likely to be significant.
stars: atmospheres; stars: fundamental parameters; stars: variables: other; techniques: interferometric
Issue 2 (2006 June 20)
Received 2006 January 10, accepted for publication 2006 March 3
K. Tatebe and C. H. Townes 2006 ApJ 644 1145
M Okabayashi et al 2002 Plasma Phys. Control. Fusion 44 B339
C. Zhu et al. 2009 ApJ 703 1176
V I Krauz 2006 Plasma Phys. Control. Fusion 48 B221
Daniel P. Marrone et al 2009 ApJ 701 L114
M. L. Lister et al. 2009 The Astronomical Journal 138 1874
E. Bittner et al 2007 EPL 78 58002
Felix Creutzig et al 2009 Environ. Res. Lett. 4 044011
Dominique M Durand 2009 J. Neural Eng. 6 050202
F. Bonnet et al 2008 EPL 82 56003