Showing papers by "Charles H. Townes published in 2009"
TL;DR: In this paper, the authors presented results from a spectro-interferometric study of the Miras o Cet, R Leo, and W Hya obtained with the Keck Aperture Masking Experiment from 1998 September to 2002 July.
Abstract: We present results from a spectro-interferometric study of the Miras o Cet, R Leo, and W Hya obtained with the Keck Aperture Masking Experiment from 1998 September to 2002 July. The spectrally dispersed visibility data permit fitting with circularly symmetric brightness profiles such as a simple uniform disk (UD). The stellar angular diameter obtained over up to ~ 450 spectral channels spanning the region 1.1-3.8 μm is presented. Use of a simple UD brightness model facilitates comparison between epochs and with existing data and theoretical models. Strong size variations with wavelength were recorded for all stars, probing zones of H2O, CO, OH, and dust formation. Comparison with contemporaneous spectra extracted from our data shows a strong anticorrelation between the observed angular diameter and flux. These variations consolidate the notion of a complex stellar atmosphere consisting of molecular shells with time-dependent densities and temperatures. Our findings are compared with existing data and pulsation models. The models were found to reproduce the functional form of the wavelength versus angular diameter curve well, although some departures are noted in the 2.8-3.5 μm range.
59 citations
TL;DR: The diameter of Betelgeuse (α Orionis) has been measured at a wavelength of 11.15 μm using the Infrared Spatial Interferometer over the past 15 years as discussed by the authors.
Abstract: The diameter of Betelgeuse (α Orionis) has been measured at a wavelength of 11.15 μm using the Infrared Spatial Interferometer over the past 15 years. During this 1993-2009 time period the star's size has decreased systematically by 15%.
23 citations