Title:
Interferometric observations of R Leonis in the K band. First direct detection of the photospheric pulsation and study of the atmospheric intensity distribution
Authors:
Perrin, G.; Coudé du Foresto, V.; Ridgway, S. T.; Mennesson, B.; Ruilier, C.; Mariotti, J.-M.; Traub, W. A.; Lacasse, M. G.
Affiliation:
AA( Observatoire de Paris, DESPA, F-92195 Meudon, France), AB( Observatoire de Paris, DESPA, F-92195 Meudon, France), AC(National Optical Astronomy Observatories, Tucson, AZ 85726-6732, USA), AD( Observatoire de Paris, DESPA, F-92195 Meudon, France), AE( Observatoire de Paris, DESPA, F-92195 Meudon, France), AF( Observatoire de Paris, DESPA, F-92195 Meudon, France), AG(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA), AH(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA)
Journal:
Astronomy and Astrophysics, v.345, p.221-232 (1999) (A&A Homepage)
Publication Date:
05/1999
Origin:
A&A
A&A Keywords:
TECHNIQUES: INTERFEROMETRIC, STARS: FUNDAMENTAL PARAMETERS, STARS: INDIVIDUAL: R LEO, STARS: AGB AND POST-AGB, INFRARED: STARS
Abstract Copyright:
(c) 1999: Astronomy & Astrophysics
Bibliographic Code:
1999A&A...345..221P

Abstract

The Mira-type star R Leonis was observed at two different epochs in the K band with the FLUOR beam combiner on the IOTA interferometer. A variation of diameter is clearly detected for the very first time at this wavelength revealing an apparent pulsation of atmospheric layers very close to the stellar photosphere. We discuss the excess of visibility measured at high spatial frequencies and show that they very likely reveal smaller diameters of the photosphere (22-24 mas) than those deduced on the basis of shorter frequency components. This smaller diameter makes R Leonis a fundamental pulsator. Mira models are compared to our data and a disagreement with spatial intensity distribution and dynamical behaviour is found. based on observations collected at the IOTA interferometer, Whipple Observatory, Mount Hopkins, Arizona.