PIONIERing Diameter Measurements of Globular Cluster Giants

Autor(en)

J. Hron, J. L. Bouquin, T. Lebzelter, C. Paladini, I. Soszynski, J.-P. Berger, H. M. J. Boffin, M. Wittkowski

Abstrakt

We present an attempt to resolve for the first time one of the brightest long period variables in the globular cluster 47 Tuc with PIONIER in the H band. Based on model atmospheres and observations of local LPVs, the predicted visibilities were about 0.9, i.e. they are at the limit of feasibility with PIONIER. The observations show that the star is unresolved with an upper limit of 0.44 mas for the uniform disk (UD) diameter in the H band. This is in agreement with the predictions from stellar evolution models and from a dynamic model with similar stellar parameters. Spatial frequencies of B[m] / λ[μm]> 150 are necessary to resolve this star and to distinguish between different models, but these are beyond those currently accessible with VLTI.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

European Southern Observatory (Germany)

Seiten

485 - 486

Publikationsdatum

08-2015

ÖFOS 2012

103004 Astrophysik, 103003 Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/pioniering-diameter-measurements-of-globular-cluster-giants(89790f37-0671-49c3-8ff5-9e18952ed4f5).html