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Séminaire du Jeudi 8 Décembre 2011

A deep insight into the structure and environment of stars with phase closure nulling

Alain Chelli (IPAG)
Jeudi 8 Décembre - 11 h 00
Salle Manuel Forestini - IPAG

Phase closure nulling (PCN) is an interferometric mode consisting in observing around the visibility zero of a star. Doing so, the centro-symmetric stellar light is cancelled, revealing asymmetries like spots or companions. We present the very first results of a PCN observational campain in the K band, on Sirius A and a sample of late-type giants fully resolved by the AMBER instrument on the VLTI. At a spectral resolution of 1500, we measure the variations of the visibility zero location as a fonction of the wavelength, with a precison of a few micro-arcsecond. Along with extremely precise diameter estimates, PCN allows us to identify signatures of : molecular lines (CO), rotation, and possibly companions.


Sous la tutelle de:

tutelles

Sous la tutelle de:

CNRS Université Grenoble Alpes