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Seminars at FGG

Optical Interferometry with the VLTI and Arcetri's Program on Young Stars

Speaker: Fabrizio Massi (INAF - Oss. di Arcetri)

Date and time: 2013-07-25 12:30

Although the first successful experiments of optical interferometry date back to 1920, with the first measurements of stellar diameters by Michelson and Pease, only since the early 1990s have large arrays of telescopes become operational for carrying out optical interferometry on a routine basis. The Very Large Telescope Interferometer (VLTI), situated in Cerro Paranal (Chile) and operated by ESO, is now the largest facility its kind, comprising four 8.2-m telescopes (UTs) and another four 1.8-m movable auxiliary telescopes (ATs). In 1997, Arcetri Observatory became involved in the development of AMBER, a beam-combiner spectrograph now fully operational at the VLTI, along with other French and German partner institutes. AMBER saw first light in 2002, and Arcetri obtained 1200 hours of guaranteed time with the ATs as a reward for its participation in the project. This time has been mostly spent in a program of near-infrared interferometric observations of circumstellar disks around Herbig Ae/Be stars, i.e. pre-main sequence stars of intermediate mass (2-10 Msun). In this talk, I will briefly review the development of optical interferometry from Michelson's experiments to the VLTI. Then, after an introduction to the basic concepts of optical interferometry, I will show a few results of Arcetri's observational program, including the first clear image at milli-arcsec resolution of the innermost part of a circumstellar disk around a nearby HAeBe star (HR5999), published on AA in 2011.