Issue 15 - May 2015
By Rafael Millan-Gabet
The Large Binocular Telescope Interferometer (LBTI), P.I. Phil Hinz, University of Arizona, has made tremendous progress in instrument performance over the last year. We have demonstrated null calibration at the 500 ppm level for a bright (7 Jy) star. For the spectral type of that particular star (A3V), this translates to 8 “zodi" sensitivity, or 15 zodi if it had been a star like the Sun located at 10 pc.
Pending the recommendations of an Operational Readiness Review being held this spring, the project expects to begin the NASA exozodi survey (HOSTS, or Hunt for Observable Signatures of Terrestrial Systems) in Fall 2015 (as soon as the Summer Monsoon season ends) and to continue for a minimum of two years. At the same time, further instrument improvements will be implemented during the first year of operations, with a goal of achieving a typical sensitivity of 6 zodi for the HOSTS target list.
Meanwhile, three papers have been published by the HOSTS Science Team: on the exozodi survey target list (Weinberger et al., ApJ, 2015), on the modeling and interpretation of LBTI nulling observables (Kennedy et al., ApJ, 2015), and on the first exozodi detection by LBTI, for the well-studied object eta Corvi (Defrere et al, ApJ, 2015).