A new concept for the combination of optical interferometers and high-resolution spectrographs

Abstract

The combination of high spatial and spectral resolution in optical astronomy enables new observational approaches to many open problems in stellar and circumstellar astrophysics. However, constructing a high-resolution spectrograph for an interferometer is a costly and time-intensive undertaking. Our aim is to show that, by coupling existing high-resolution spectrographs to existing interferometers, one could observe in the domain of high spectral and spatial resolution, and avoid the construction of a new complex and expensive instrument. We investigate in this article the different challenges which arise from combining an interferometer with a high-resolution spectrograph. The requirements for the different sub-systems are determined, with special attention given to the problems of fringe tracking and dispersion.Exp Astron (2010) 27:157-186 combination of the VLTI (Very Large Telescope Interferometer) with UVES (UV-Visual Echelle Spectrograph) is carried out, and several other specific instrument pairings are discussed. We show that the proposed combination of an interferometer with a high-resolution spectrograph is indeed feasible with current technology, for a fraction of the cost of building a whole new spectrograph. The impact on the existing instruments and their ongoing programs would be minimal.

Stellar Obliquities in Exoplanetary Systems

“…Optical and near-infrared interferometers can resolve the disks of main-sequence stars in the solar neighborhood. If equipped with a spectrograph capable of resolving stellar absorption lines, an interferometer can measure the orientation of the stellar rotation axis as projected on the sky plane (Albrecht et al 2010). The approaching and receding halves of the stellar disk have slightly different locations on the sky.…”