The Large Fiber Array Spectroscopic Telescope: trade-off study of high-resolution spectrometer architectures

Abstract

A combination of large collecting aperture telescopes and highly efficient high-resolution spectrometers is crucial for key cases in exoplanet science in particular the search for biomarkers. Here, we present a design study exploring high-resolution spectrometer concepts for the Large Fiber Array Spectroscopic Telescope (LFAST), an array overcoming the limitations of single-aperture telescopes by combining a large number of 0.76 m telescopes into one facility with a collecting area comparable to an ELT. Every individual telescope couples light to a separate optical fiber, which is fed to the proposed spectrometers. The paper investigates design trade-offs between single, very large spectrometers in the visible and the near-IR capable of spectrally analyzing the combined fiber output of a large number of telescopes, and multiple smaller spectrometers coupled to sub-arrays of equivalent 10-m, 3-m and individual 0.76-m telescopes.