Precision interferometry: Towards exo-Earth imaging and 30m-class telescopes
Steve Ertel (Steward Observatory and the Large Binocular Telescope Observatory)
Compared to filled-aperture telescopes, astronomical optical long-baseline interferometry typically provides higher angular resolution and higher-precision spatial measurements at the cost of fidelity, dynamic range, and consequently contrast of reconstructed images. I use the term precision interferometry to refer to efforts of overcoming this limitation through more precise measurements of the classical interferometric observables (visibilities and closure phases) or though circumventing them altogether using nulling or Fizeau (imaging) interferometry. Over the past almost two decades, these efforts have enabled the spatially resolved observations of the habitable zones and closer in of planetary systems with a sensitivity to detect circumstellar, exozodiacal dust. This dust poses both an opportunity to study the architectures and dynamics of planetary systems near their habitable zones and a potential obstacle to directly imaging rocky, habitable-zone planets. Its study is thus crucial for enabling and preparing for a future exo-Earth imaging mission such as the Habitable Worlds Observatory. I will review our work on exozodiacal dust with the Large Binocular Telescope Interferometer (LBTI) and the Very Large Telescope Interferometer (VLTI). I will further present our efforts to enable high-fidelity imaging at the angular resolution of a 23m telescope with the LBTI for general astronomical observations. This work makes the LBTI a critical pathfinder for future 30m-class telescopes. Both exo-Earth imaging and the completion and exploitation of 30m-class telescopes are major priorities of the US community as outlined in the National Academy’s Astro2020 Decadal Survey. I will then close the loop and conclude my talk by outlining our efforts to obtain the first direct-imaging detection of a rocky, habitable-zone planet around a nearby, Sun-like star with the LBTI.
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