Collaborative Research: A New Instrument for the Large Binocular Telescope to Expand Study of the Composition of Exoplanetary Atmospheres

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

During the past 20 years, astronomers have discovered thousands of planets around other stars. It is extremely hard to study these so-called "exoplanets," because the glare of light from their parent stars hides them. Turbulence in Earth's atmosphere greatly complicates studies using large ground-based telescopes. To counteract this effect, most large telescopes now employ a technique called "adaptive optics," or AO, to stabilize the image of a star. With the image stabilized, astronomers can use other devices to suppress most of the starlight, enabling them to study the much fainter exoplanets around them. Many of the giant exoplanets radiate at thermal infrared wavelengths. Capitalizing on this fact, the Investigators will develop a spectrograph to operate at these wavelengths for installation on the Large Binocular Telescope, or LBT. The LBT, located on a mountaintop in Arizona, consists of twin 8.4-meter-diameter telescopes that already use AO. A prototype of the new spectrograph is already in operation on the LBT. This project serves the national interest by developing a state-of-the-art instrument that will be used to promote our knowledge of the composition of exoplanets. The Intellectual Merit of the project comes from the ability of the new spectrograph to carry out studies of exoplanets, disks around young stars, and bodies in our Solar System. The Broader Impacts involve the training of graduate students who will become the next generation of instrument developers. The Investigators will develop the world's first adaptive-optics-fed, integral-field spectrograph for the thermal infrared and integrate it into the twin 8.4-meter Large Binocular Telescope. A prototype of the instrument, dubbed "ALES," developed by the same team, is already in operation and producing high-contrast imaging and spectroscopy. The modular aspect of the instrument, which is afforded by filter wheels that contain a variety of optical components, is a novel and flexible feature. The Intellectual Merit of the project derives from its potential to obtain spectra of gas-giant exoplanets and other astronomical objects that radiate in the thermal infrared, pointing the way to interesting science observations in the future. The Broader Impacts are focused on developing graduate students with the skills necessary to design the next generation of astronomical instrumentation.