We build the tools that help make the search for life possible. UC Santa Cruz is home to the world-class instrumentation facilities of UCO/Lick Observatories and its Center for Adaptive Optics. UC Santa Cruz astronomers develop technology that helps observatories around the globe see farther and clearer.
In recent decades, astronomers have discovered thousands of planets outside our solar system, called exoplanets. The vast majority have been discovered indirectly by observing the host star and inferring the existence of a planet (e.g., the transit and doppler methods). Directly imaging an exoplanet is technically challenging because the faint light of the planet is lost in the glare of its host star. However, the rewards are great. The light emitted by or reflected from the surface of an exoplanet carries with it chemical fingerprints — clues about surface features, atmospheric conditions, and possibly even life.
Adaptive optics (AO) is a critical technology for direct imaging of exoplanets, and UC Santa Cruz has played a leading role in its development. AO systems sharpen the images obtained by ground-based telescopes by removing the blurring effects of turbulence in the Earth’s atmosphere. AO systems can also be used to control image distortions such as those introduced by the telescope itself (e.g. the slight misalignments in mirror segments in large telescopes like Keck).
Philip Hinz is working to develop new AO systems. In one such concept, the telescope’s secondary mirror is fabricated so that it can be deformed up to several thousand times a second. The development requires creating large and agile optical surfaces. Such advances will improve the efficiency of the systems and support future instrument concepts, such as SCALES, that aim to directly image exoplanets in the infrared where background light from the optics themselves add extra noise. This technology is being explored for the Keck Telescopes with the goal of enabling new technologies for the Thirty Meter Telescope, where lower background light can aid in imaging and characterizing rocky, potentially Earth-like planets orbiting our stellar neighbors.
Rebecca Jensen-Clem is working to develop new technologies for exoplanet imaging and extreme adaptive optics systems. She is currently leading a demonstration of a technique called predictive wavefront control at W. M. Keck Observatory. This technique is key to directly imaging planets orbiting other stars in our galaxy because the turbulence in our own atmosphere blurs star and planet light faster than our adaptive optics systems — designed to compensate for such turbulence — can correct it. Predicting the future state of the turbulence will allow observers at W. M. Keck Observatory to directly image fainter exoplanets than ever before, as well as search for planets around very faint stars. Predictive control is a crucial technology for habitable-zone exoplanet imaging with the next generation of giant segmented mirror telescopes.
Andrew Skemer, associate professor of astronomy and astrophysics, is developing a new instrument for the Keck Telescopes that will be dedicated to exoplanet spectroscopy. Skemer’s team received funding to complete the design stage and purchase or fabricate several critical components for an instrument, called the Santa Cruz Array of Lenslets for Exoplanet Spectroscopy (SCALES). SCALES is designed to maximize the ability of astronomers to detect and characterize directly-imaged exoplanets in the thermal infrared wavelengths where they peak in brightness. Directly imaged planets are generally far enough away from their host stars that they emit the majority of their light in the thermal infrared. By operating at longer wavelengths, SCALES will extend the wavelength range we use to characterize exoplanets, and will also discover new exoplanets that are not detectable with near-infrared instruments.
Emily Martin, a postdoctoral fellow working with Skemer, is developing a new tool to reside at Lick Observatory, called the Planet as Exoplanet Analog Spectrograph (PEAS). The instrument will enable spectroscopic observations of solar system planets as if they were distant exoplanets. It employs an integrating sphere to reduce the complex surface features seen on nearby solar system planets into an unresolved, uniform light source akin to what we will see from a distant exoplanet. Light is then is fiber-fed to an infrared & optical spectrograph. The goal is to produce an atlas of spectra to help astronomers interpret exoplanet observations and design future exoplanet instruments.
Although these projects are very different from one another, they will all provide critical new knowledge and capabilities needed to discover and understand the full diversity of planets to be found beyond our solar system.
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