Washington, DC—Carnegie’s Anat Shahar is the lead investigator on an interdisciplinary, multi-institution research team that this spring was awarded nearly $1.5 million from the Alfred P. Sloan Foundation to understand the chemical makeup of our galaxy’s most common planets with a goal of developing a framework for detecting chemical signatures of life on distant worlds.  

Since the first planet orbiting a Sun-like star beyond our Solar System was discovered in the mid-1990s, astronomers have revealed that the Milky Way is teeming with planets. To search for evidence of life on these thousands of other worlds, researchers are on the hunt for chemical markers that could only be produced by biological processes. This means they must be able to rule out every possible non-biological origin for these chemical signatures.

The AEThER or Atmospheric, Empirical, Theoretical, and Experimental Research project aims to determine the abiotic atmospheric composition of gas dwarfs, or sub-Neptunes, as well as other, smaller rocky bodies.  Although our own Solar System doesn’t have any sub-Nepture or super-Earth sized planets, they are the most common type of exoplanet discovered so far.

“To understand the non-biological processes that determined a planet’s atmosphere, you have to understand its formation and evolution,” Shahar explained. “A planet’s atmosphere is influenced by its accretion from the dust and gas surrounding a young star and the differentiation of this material into distinct layers, and is later modified by what’s happening on its surface, including volcanism and tectonic activity.”

Shahar and her team—including colleagues and collaborators from Carnegie, Howard University, University of Washington, the Observatoire de Paris, the Harvard & Smithsonian Center for Astrophysics, University of Maryland, University of Rochester, Oxford University, and UCLA—aim to reveal the intricate connections between a planet’s interior, surface, and atmosphere in order to eliminate every possible “false positive” biosignature. They believe this will open the door to a reliable method of life detection.

The next generation of ground- and space-based telescopes will enable astronomers to determine the compositions of gas giant exoplanet atmospheres with never-before-seen detail. But to truly develop a foolproof method for detecting biosignatures, more than one area of expertise is needed, which is why AEThER will deploy a multi-disciplinary approach, including observations, experiments, and modeling.

“Carnegie’s longstanding leadership in laboratory experiments and model development revealing the conditions found in the interiors of our own and other planets, as well as the world-class telescopes at our Las Campanas Observatory, make this the logical home for such an ambitious project,” said Richard Carlson, Director of the institution’s Earth and Planets Laboratory.

Another component of the Sloan grant will fund training and mentoring undergraduate and graduate students with the hope of increasing the diversity amongst the next generation of Earth and planetary scientists.

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The ALFRED P. SLOAN FOUNDATION is a not-for-profit, mission-driven grantmaking institution dedicated to improving the welfare of all through the advancement of scientific knowledge. Established in 1934 by Alfred Pritchard Sloan Jr., then-President and Chief Executive Officer of the General Motors Corporation, the Foundation makes grants in four broad areas: direct support of research in science, technology, engineering, mathematics, and economics; initiatives to increase the quality, equity, diversity, and inclusiveness of scientific institutions and the science workforce; projects to develop or leverage technology to empower research; and efforts to enhance and deepen public engagement with science and scientists.

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Earth/Planetary Science