A Southwest Research Institute scientist is using big data to help the scientific community characterize exoplanets, particularly alien worlds orbiting nearby stars. Of particular interest are exoplanets that could harbor life.
“At first scientists focused on temperatures, looking for exoplanets in the ‘Goldilocks zone’ — neither too close, nor too far from the star, where liquid water could exist,” said Dr. Natalie Hinkel, a planetary astrophysicist at SwRI. “But the definition of habitability is evolving beyond liquid water and a cozy temperature.”
The planets also need the building blocks for life (such as hydrogen, carbon, nitrogen, oxygen and phosphorus) as well as a rocky composition (including elements such as iron, silicon and magnesium) for a planet to be habitable. Plus, active geochemical cycles are necessary to distribute these elements around the world. As seen on Earth, a protective atmosphere is also a necessity for life.
“With current technology, we can’t measure the composition of an exoplanet’s surface, much less its interior,” Hinkel said. “But we can measure the abundance of elements in a star spectroscopically, studying how light interacts with the elements in a star’s upper layers. Using these data, scientists can infer what a star’s orbiting planets are made of, using stellar composition as a proxy for its planets.”
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