Detection Of Water Vapor In The Atmosphere Of A Hot Jupiter
Although liquid water covers a majority of Earth’s surface, scientists are still searching for planets outside of our solar system that contain water. Researchers at Caltech and several other institutions have used a new technique to analyze the gaseous atmospheres of such extrasolar planets and have made the first detection of water in the atmosphere of the Jupiter-mass planet orbiting the nearby star tau Boötis. With further development and more sensitive instruments, this technique could help researchers learn about how many planets with water—like Earth—exist within our galaxy.
Scientists have previously detected water vapor on a handful of other planets, but these detections could only take place under very specific circumstances, says graduate student Alexandra Lockwood, the first author of the study. “When a planet transits—or passes in orbit in front of—its host star, we can use information from this event to detect water vapor and other atmospheric compounds,” she says. “Alternatively, if the planet is sufficiently far away from its host star, we can also learn about a planet’s atmosphere by imaging it.”
However, significant portions of the population of extrasolar planets do not fit either of these criteria, and there was not really a way to find information about the atmospheres of these planets. Looking to resolve this problem, Lockwood and her adviser Geoffrey Blake, professor of cosmochemistry and planetary sciences and professor of chemistry, applied a novel technique for finding water in a planetary atmosphere. Other researchers had used similar approaches previously to detect carbon monoxide in tau Boötis b.