Astronomers Develop Method to Detect Oxygen on Faraway Planets

(CN) – Scientists announced Monday a new method of detecting oxygen in distant planets that could help in the search for extraterrestrial life.

In a work published in the journal Nature Astronomy, a team of research scientists from NASA and the University of California, Riverside, said they developed a way to detect the signal that oxygen molecules create when they collide.

Conceptual image of water-bearing (left) and dry (right) exoplanets with oxygen-rich atmospheres. Crescents are other planets in the system, and the red sphere is the M-dwarf star around which the exoplanets orbit. The dry exoplanet is closer to the star, so the star appears larger. (Image courtesy of NASA)

Using the James Webb Space Telescope to detect the presence of oxygen could help scientists determine living and nonliving planets beyond our solar system. The presence of oxygen is a possible indication of life, such as oxygen produced by plants and algae on Earth.

“Before our work, oxygen at similar levels as on Earth was thought to be undetectable with Webb,” said Thomas Fauchez of NASA’s Goddard Space Flight Center and lead author of the study. “This oxygen signal is known since the early 1980s from Earth’s atmospheric studies but has never been studied for exoplanet research.”

Edward Schwieterman, astrobiologist at UC Riverside, first proposed a similar technique and was a member of this team.

“Oxygen is one of the most exciting molecules to detect because of its link with life, but we don’t know if life is the only cause of oxygen in an atmosphere,” Schwieterman said. “This technique will allow us to find oxygen in planets both living and dead.”

Oxygen molecules block parts of infrared light from being seen from a telescope when they collide with each other, according to the scientists. Using the patterns in the light, researchers can figure out how much oxygen is in a planet’s atmosphere.

The scientists cautioned that the presence of oxygen can make a distant planet appear to have life when it doesn’t.

“If an exoplanet is too close to its host star or receives too much star light, the atmosphere becomes very warm and saturated with water vapor from evaporating oceans,” they said in a statement. “This water could then be broken down by strong ultraviolet radiation into atomic hydrogen and oxygen. Hydrogen, which is a light atom, escapes to space very easily, leaving the oxygen behind.”

Using the new method, however, Schwieterman said scientists can discover how widespread the process may be and help narrow down potential life-hosting planets in the future.

“It is important to know whether and how much dead planets generate atmospheric oxygen, so that we can better recognize when a planet is alive or not,” he said.

The Webb telescope is set to launch in 2021.

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