Many exoplanets have opaque atmospheres, obscured by clouds or hazes that make it hard for astronomers to characterize their chemical compositions.
Many exoplanets have opaque atmospheres, obscured by clouds or hazes that make it hard for astronomers to characterize their chemical compositions. A new study shows that haze particles produced under different conditions have a wide range of properties that can determine how clear or hazy a planet’s atmosphere is likely to be.
Photochemical reactions in the atmospheres of temperate exoplanets lead to the formation of small organic haze particles. Large amounts of these photochemical hazes form in Earth’s atmosphere every day, yet our planet has relatively clear skies. The reason has to do with how easily haze particles are removed from the atmosphere by deposition processes.
“It’s not just haze production but also haze removal that determines how clear the atmosphere is,” said Xinting Yu, a postdoctoral fellow at UC Santa Cruz and lead author of the study, published July 12 in Nature Astronomy.
Yu and her colleagues measured the properties of haze particles produced in the laboratory under conditions representative of exoplanet atmospheres, including a range of gas compositions, temperatures, and energy sources. Coauthor Xi Zhang, assistant professor of Earth and planetary sciences at UC Santa Cruz, said laboratory experiments like this are essential for understanding haze formation and its impact on observations.
Read more at University of California - Santa Cruz
Image: Xinting Yu, a 51 Pegasi b Postdoctoral Fellow at UCSC, measured the properties of haze particles produced in the laboratory under conditions representative of exoplanet atmospheres. (Credit: Photo courtesy of Heising-Simons Foundation)