New study shows planet formation might be more complicated than previously thought
The natal disk of PDS 70 with new planet PDS 70b (bright spot on the right). By studying this system, researchers uncovered a mismatched composition of gases in the planet’s atmosphere compared to gases within the disk. Image by ESO/A. Müller et al.
Just as some children physically resemble their parents, many scientists have long thought that developing planets should resemble the swirling disk of gas and dust that births them.
But, in a new study, a Northwestern University-led team of astrophysicists discovered the resemblance might be looser than previously thought. By studying a still-forming exoplanet and its surrounding natal disk, the researchers uncovered a mismatched composition of gases in the planet’s atmosphere compared to gases within the disk.
The surprising finding potentially confirms long-held skepticism that scientists’ current model of planet formation is too simplified.
The study will be published today (Dec. 18) in the Astrophysical Journal Letters. It marks the first time physicists have compared information from an exoplanet, its natal disk and host star.
“For observational astrophysicists, one widely accepted picture of planet formation was likely too simplified,” said Northwestern’s Chih-Chun “Dino” Hsu, who led the study. “According to that simplified picture, the ratio of carbon and oxygen gases in a planet’s atmosphere should match the ratio of carbon and oxygen gases in its natal disk — assuming the planet accretes materials through gases in its disk. Instead, we found a planet with a carbon and oxygen ratio that is much lower compared to its disk. Now, we can confirm suspicions that the picture of planet formation was too simplified.”
Hsu is a postdoctoral associate at the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). He is advised by Jason Wang, an assistant professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences and member of CIERA.
Continue to the full Northwestern news article.