What can carbon dioxide in an exoplanet’s atmosphere teach us about its formation and evolution? This is what a recent study published in The Astrophysical Journal hopes to address as an international team of researchers made the first direct images of carbon dioxide in the atmospheres of two exoplanetary systems. This study has the potential to help researchers better understand the formation and evolution of exoplanet atmospheres and how this could lead to finding life as we know it, or even as we don’t know it.
For the study, the researchers used NASA’s James Webb Space Telescope (JWST) to analyze the atmospheres of exoplanets residing in the systems HR 8799 and 51 Eridani (51 Eri) with the direct imaging method. The HR 8799 system is located approximately 135 light-years from Earth and hosts four known exoplanets whose masses range from five to nine times of Jupiter, and the 51 Eridani system is located approximately 97 light-years from Earth and hosts one known exoplanet whose mass is approximately four times of Jupiter. Both systems are very young compared to our solar system at approximately 4.6 billion years old, with HR 8799 and 51 Eridani being approximately 30 million and 23 million years old, respectively.
JWST direct image of the HR 8799 system, which is the clearest direct image in infrared ever taken of an exolpanet system. (Credit: NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI))
After comparing the findings with models used to predict their atmospheric compositions, the researchers found that the planets orbiting in both systems contain higher-than-anticipated levels of carbon dioxide in their atmospheres, suggesting they are high in metallic content. Additionally, the researchers were able to obtain precise eccentricity measurements for 51 Eri b, which is approximately 0.57. For context, Earth’s eccentricity is 0.0167, meaning it’s almost perfectly circular, while 51 Eri b’s eccentricity is more oval-shaped. The researchers concluded that this means the 51 Eri system experienced a chaotic formation in its past.
JWST direct image of the 51 Eridani system. (Credit: NASA, ESA, CSA, STScI, W. Balmer (JHU), L. Pueyo (STScI), M. Perrin (STScI))
“Our hope with this kind of research is to understand our own solar system, life, and ourselves in comparison to other exoplanetary systems, so we can contextualize our existence,” said William Balmer, who is a PhD Candidate in the Department of Physics and Astronomy at the Johns Hopkins University and lead author of the study. “We want to take pictures of other solar systems and see how they’re similar or different when compared to ours. From there, we can try to get a sense of how weird our solar system really is—or how normal.”
Going forward, the team aspires to duplicate this study for other exoplanet atmospheres using JWST to compare findings to longstanding models.
What new discoveries regarding carbon dioxide and exoplanet atmospheres will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: The Astrophysical Journal, Wikipedia, Wikipedia (1), EurekAlert!