The Chemical Composition of the Exoplanet WASP-39b and Its Detection with the US$10-billion Telescope
The carbon/oxygen ratio of an exoplanet’s atmosphere is a telltale sign of where the planet formed6. Since the first exoplanet was found, the formation mechanism of giant planets that are close to their host stars has been an open question. The ratio measured for WASP-39b indicates that the planet might have formed at a location beyond the system’s water-ice line — the distance from the host star at which it is cold enough for compounds such as water and carbon dioxide to condense into solid ice. At this location, the planet could have moved into its current position through accretion of the oxygen-rich solid particles measured by the JWST.
A preliminary look at the atmospheres on these planets doesn’t provide a clue about what kind of atmosphere they might actually have. But if they have dense atmospheres with intriguing molecules such as carbon dioxide or methane, the US$10-billion telescope will be able to detect them in the coming months and years. These atmospheres have no other observatory that can spot them.
The telescope, launched in December 2021, observed the planet for more than 40 hours in July. Initial results showed carbon dioxide in the planet’s atmosphere. It was the first time that the gas had been seen on an exoplanet.
The astronomer at the University of Chicago said that the chemistry of planets outside the solar system is important because it is an important process here on Earth. Until now, “we’ve only been able to test our understanding of photochemistry in our Solar System. We can get access to completely different physical conditions on planets around other stars.
It is predicted that the inward migration of hot Jupiters will explain their proximity to their stars. This is uncertain if the process is a slow one over many millions of years, or if it was a result of a star hitting another planet. Analyzing WASP 39b’s composition could help determine which scenario occurred.
The planet is tidally locked to its star, with the same face always pointing towards it, because of the immense gravitational attraction between them. And the observations show that it has incomplete cloud cover — something that astronomers have never observed before on an exoplanet. At night and day, only about 60% of the planet is covered by clouds, says Bean, because they evaporate when they reach the hotter side.
First Results from JWST: What Have We Learned About the TRAPPIST-1 planets? A Comment on Björn Benneke
“We’re in business,” Björn Benneke, an astronomer at the University of Montreal, said during a symposium on first results from JWST in Baltimore, Maryland, on 13 December.
Another observation of TRAPPIST-1 planets was taken last week but she hadn’t had time to look at the results yet. “It’s hectic,” she says.
Benneke shared the first studies of TRAPPIST-1g. So far, the telescope has been able to make out that it probably doesn’t have a hydrogen-rich atmosphere — which would be relatively easy to spot because it is so physically large. It could mean that the planet is made of heavier compounds such as carbon dioxide, or no atmosphere at all.
According to Knicole Coln, an astronomer not involved in the work, it was important for them to know what they were dealing with. Benneke declined to speak with reporters about the TRAPPIST-1g results, citing a paper under review at a scientific journal.
A Comparison of Near Infrared Spectrograph and Camera Configurations for Observations of Exoplanetary Surfaces with the JWST Detector
Much work remains to be done to probe the limits of this habitability. A step towards understanding how photo chemistry protects exoplanetary surfaces from high energy irradiation is what the finding is about. It makes it harder for models of planetary formation to use parameters. Both advances pave the way to future observations of planets that are similar to Earth.
The wavelength ranges of the instruments used in the studies are within the range in which one can expect to find some of the atmospheric Molecules reported. But each instrument has different configurations that enable access to different wavelength ranges and spectral resolving powers. Rustamkulov and Alderson are associated with the same company. and Ahrer et al.4 used two configurations of an instrument called the Near Infrared Spectrograph; Feinstein et al. used the Near Infrared Imager and Slitless Spectrograph; and Ahrer et al.5 used a device known as the Near Infrared Camera. The teams were able to observe light with wavelengths of up to 5.5 micrometres.
Each instrument used various data-processing algorithms to navigate from raw data to the final spectrum. And although these efforts returned mostly similar results, the diverse approaches show that there is no consensus yet on the optimal way to process JWST data — indeed, there is much still to learn. Issues such as how to manage saturated and unreliable signals, and how to deal with mirror segments spontaneously tilt, have begun being addressed in the initial studies.