Here on Earth, when we look up we see a beautiful blue sky. Now imagine seeing nothing but a yellow sky. Well, that’s exactly what you would witness if you lived on WASP-79b.
The huge gas exoplanet is located approximately 780 light-years away from us and it’s so close to its host star that it completes an orbit in just 3.7 Earth days. And saying that it’s exceptionally hot is an understatement as the average temperature on WASP-79b is about 3,000 degrees Fahrenheit (or 1,650 degrees Celsius). The extreme temperatures makes it swell up, making it one of the biggest exoplanets ever discovered. For comparison, while it is 85% as massive as Jupiter, it is 1.7 times wider.
It is also more than likely tidally locked to its host star, meaning that it continuously shows the same side of the planet. In addition to yellow skies and extreme temperatures, signs of water vapor in the atmosphere were discovered by NASA’s Hubble Space Telescope. A recent study has claimed that it probably rains iron on the planet.
By studying the planet’s atmosphere by using the Hubble as well as the Magellan Consortium’s Magellan II Telescope in Chile, scientists were surprised to find out that there no indications of “Rayleigh scattering” which is when tiny dust particles in high altitude create wavelengths of starlight that scatter differently.
Lead author Kristin Sotzen, who is a graduate student in the Department of Earth and Planetary Sciences at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, explained this further, “This is a strong indication of an unknown atmospheric process that we’re just not accounting for in our physical models. I’ve shown the WASP-79b spectrum to a number of colleagues, and their consensus is ‘that’s weird.’”
She went on to say, “Because this is the first time we’ve seen this, we’re really not sure what the cause is,” adding, “We need to keep an eye out for other planets like this because it could be indicative of unknown atmospheric processes that we don’t currently understand. Because we only have one planet as an example, we don’t know if it’s an atmospheric phenomenon linked to the evolution of the planet.” (The study was published in The Astronomical Journal and can be read here.)
Scientists are planning further studies of WASP-79b with the James Webb Space Telescope which is scheduled to be launched into space next year. It will analyze some of the earliest stars and galaxies in the universe as well as study exoplanets for potential signs of life. Although with temperatures at a scorching hot 3,000 degrees Fahrenheit, it’s safe to assume that nothing could survive on WASP-79b. I guess nobody will be able to enjoy the yellowish alien skies…