Science
Related: About this forumThe First Ultra-Hot Neptune Has Carbon Monoxide In Its Atmosphere
ARTIST'S IMPRESSION OF LTT9779B TRANSITING ITS STAR. ETHEN SCHMIDT/KANSAS UNIVERSITY
Alfredo Carpineti
By Alfredo Carpineti
26 OCT 2020, 18:40
In the last few decades, a peculiar distribution of exoplanets has appeared in astronomers' data: planets that are close to their stars are either really big like Jupiter or small like Earth. Neptune-sized worlds in this region are rare.
To learn more, a study recently published in The Astrophysical Journal Letters reports on the atmospheric composition of one of these hot Neptunes, as they are known. Planet LTT9779 b is so close to its star that it has a day-side temperature of over 2,000°C (3,660°F), making it the first entry in the ultra-hot Neptune category.
The research suggests the planet is tidally locked, with one side in perennial light and the other in constant darkness. Astronomers also caught the planet crossing the face of its star, which allowed them to catch a glimpse of the atmosphere and discover the presence of carbon monoxide.
"For the first time, we measured light coming from a planet that shouldn't exist! This ultra-hot Neptune is a 'medium-sized' exoplanet that orbits very close to its star (it takes just 19 hours to complete an orbit), but its low density indicates that it still has an atmosphere weighing at least 10 percent of the planet's mass," lead author Diana Dragomir, an assistant professor from the University of New Mexico, said in a statement.
More:
https://www.iflscience.com/space/the-first-ultrahot-neptune-has-carbon-monoxide-in-its-atmosphere/
Judi Lynn
(160,218 posts)MICHELLE STARR27 OCTOBER 2020
The discovery of the extraordinary exoplanet LTT 9779b was first announced a month ago. Just 260 light-years away, the planet was immediately pegged as an excellent candidate for follow-up study of its curious atmosphere. But it turns out we didn't even have to wait too long to learn more.
LTT 9779b is a little bigger than Neptune, orbiting a Sun-like star - fairly normal so far. But two things are really peculiar. It's so close to its star, the planet orbits once every 19 hours; and, in spite of the scorching heat it must be subjected to at that proximity, LTT 9779b still has a substantial atmosphere.
Infrared observations collected by the now-retired Spitzer Space Telescope included the planet's host star, and astronomers have now analysed those data, publishing their results in a couple of studies.
In the first paper, a team led by astronomer Ian Crossfield of the University of Kansas has described LTT 9779b's temperature profile.
More:
https://www.sciencealert.com/astronomers-peer-into-the-atmosphere-of-a-rare-exoplanet-that-shouldn-t-exist