Yeah, yeah, the Sun is good. We get it. A whole 864,000 miles wide, 27 million degrees Fahrenheit. Giver of life, and feel-goods like “Here Comes the Sun.” So what? After literally seeing inside our great star’s atmosphere, the honey-sun phase is over. We’re eager to explore other spheres of hot plasma, which is why NASA’s most recent discovery of three new worlds orbiting a small star is so damn exciting.
Wellllll, it’s more exciting because the discovery allows for atmospheric study, and because NASA’s newest planet hunter, the Transiting Exoplanet Survey Satellite (TESS), was the one to find the planetary system.
“This system is exactly what TESS was designed to find -- small, temperate planets that pass, or transit, in front of an inactive host star, one lacking excessive stellar activity, such as flares,” said lead researcher Maximilian Günther in a press release. “This star is quiet and very close to us, and therefore much brighter than the host stars of comparable systems. With extended follow-up observations, we’ll soon be able to determine the make-up of these worlds, establish if atmospheres are present and what gases they contain, and more."
TOI 270 is a dwarf star about 40% smaller and one-third cooler than the Sun. The innermost planet, TOI 270 b, is likely a rocky one that beats Earth in size by 25%. Its surface temperature is around 490 degrees Fahrenheit, though. And no swimming pools.
TOI 270 c and d are both over two times larger than Earth and resemble Neptune in gassy composition and mass. So, also no pools. However, these two planets are smaller than Neptune. NASA describes them as "mini-Neptunes" and said they're a type of planet not found in our solar system. That, of course, makes them extra fascinating.
"An interesting aspect of this system is that its planets straddle a well-established gap in known planetary sizes,” Fran Pozuelos, a postdoctoral researcher at the University of Liège in Belgium, said in statement. “It is uncommon for planets to have sizes between 1.5 and two times that of Earth for reasons likely related to the way planets form, but this is still a highly controversial topic. TOI 270 is an excellent laboratory for studying the margins of this gap and will help us better understand how planetary systems form and evolve.”
The whole system is located 73 light-years away, in the constellation of Pictor. Have I lost you? Just know that we won’t be traveling there when the Earth falls apart, but it’s still a cool thing to study.
Adina Feinstein, another co-author of the paper published on the system, says TOI 270’s position in the sky is perfect for studying the Neptune-like planets with the James Webb Space Telescope. Our whole new worlds will be observable for over six months.