User:117daveawesome/sandbox/LTT 1445 Ab

LTT 1445 Ab

Discovery
Discovery date	2019
Detection method	Transit
Orbital characteristics
Semi-major axis	0.022
Orbital period (sidereal)	5.4 d
Star	LTT 1445 A
Physical characteristics
Mean radius	1.18 R🜨
Mass	2.87 ME

LTT 1445 Ab is an exoplanet that was discovered in 2019. The planet is located about 22 light years away from Earth and takes 5 days to orbit its star, which in turn orbits two sibling stars, making a total of three stars in the system.

Discovery

This superheated planet, about 1.4 times the size of Earth, has a sky one fortress bigger than Star Wars' Tatooine -- three stars instead of two. It was found by a team at the Harvard Center for Astrophysics using data from the TESS space telescope on July 26, 2019.

Key facts

LTT 1445 Ab, apparently a rocky planet, takes only five days to orbit its star —a "year" on this world, which is about 22.5 light-years from Earth. Its extremely close orbit helps explain why its surface heats to temperatures on the order of 320 degrees Fahrenheit (160 Celsius), comparable to a preheated oven.

Details

While the planet itself remains in a presumably stable orbit around its star, that star also orbits at greater distances around two sister stars that are locked in close orbit around each other. This is not the first triple star system to contain at least one planet. In fact, our nearest stellar neighbor is Proxima Centauri, which orbits a more distant pair, Alpha Centauri A and B. Proxima Centauri is only 4.25 light-years from Earth. It is orbited by Proxima Centauri b, a small, possibly rocky world estimated to take 11 days to orbit its star. According to the TESS data, scientists believe the planet is rocky, about a third larger than Earth, and at most about 8 times more massive than Earth.

Interesting facts

All three stars in the LTT 1445 system are red dwarfs, which are cooler and burn much longer than large yellow stars like our Sun. This planet is also the second-closest known planet to "pass" its star—that is, LTT 1445 Ab's orbit is tilted at just the right angle to pass across its star from our perspective. The "transit" observing method allows space telescopes like TESS to detect planets orbiting other stars by the shadows they cast, the tiny dip in starlight as the planet transits.

The closest transiting planetary system discovered so far is HD 219134 bc, which is about 21 light-years away.

"If you're standing on the surface of this planet, there are three suns in the sky, but two of them are pretty far away and look small," co-author Jennifer Winters, an astronomer at the Harvard-Smithsonian Center for Astrophysics, told New Scientist. "They are like two red ominous eyes in the sky."

Possible atmosphere

But what is particularly special about it is something that scientists cannot yet characterize, but will soon be able to characterize: its atmosphere. Because the stars in question are red dwarfs that are quite close to Earth, and because the system is arranged so that the planet passes between the stars and Earth, scientists may actually be able to see any gases surrounding the planet with telescopes on earth.

In 2022, a planetary transmission spectrum has showed no evidence for the atmosphere, although atmosphere with high altitude hazes cannot be ruled out yet.