NASA Spitzer Telescope Locates First Planet Without Atmosphere Orbiting Red Dwarf
- by Carmen Reese
- in Science
- — Aug 23, 2019
The planet is described as "overheated" by NASA, which notes that LTT 1445 A b is about 1.4 times the size of Earth.
The planet's only 1.3 times bigger than Earth and orbits a dim star which is close enough to warm up.
"We've got lots of theories about how planetary atmospheres fare around M dwarfs, but we haven't been able to study them empirically", said Laura Kreidberg, a researcher at the Harvard-Smithsonian Center for Astrophysics (CfA) and lead author of the new study, in the press release.
A distant rocky exoplanet has gone one better than Tatooine, Luke Skywalker's home planet on "Star Wars", which is famously depicted as having two suns in its sky. But the observations that were conducted with the telescope "Spitzer", showed that it is likely completely missing the atmosphere. An exciting aspect of LHS 3844b is that its orbit around its sun takes only 11 hours, which is quite fast even for it. The star-facing side, or dayside, is about 1,410 degrees Fahrenheit (770 degrees Celsius).
Dubbed LHS 3844b, the planet has no atmosphere but holds to key to understanding where scientists should be looking for signs on life beyond Earth. The planet's surface may be covered mostly in dark lava rock, with no apparent atmosphere, according to observations by NASA's Spitzer Space Telescope.
Because there's no atmosphere - meaning no winds, no air and no movement - none of that heat gets dispersed around the planet and both sides continue to exhibit temperatures that are poles apart.
The Earth's atmosphere supports life - but not every planet has the same protective layer around it.
The fact that LHS 3844b doesn't have an atmosphere makes it more like the Moon and Mercury rather than the Earth.
The study is likely to add to a debate among astronomers about whether the search for life-sustaining conditions beyond our solar system should focus on exoplanets around red dwarfs - accounting for 75% of all stars in the Milky Way - or less common, larger, hotter stars more like our own sun.
This planet is outside our solar system and has been strategically important to figure out the atmosphere in such planets. (Measured in units called bars, Earth's atmospheric pressure at sea level is about 1 bar.) An atmosphere between 1 and 10 bars on LHS 3844b has been nearly entirely ruled out as well, although the authors note there's a slim chance it could exist if the stellar and planetary properties were to meet some very specific and unlikely criteria.
Although the M-dwarf star that the planet is orbiting is cool in temperature compared with other stars, it unleashes flares of ultraviolet light that can destroy a planetary atmosphere. Using the data of NASA's Spitzer Space Telescope, scientists have detected the light from the planet LHS 3844b, which is located 48.6 lightyears away from the Earth.
The alien exoplanet orbits a small, cool type of star called an M dwarf.
"We know that the mare of the moon are formed by ancient volcanism", Renyu Hu, co-author of the study and an exoplanet scientist at NASA's Jet Propulsion Laboratory, said in the press release.