A new ‘dark’ planet on NASA’s radar might hold the key to what makes or breaks a planet

A new ‘dark’ planet on NASA’s radar might hold the key to what makes or breaks a planet
Artist's illustration of LHS 3844b, which is 1.3 times the mass of Earth and orbits an M dwarf starNASA
  • NASA's Spitzer Space Telescope has been observing a planet 48.6 light years away from Earth.
  • 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.
  • This is the first time that NASA has been able to observe a planet without an atmosphere that orbiting a red dwarf star.
The Spitzer Space Telescope has been observing a planet that’s 1.3 times larger than the Earth and 48.6 light years away. And, it completes its orbit in a mere 11 hours.

But, it has one critical flaw — no atmosphere.

The Earth’s atmosphere supports life — but not every planet has the same protective layer around it. It is especially true with planets that orbit small stars.

Officially named LHS 3844b, it is the first planet without an atmosphere orbiting a red dwarf star, to ever be observed by the National Aeronautics and Space Administration (NASA) after being spotted by the Transiting Exoplanet Satellite Survey (TESS) in 2018.

What breaks or makes a planet

The lack of an atmosphere around LHS 3844b may not be able to support life but it gives scientists some understanding around what kind of factors can make or break a planetary atmosphere — especially since we’re always on the hunt for habitable planets beyond our own Solar System.

"We've got lots of theories about how planetary atmospheres fare around M dwarfs, but we haven't been able to study them empirically," states Laura Kriedberg, a researcher at the Harvard and Smithsonian Center for Astrophysics and lead author of the study.

"Now, with LHS 3844b, we have a terrestrial planet outside our solar system where for the first time we can determine observationally that an atmosphere is not present," explains Kriedberg.

Volcano and ashes

Unlike most planets that are close to a star, LHS 3844b is actually ‘quite dark’, according to Renyu Hu, an exoplanet scientist with NASA and co-author of the study published in Nature.

Spitzer and NASA's Hubble Space Telescope have observed gas planets and their atmospheres in the past, but this is the first time that they’ve used light — or lack thereof — to gather data about a planet.

The fact that LHS 3844b doesn’t have an atmosphere makes it more like the Moon and Mercury rather than the Earth.

Even it’s surface is covered in volcanic residue similar to the material found on the lunar surface called mare.

Hot and cold

The similarities between LHS 3844b and the Moon don’t stop at both of them being covered in ancient volcanic ash. They both have a ‘dark side’ as well.

The Moon, in its orbit of Earth, always has one side that’s facing the planet and one side that’s permanently facing away.

The same ‘tidal lock’ has been observed on the planet where its ‘dayside’ heats up 770 degrees Celcius and the ‘night side’ never faces the star.

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.

Exceptional yet common

Red dwarves themselves aren’t uncommon as the smallest and the coolest of the star categories. In fact, they make up three quarters of the stars in the Milky Way.

Despite their abundance, they aren’t as easy to observe. Flickering at around 1/10,000 of the Sun’s brightness, most of them are invisible to the naked eye.

Because they’re so common, they’re also host to a majority of the planets in any particular galaxy, including our own. Understanding how they work and function is critical to figuring out where to look for life in the vast universe.

See also:
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