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- LHS 3844 b is a super-Earth exoplanet<\/strong> 48.5 light-years from Earth. It\u2019s about 30% larger than our own Earth.<\/li>\n
- New observations by the James Webb Space Telescope<\/strong> show that LHS 3844 b is dark, scorching hot and has no atmosphere. Its year last less than half an Earth-day.<\/li>\n
- Its composition is also unlike Earth\u2019s,<\/strong> data shows. It likely resembles Mercury or the moon in composition and appearance.<\/li>\n<\/ul>\n
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Nearby super-Earth hot and airless<\/h3>\n
Using the James Webb Space Telescope, an international team of researchers has analyzed the surface of a nearby super-Earth type exoplanet, only 48.5 light-years away. They said on May 4, 2026, that this large rocky world is dark on its surface, extremely hot and airless. The planet is called LHS 3844 b.<\/em> <\/p>\n
The study suggests LHS 3844 b probably looks a lot like a larger version of our sun\u2019s innermost planet, Mercury, or Earth\u2019s large moon.<\/p>\n
But LHS 3844 b orbits much closer to its red dwarf star than Mercury does to our sun. It orbits just 0.006 AU from its star, in contrast to Mercury\u2019s much larger distance of 0.387 AU (1 AU = 1 Earth-sun distance). LHS 3844 b is classified as an ultra-short period planet<\/em>. So it \u201chugs\u201d its star tightly, so tightly that its entire year lasts less than half an Earth-day. Meanwhile, Mercury\u2019s year is 88 Earth-days long.<\/p>\n
In other words, if you lived on LHS 3844 b, you\u2019d celebrate your birthday twice every earthly day.<\/p>\n
Could we live there? Definitely not. It\u2019s too blazingly hot, with surface temps of about 725 degrees Celsius or 1,340 degrees Fahrenheit.<\/p>\n
But LHS 3844 is<\/em> a rocky world. So, assuming we could overcome the heat of its surface, we could stand on it. Its composition is largely basaltic instead of silicate. Silicate minerals are the most common and important class of rock-forming minerals on Earth, making up approximately 90% of the Earth\u2019s crust.<\/p>\n
Former PhD student Sebastian Zieba at Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany (now at the Center for Astrophysics | Harvard & Smithsonian in Cambridge) and Laura Kreidberg at MPIA led the new study.<\/p>\n
The researchers published their peer-reviewed findings in Nature Astronomy<\/em> on May 4, 2026. There is also a non-paywalled preprint version available on arXiv.<\/p>\n
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1\/3 ? Exciting discoveries from the James Webb Space Telescope! Researchers from MPIA and CfA | Harvard & Smithsonian analysed the rocky exoplanet LHS 3844 b, revealing a dark, hot surface likely composed of basalt. We are beginning to do #exogeology. ? #Exoplanets #JWSTwww.mpia.de\/news\/science\u2026<\/p>\n
\u2014 Max-Planck-Institut f\u00fcr Astronomie (@mpi-astro.bsky.social) 2026-05-04T19:06:32.622Z<\/p>\n<\/blockquote>\n
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The dark and featureless surface of rocky exoplanet LHS 3844 b from JWST mid-infrared spectroscopy. Sebastian Zieba et. al. <\/p>\n
\u2014 AstroArxiv (@astroarxiv.bsky.social) 2026-05-08T03:31:19.873Z<\/p>\n<\/blockquote>\n
A dark, scorched world<\/h3>\n
LHS 3844 b is what scientists call a super-Earth<\/em>. So it\u2019s about 30% larger than Earth. And it\u2019s also tidally-locked. This means it keeps the same side facing its star, much as our moon keeps a single side toward Earth. Both Earth\u2019s moon \u2013 and LHS 3844 b \u2013 take the same time to complete one orbit as to complete a single rotation. Voila. That\u2019s why they keep a single face turned toward their parent objects.<\/p>\n
But in LHS 3844 b\u2019s case, that object is a star. So this little world is exceedingly hot, especially on its star-facing side. Its surface \u2013 basically a dark gray color \u2013 is about 725 degrees Celsius or 1,340 degrees Fahrenheit.<\/p>\n
A larger version of Mercury or the moon<\/h3>\n
The researchers say this exoplanet likely resembles Mercury or our moon in appearance. The research team determined this by measuring the infrared radiation coming from the planet\u2019s scorched surface.<\/p>\n
Older data from the Spitzer Space Telescope a few years ago also supports this conclusion.<\/p>\n
And just like Mercury and the moon, it is an airless world, despite being larger than Earth.<\/p>\n
![\"Large](\"https:\/\/earthsky.org\/upl\/2023\/06\/c_lionel-super-Earth-mini-Neptune-TOI-2096-University-of-Liege-TESS-June-2023-e1685962356398.jpg\")
Artist\u2019s illustration of a super-Earth exoplanet close to its red dwarf star. Some super-Earths might have oceans while others, like LHS 3844 b, are hot, airless and barren. Image via C. Lionel\/ University of Li\u00e8ge. Used with permission.<\/figcaption><\/figure>\n Composition of LHS 3844 b<\/h3>\n
So apart from its appearance, what\u2019s the composition of LHS 3844 b? The analysis ruled out a composition similar to Earth. Unlike Earth\u2019s silicate composition, this planet\u2019s crust and\/or mantle is likely composed of basalt, perhaps similar to the moon.<\/p>\n
This also means the planet probably lacks plate tectonics. Zeba said:<\/p>\n
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Since LHS 3844 b lacks such a silicate crust, one may conclude that Earth-like plate tectonics does not apply to this planet, or it is ineffective. This planet likely only contains little water.<\/p>\n<\/blockquote>\n
The researchers performed a more detailed statistical analysis. This supported the conclusion that solid areas of basalt or magmatic rock best match the observations. These areas can also contain magnesium, iron and olivine. Crushed rocks and gravel on the surface are thought to be more likely than smaller grains or powders. As Zieba noted:<\/p>\n
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It turns out, these processes not only slowly dissolve hard rocks into regolith, a layer of fine grains or powder as found on the moon. They also darken the layer by adding iron and carbon, making the regolith\u2019s properties more consistent with the observations.<\/p>\n<\/blockquote>\n
![\"Smiling](\"https:\/\/earthsky.org\/upl\/2026\/05\/Sebastian-Zieba-Center-for-Astrophysics-Harvard-and-Smihsonian.jpg\")
Sebastian Zieba at the Center for Astrophysics | Harvard and Smihsonian is the lead author of the new study about LHS 3844 b. Image via Center for Astrophysics | Harvard and Smihsonian.<\/figcaption><\/figure>\n An active surface? Or not?<\/h3>\n
Basically, there are two main possible scenarios. The first is that the planet\u2019s surface is mostly dark, solid basaltic or magmatic rock. It is subject to relatively quick alteration by space weather. There might be volcanism involved in this relatively \u201cfresh\u201d surface.<\/p>\n
In the other scenario, the dark surface is even more like Mercury or the moon. But there are likely long periods of no geological activity, or maybe none at all.<\/p>\n
So which scenario is correct? We don\u2019t know for sure. But one clue is that Webb should have detected sulfur dioxide (SO2) if there was any volcanic activity. And it didn\u2019t. So as of now, the researchers are favoring the second scenario.<\/p>\n
The researchers now want additional observations by Webb. They want to examine differences in how solid slabs and powders emit or reflect light on the surface. That would help them further determine which of the two geological scenarios is the most likely. Kreidberg said:<\/p>\n
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We are confident the same technique will allow us to clarify the nature of LHS 3844 b\u2019s crust and, in the future, other rocky exoplanets.<\/p>\n<\/blockquote>\n
Bottom line: The Webb space telescope observed nearby super-Earth LHS 3844 b. It found it blazingly hot and airless, close to its star.<\/p>\n
Source: The dark and featureless surface of rocky exoplanet LHS 3844 b from JWST mid-infrared spectroscopy<\/p>\n
Source (preprint): The dark and featureless surface of rocky exoplanet LHS 3844 b from JWST mid-infrared spectroscopy<\/p>\n
Via Max Planck Institute for Astronomy<\/p>\n
Read more: Powerful magnetic fields on super-Earths could boost chances of life<\/p>\n
Read more: Super-Earths may have long-lasting oceans<\/p>\n
<\/div>\n
\n - New observations by the James Webb Space Telescope<\/strong> show that LHS 3844 b is dark, scorching hot and has no atmosphere. Its year last less than half an Earth-day.<\/li>\n