LHS 1140b is a rocky exoplanet located
about 48–49 light-years away in the constellation Cetus
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LHS 1140b is a rocky
exoplanet located about 48–49 light-years away in the constellation Cetus.
¨
It has a mass of 5.6
times that of Earth and a radius of 1.73 times Earth's radius.
¨
Scientists have detected
helium escaping from its atmosphere, providing evidence that the planet has an
atmosphere.
¨
LHS 1140b is one of the
few rocky, temperate exoplanets with observational evidence of an atmosphere in
the habitable zone.
¨
The planet is classified
as a Super-Earth, meaning it is larger than Earth but smaller than ice giants
like Neptune.
¨
It orbits a red dwarf
star.
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Being in the habitable
zone means conditions may allow liquid water to exist on its surface if the
atmosphere is suitable.
¨
Helium was detected using
the Warm Infrared Echelle Spectrograph (WINERED) on the Magellan Clay Telescope
at Las Campanas Observatory, Chile.
¨
Helium is used as an
indicator of atmospheric escape because it absorbs infrared light at specific
wavelengths in the upper atmosphere.
¨
Observations in 2024
detected a clear helium signal from LHS 1140b.
¨
Observations in 2025 did
not detect escaping helium, indicating that atmospheric escape can vary over
time.
¨
The presence of helium
suggests a helium-rich upper atmosphere, while models indicate that heavier
gases, including water vapour, may exist at lower altitudes.
¨
The habitable zone is the
region around a star where a planet can maintain liquid water under suitable
atmospheric conditions.
¨
LHS 1140b has likely
retained its atmosphere for at least 3.1 billion years, making it an important
target for astrobiology research.
¨
LHS 1140c, another rocky
planet in the same planetary system, orbits closer to the star and receives
about five times more radiation than LHS 1140b.
¨
No atmosphere has been
detected on LHS 1140c.
