Exoplanet LHS 1140b Atmosphere Leaks Helium in Search for Alien Life
Astronomers detected helium gas escaping from the atmosphere of LHS 1140b, a potentially rocky exoplanet orbiting within the habitable zone of a faint red star in the constellation of Cetus. earthsky.org reported that this finding propelled the exoplanet into mainstream scientific and media discussions this summer, though a second observation failed to detect the leaking gas. The planet sits roughly 10,000 times fainter than the feeblest star visible to the unaided eye, yet its distance and characteristics make it a primary target in the ongoing search for worlds that could support liquid water and alien life.
Super-Earth Size and Red Dwarf Orbit Discrepancies
LHS 1140b orbits a red dwarf star that possesses about one-fifth the mass of our sun and shines roughly 300 times fainter. Telescopes record a regular brightness dip every 24.7 days as the planet crosses in front of its host star. Initial calculations by the discovery team in 2017 suggested the planet measured 1.7 times larger than Earth, while subsequent observations indicated a size just over five times bigger than Earth. This substantial size puts LHS 1140b in a classification gray area between a massive super-Earth and a compact mini-Neptune, leaving researchers uncertain about its exact internal composition because astronomers lack comparable sub-Neptunian examples inside our own solar system.
Primary Hydrogen Loss Versus Secondary Atmosphere Stability
James Webb Space Telescope observations previously ruled out a hydrogen-rich primary atmosphere around LHS 1140b, which aligns with theories that young rocky planets quickly shed their initial gaseous envelopes into space. The newly reported detection of escaping helium points instead toward a secondary atmosphere. Unlike transient primary gases, secondary atmospheres persist for billions of years, driven by planetary geology and chemistry. Earth maintains a stable secondary atmosphere that supports biological activity, giving astronomers reason to closely examine whether LHS 1140b retains a similar long-lasting gaseous shield.
Conflicting Helium Observations and Stellar Radiation Metrics
The debate over the planet’s atmospheric stability hinges on conflicting data from different observation windows. While the initial detection revealed helium actively bleeding off the planet into space, a subsequent follow-up observation recorded no trace of the gas. Furthermore, calculating the surface temperature of LHS 1140b depends heavily on how much stellar radiation it absorbs. If the exoplanet absorbs all incoming radiation from its parent red dwarf, planetary models indicate it would maintain an equilibrium temperature of minus 30 degrees Celsius, dropping well below the freezing point required for surface liquid water.
Frequently Asked Questions About LHS 1140b
How far away is LHS 1140b and which constellation hosts it?
LHS 1140b orbits a faint red star located within the constellation of Cetus, positioned right next to the recognizable W shape of Cassiopeia.
When was LHS 1140b first discovered by astronomers?
A team of astronomers discovered the exoplanet in 2017 by measuring the regular brightness dips of its host red dwarf star every 24.7 days.
What temperature range defines the habitable zone for this exoplanet?
The habitable zone theoretically allows for surface temperatures between 0 and 100 degrees Celsius, which could permit liquid water to exist on the planet’s surface.
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