Helium Gas Escaping Exoplanet LHS 1140b
Astronomers have detected helium gas escaping from the atmosphere of LHS 1140b, a potentially rocky exoplanet orbiting a red dwarf star in the constellation of Cetus, according to reporting by earthsky.org and theconversation.com. The finding offers a tentative glimpse at a long-lasting secondary atmosphere on a world situated within its star’s habitable zone.
Orbiting a Faint Red Dwarf Star
LHS 1140b orbits a faint red dwarf star located in the constellation of Cetus, near the “W” of Cassiopeia. earthsky.org reported that the star appears about 10,000 times fainter than the feeblest star visible to the unaided human eye and possesses roughly one-fifth the mass of our sun. As viewed from Earth, the host star dims with a regular brightness dip every 24.7 days.
Primary Versus Secondary Atmospheres
Previous observations using the James Webb Space Telescope ruled out a hydrogen-rich primary atmosphere on LHS 1140b, according to theconversation.com. Scientists believe rocky planets rapidly lose these initial primary envelopes soon after formation. The newly detected helium suggests the presence of a stable, long-lasting secondary atmosphere akin to Earth’s billions-of-years-old gas envelope.
Super-Earth or Mini-Neptune Classification
Estimates of the exoplanet’s physical dimensions vary based on observational data. Initial calculations following its 2017 discovery estimated LHS 1140b to be 1.7 times larger than Earth, while subsequent observations indicated it is just over five times bigger than Earth, earthsky.org reported. This leaves astronomers uncertain whether to classify the body as a super-Earth or a mini-Neptune due to a lack of close-range planetary examples.
LHS 1140b Temperatures May Range from -30 to -90 C
Positioned within the habitable zone of its host star, LHS 1140b presents surface temperature calculations that depend heavily on mathematical modeling. If the planet absorbs all incoming stellar radiation, it would maintain an equilibrium temperature of -30 C (-22 F), which could allow liquid water under a thick greenhouse atmosphere, according to theconversation.com. However, more realistic mathematical treatments suggest temperatures could plunge to -90 C (-130 F), a harsh climate comparable to present-day Mars.
Astronomers Struggle to Replicate Atmospheric Detections
The evidence supporting the exoplanet’s atmosphere remains tentative. This marks only the second time astronomers have captured hints of an atmosphere around a remotely Earthlike exoplanet, following previous observations of Gliese 1214b, earthsky.org noted. Complicating the findings, a second observation conducted within the study failed to detect helium, and researchers remain unsure why the subsequent data did not replicate the initial detection.
Frequently Asked Questions About LHS 1140b
What instrument was used to rule out a primary atmosphere?
Astronomers used the James Webb Space Telescope to rule out the existence of a hydrogen-rich primary atmosphere on LHS 1140b, according to theconversation.com.
How often does LHS 1140b transit its host star?
The host star dims with a regular brightness dip every 24.7 days as the planet passes across its face, earthsky.org reported.