How close can a rocky planet be to a star and still support water and life? A recently discovered exoplanet could be the key to solving this mystery. “Super-Earth” LP 890-9c, also known as SPECULOOS-2c, provides valuable information about conditions at the inner edge of the star’s habitable zone and explains the opposite evolution of Earth and Venus. The research was led by Lisa Kaltenegger, a professor of astronomy at Cornell University.

His team found that LP 890-9c, orbiting near the inner rim of the solar system’s habitable zone, will look significantly different depending on whether it still has warm oceans, a steamy atmosphere, or has lost water—assuming it once did. Oceans like Earth.

“By looking at this planet, we’ll be able to understand what’s going on at this inner end of the habitable zone — how long a rocky planet can remain viable once it starts to warm,” Kaltenegger said. “This will teach us something fundamental about how rocky planets evolve with increased starlight and what will happen to us and Earth someday.”

Kaltenegger, Hot Earth or Young Venus? is the lead author of the book. The Mystery of the Recently Passing Rocky Planet”, published Monthly Notices of the Royal Astronomical Society: Letters.

Last year, researchers announced that LP 890-9c is one of two super-Earths orbiting a red dwarf star 100 light-years from Earth. (NASA’s Transiting Exoplanet Survey Satellite previously identified LP 890-9b.) LP 890-9c, which is about 40% larger than Earth and orbits in a small, cool orbit, contains a liquid water or water vapor-rich atmosphere. They said atmosphere is possible. stars in 8.5 days.

These criteria make it one of the best targets for studying JWST among known potentially habitable terrestrial planets in addition to the TRAPPIST-1 system.

The team’s models are the first to detail differences in chemical signatures produced by rocky planets near the inner boundary of the habitable zone, based on variables such as planet size, mass, chemical composition, surface temperature and pressure, atmospheric altitude and cloud cover. Calculations were key to estimating how long it would take for the JWST, if any, to verify the atmosphere’s elemental composition.

The models cover a variety of scenarios, thought to represent stages of evolution of rocky planets, ranging from a “warm Earth” where life could still exist, to a barren Venus with an atmosphere of carbon dioxide. In between, there are phases expected on Earth as the sun gets brighter and hotter as it ages, causing the oceans to slowly evaporate and fill the atmosphere with steam before it completely boils.

How long these processes might take is unknown, and astronomers say LP 890-9c offers a rare opportunity to study this evolution.

“This planet is the first target where we can test these different scenarios,” Kaltenegger said. “If Earth is still warmer—hot but with liquid water and living conditions in it—then the timeline is slower than we thought. If we see that there’s already a full-scale Venus, the water disappears quickly.”

It’s possible that LP 890-9c has no atmosphere and no life, or resembles Venus, with thick clouds that block the reflection of light and therefore provide little information. A deeper investigation promises to yield valuable clues, Kaltenegger said.

“We don’t know what this habitable planet might be like, so we have to look,” he said. “That’s what real research is about.” Source