A near-Earth exoplanet ‘offers us a glimpse into Earth’s possible future’

Exoplanet LP 890-9c is exciting for research because liquid water could exist there. The research team wants to examine it more closely.

Ithaca – There are distinct differences between the different rocky planets, which can be clearly seen in our solar system. An example of this is Venus and Earth, which, although similar in reality, have developed in completely different ways. Venus today is a hot “hell” with a closed cloud cover consisting mostly of sulfuric acid and with a surface pressure 90 times that of Earth’s. Due to the strong greenhouse effect, the planet is uninhabitable. In contrast, water covers the Earth about 75 percent and provides comfortable temperatures. It is habitable and hosts a variety of life.

What are the factors that led to the evolution of the two different rocky planets? This mystery is the concern of a research team led by Austrian astronomer Lisa Kaltenegger, who works at Cornell University in Ithaca (USA). The team has discovered an interesting celestial body that’s perfect for exploring this question: exoplanet LP 890-9c, tracked in 2022 by a research team that included Kaltenegger. About 40 percent larger in diameter than Earth (which makes it called a “super-Earth”), it is about 105 light-years away and orbits its star in just 8.5 days.

Exoplanet LP 890-9c: It may have liquid water on its surface

When an exoplanet was discovered, it was hypothesized to have water on its surface. Although the planet orbits its star at a short distance, it still receives a small amount of stellar radiation. This could open up the possibility of liquid water on the surface if an atmosphere were present. In the study published by the research team led by Kaltenegger, the in the journal Monthly Notices of the Royal Astronomical Society: Letters Backasserts that this exoplanet is “a key to how Venus and Earth evolved very differently.”

“In the inner part of the habitable zone, we expect hot, habitable planets. But when does it get too hot? We have models that predict how close a planet will be to its star before it gets too hot. But we’ve never observed such planets,” Kaltenegger explains. On request by FR.de from IPPEN.MEDIA. This is why exoplanet LP 890-9c is so exciting: It lies right on the border of the habitable zone – the region around a star in which liquid water might be possible on a planet’s surface.

What happens at the inner edge of the habitable zone?

For the study, the research team created seven different atmospheric models for LP 890-9c. Kaltenegger explains the study’s approach in one: “Looking at this planet will show us what happens at the inner edge of the habitable zone — how long a rocky planet can remain habitable once it starts to rise.” University press release. “It will teach us something fundamental about how rocky planets evolve as starlight increases and what will one day happen to us and our Earth.”

The Austrian astronomer’s discovery has to do with the fact that the Sun will get brighter and brighter over time until, in about 500 to 800 million years, the Earth becomes so hot that the oceans evaporate. “This is exactly where the LP 890-9c’s notes get exciting,” explains Kaltenegger. If the exoplanet is indeed an “uninhabitable planet,” it could be faster than expected and only have 500 million years left. On the other hand, if the exoplanet is still a living, hot Earth, then there is more time left on our Earth. “Because this planet gets – relatively speaking – more light from its star than we do from the Sun, it gives us a glimpse into a possible future.”

James Webb Space Telescope for Exoplanet Study LP 890-9c

In another study also published in the journal Monthly Notices of the Royal Astronomical Society: Letters published, Caltenegger and Jonathan Gomez-Barrientos of Caltech investigate the possibility and how the James Webb Space Telescope (JWST) will study the exoplanet LP 890-9c. “Professor Kaltenegger and I thought this exoplanet could be an excellent target for a JWST,” says Barrientos. The study showed that the new space telescope is able to confirm the presence of a possible atmosphere.

“Using the James Webb Space Telescope, for the first time we have a telescope large enough to study rocky planets and see if LP 890-9c is still a living, hot Earth or a planet where all the water has evaporated and is still trapped in the atmosphere – or the planet has already lost all of its water and has become Venus We often learn the most new things within our understanding, ”Kaltenegger emphasizes. Therefore, the astronomer also wants to try to obtain the time of the JWST observation of an exoplanet.

Does the outer planet have an atmosphere and what is it made of?

If the Earth telescope spots an exoplanet three times as it passes in front of its star (a so-called transit), the telescope can already show whether its atmosphere is largely composed of water vapor. After eight transits, JWST can detect Venus’s like atmosphere, and after 20 transits, the telescope can also find evidence of a possible hot but habitable Earth scenario, the research team noted.

In spite of everything, there is also the possibility that the exoplanet LP 890-9c has no atmosphere and no life on it. It might even resemble Venus, with thick clouds that cause a greenhouse effect and allow little information to leak out. “We don’t know how this planet could be on the brink of habitability, so we have to look,” Kaltenegger asserts. “That’s what the real research is about.”

Machine assistance was used in this editorial article. The article was carefully checked by the editor, Romina Kunz, before it was published.