Astronomers Found a Warm Rocky World That Could Support Oceans and Life

And it's very close to Earth.
Brad Bergan
An artist's impression of L 98-59-b.ESO / YouTube

Oceans of life may be more common than we thought.

When astronomers examined a nearby rocky world beyond our solar system they discovered conditions that may support vast oceans, brimming with life, according to a recent study published in the journal Astronomy & Astrophysics.

And we're just a few years away from potentially detecting biosignatures on an alien world.

A warm exoplanet might support vast oceans filled with life

Using the European Southern Observatory's Very Large Telescope (ESO's VLT), based in Chile, the team of astronomers discovered something exciting about planets orbiting a nearby star, called L 98-59. These planets are similar to those of our inner Solar System, and one of them is half the mass of Venus. The lightest exoplanet to be measured via the radial velocity technique, astronomers think it may also be a warm, ocean world, perfectly nested within its host star's habitable zone. "The planet in the habitable zone may have an atmosphere that could protect and support life," said Astronomer Maria Rosa Zapatero Osorio of the Center for Astrobiology in Madrid, Spain, who is also one of the study authors, in a press release from the observatory.

The new findings mark a historic step on the path to identifying life on Earth-like planets beyond our solar system, but there is still work to be done before we can definitively declare the existence of life out there. Scientists have to analyze the planet's atmosphere for biosignatures, and modern-day telescopes aren't large enough to provide the resolution needed to do this for small, rocky planets. But we can still mark the L98-59 system for future observations of exoplanet atmospheres. And if humanity survives that long, we definitely will: The star is only 35 light-years away, and hosts rocky planets, like Mars or Venus, which are neither too distant, nor too close to the star for life to form.

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We are just years away from potentially confirming life beyond our solar system

The team of researchers used the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) instrument, equipped on the ESO's VLT, to evaluate L 98-59. "Without the precision and stability provided by ESPRESSO this measurement would have not been possible," said Osorio, in the press release. "This is a step forward in our ability to measure the masses of the smallest planets beyond the solar system." L 98-59's planets were initially discovered in 2019 via NASA's Transiting Exoplanet Survey Satellite (TESS), which uses the transit method. This is when astronomers look for a "dip" in a star's light caused by a planet passing between us and it. And the way the light dips tells us a lot about the size of the planet, but it wasn't until radial velocity measurements recorded with ESPRESSO and its predecessor, the High Accuracy Radial velocity Planet Searcher (HARPS), which is an 11.8-ft (3.6-meter) telescope based at the ESO's La Silla, that the research team discovered even more planets, and measured the radii and masses of the first three planets.

"If we want to know what a planet is made of, the minimum that we need is its mass and its radius," said Olivier Demangeon, of the Instituto de Astrofísica e Ciências do Espaço, in the release. And the forthcoming James Webb Space Telescope from NASA, the ESA, and the CSA will bring us closer to confirming the existence of possible biosignatures on the star system's planets. This effort will also benefit from the ESO's Extremely Large Telescope (ELT), currently being built in the Atacama Desert, Chile, with observations slated to being in 2027. Six years may feel like a long time to wait to know if there are oceans of life in the L 98-59 solar system, but on cosmic scales, we'll know quicker than a blink of the eye.

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