Skip to main content

This tiny exoplanet 35 light-years away is half the mass of Venus

The L 98-59b planet.
This artist’s impression shows L 98-59b, one of the planets in the L 98-59 system that’s 35 light-years away. The system contains four confirmed rocky planets with a potential fifth, the farthest from the star, unconfirmed. ESO/M. Kornmesser

Of the roughly 4,200 planets outside our solar system discovered thus far, most are larger than Earth for the simple reason that it’s easier to spot a larger planet as it has a more noticeable impact on the environment around it. That’s why it’s notable when smaller exoplanets are discovered, like the recently identified planet L 98-59b, which is just half the mass of Venus.

The planet, orbiting the star L 98-59, which is just 35 light-years away, is part of a system of four or possibly five planets that are comparable to the rocky planets in the inner part of our solar system. The diminutive planet is the closest of the system to its star and is the smallest ever discovered using a method called radial velocity. This works by detecting a tiny wobble in the host star, which is caused by the gravity of the planet as it orbits, and this detection was made using the European Southern Observatory’s Very Large Telescope (VLT), which is located in the Atacama desert in Chile.

The other planets in this system are intriguing as well. One of them may even be habitable, as it is in the habitable zone (the distance from a star at which liquid water could exist on a planet’s surface), and it is a rocky planet like Earth or Venus.

“The planet in the habitable zone may have an atmosphere that could protect and support life,” said one of the authors, María Rosa Zapatero Osorio of the Centre for Astrobiology in Madrid, Spain, in a statement.

This makes the system a great target for further investigations with new and upcoming tools, like the James Webb Space Telescope, which will be able to detect whether exoplanets have atmospheres.

“This system announces what is to come,” said lead author Olivier Demangeon of the University of Porto. “We, as a society, have been chasing terrestrial planets since the birth of astronomy, and now we are finally getting closer and closer to the detection of a terrestrial planet in the habitable zone of its star, of which we could study the atmosphere.”

The findings are published in the journal Astronomy & Astrophysics.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
James Webb snapped a picture of an exoplanet for the first time
webb exoplanet direct detection exo image unlabeled 1

The James Webb Space Telescope has directly imaged an exoplanet for the first time. This is exciting because it is very rare for exoplanets to be directly imaged, as usually, their existence has to be inferred from other data. By taking an image of a planet outside our solar system, Webb demonstrates how we'll be able to gather more information than ever before about distant worlds.

There are over 5,000 known exoplanets, but the vast majority of these have been detected using techniques like the transit method, in which the light from a host star dips slightly when a planet passes in front of it, or radial velocity, in which a star is slightly tugged around by the gravity of a planet. In these methods, the existence of a planet is inferred because of the effect that can be observed on a star, so the planet itself isn't directly observed. In rare cases, however, an exoplanet can be observed directly, particularly if it is a large planet located relatively nearby.

Read more
Intriguing exoplanet could be entirely covered in ocean
Artistic rendition of the exoplanet TOI-1452 b, a small planet that may be entirely covered in a deep ocean.

Astronomers have discovered an intriguing exoplanet that could be entirely covered in water. The potential ocean world is called TOI-1452 b, located around 100 light-years away in the constellation of Draco.

The planet was discovered by an international team using data from NASA's Transiting Exoplanet Survey Satellite, or TESS, and is a type of planet called a super-Earth which is somewhat larger and heavier than Earth. It is in its host star's habitable zone, meaning it is the right distance from the star for liquid water to exist on its surface.

Read more
James Webb spots carbon dioxide in exoplanet atmosphere for first time
This is an illustration (artist’s impression) showing what the exoplanet WASP-39 b could look like, based on current understanding of the planet.

Researchers using the James Webb Space Telescope have detected carbon dioxide in an exoplanet atmosphere for the first time, demonstrating how using the new space telescope will help us to learn about far-off planets and even to find potentially habitable planets outside our solar system.

The planet in question, called WASP-39 b, is a gas giant orbiting a sun-like star and is located around 700 light-years away. Its mass if just a quarter of the mass of Jupiter, but its diameter is 1.3 times Jupiter's, so it is not dense and is very puffy. As it orbits very close to its star, with a year there lasting just over four Earth days, it has very high surface temperatures and is a type of planet called a hot Jupiter.

Read more