Skip to main content
  1. Home
  2. Space
  3. News

How to locate a habitable exoplanet by looking for moons

By

When it comes to the search for habitable exoplanets, there are many factors to consider: A planet’s size and mass, its distance from its star, and its composition. But one factor that might be more important than you imagine is whether or not it has moons.

A new study in The Astronomical Journal suggests finding exomoons could be key to locating a potentially habitable Earth-like world in another solar system.

The PDS 70 system as seen with ALMA.
The PDS 70 system as seen with ALMA. ALMA (ESO/NAOJ/NRAO)/Benisty et al.

Although many astronomers agree that there likely are moons orbiting exoplanets beyond our solar system, there has not yet been a confirmed detection of an exomoon.

Recommended Videos

“In our solar system, we have an average of 20 moons orbiting around each planet. So, we suspected there are moons around planets in other systems, too. There is really no reason why there shouldn’t be any,” said study author Siegfried Eggl, a professor in the Department of Aerospace Engineering at the University of Illinois Urbana-Champaign.

However, there is evidence of moons forming in a system called PDS 70, which has been investigated used the Atacama Large Millimeter Array (ALMA). Previous research into this system found a moon-forming disk of dust and gas called a circumplanetary disk which could potentially form moons similar to those found around Jupiter in our solar system.

As moons are so tiny, it isn’t possible to spot them directly. Instead, astronomers must infer their presence from the effects they have on the system around them. For example, when a planet passes in front of a star and the star’s light dims for a short while, the amount of wobble in that planet can suggest the presence of a moon.

“This is an indirect proof of a moon because there’s nothing else that could tug on the planet in that kind of fashion,” Eggl said.

Finding an exoplanet with moons could even tell us more about whether it could support life. “If we can use this method to show there are other moons out there, then there are probably other systems similar to ours,” Eggl said. “The moon is also likely critical for the evolution of life on our planet, because without the moon the axis tilt of the Earth wouldn’t be as stable, the results of which would be detrimental to climate stability. Other peer-reviewed studies have shown the relationship between moons and the possibility of complex life.”

Editors' Recommendations

Topics
Georgina Torbet
Georgina Torbet
Space Writer
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
Stunning images of Jupiter’s moon Europa show it has a floating icy shell
Jupiter’s moon Europa was captured by the JunoCam instrument aboard NASA’s Juno spacecraft during the mission’s close flyby on Sept. 29, 2022. The images show the fractures, ridges, and bands that crisscross the moon’s surface.

This image of Jupiter’s moon Europa was captured by the JunoCam instrument aboard NASA’s Juno spacecraft during the mission’s close flyby on September 29, 2022. The image shows the fractures, ridges, and bands that crisscross the moon’s surface. Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing: Björn Jónsson (CC BY 3.0)

NASA's Juno mission is busy studying not only the planet of Jupiter, with its strange weather and strong magnetic field, but also several of its icy moons ,including the intriguing Europa. Often a top target of habitability research, Europa is exciting as a potential host for life because it is thought to have a liquid water ocean -- although this ocean is beneath an icy crust up to 15 miles thick. Juno has taken high-definition photos of Europa's surface, and scientists have recently analyzed this data to identify fractures and other features running across the icy shell.

Read more
How your aurora photographs are helping NASA study solar storms
A coronal aurora appeared over southwestern British Columbia on May 10, 2024.

A coronal aurora appears over southwestern British Columbia on May 10, 2024. NASA/Mara Johnson-Groh

This week has seen one of the most dramatic solar storms in decades, leading to views of auroras seen around the world as charged particles from the sun interacted with Earth's atmosphere. But the events weren't only notable for the gorgeous colors seen in the sky -- they are also a way for scientists to learn about the sun and how its activity varies over time.

Read more
James Webb telescope peers at the atmosphere of a rocky hell world
This artist’s concept shows what the exoplanet 55 Cancri e could look like. Also called Janssen, 55 Cancri e is a so-called super-Earth, a rocky planet significantly larger than Earth but smaller than Neptune, which orbits its star at a distance of only 2.25 million kilometres (0.015 astronomical units), completing one full orbit in less than 18 hours. In comparison, Mercury is 25 times farther from the Sun than 55 Cancri e is from its star. The system, which also includes four large gas-giant planets, is located about 41 light-years from Earth, in the constellation Cancer.

This artist’s concept shows what the exoplanet 55 Cancri e could look like. Also called Janssen, 55 Cancri e is a so-called super-Earth, a rocky planet significantly larger than Earth but smaller than Neptune, which orbits its star at a distance of only 2.25 million kilometers (0.015 astronomical units), completing one full orbit in less than 18 hours. NASA, ESA, CSA, R. Crawford (STScI)

When it comes to learning about exoplanets, or planets beyond our solar system, the James Webb Space Telescope is providing more information than ever before. Over the last decade or so, thousands of exoplanets have been discovered, with details available about these worlds, such as their orbits and their size or mass. But now we're starting to learn about what these planets are actually like, including details of their atmospheres. Webb recently investigated the atmosphere around exoplanet 55 Cancri e, finding what could be the first atmosphere of a rocky planet discovered outside the solar system.

Read more