Science & Technology

Scientists report a second supermoon beyond our solar system

Credits: Helena Valenzuela Widerström.

Astronomers have reported a second ultra-sized moon orbiting a Jupiter-sized planet beyond our solar system.

If confirmed, sightings could mean that exoplanets are as common in space as exoplanets, and that such large and small satellites are characteristic of the planetary system.

But that can be a long wait.

The first sightings of exoplanets four years ago are still awaiting confirmation, and the verification of this latest candidate is just as long and potentially controversial.

Discoveries published in Nature Astronomy, It was led by David Kipping of Columbia University and his Cool Worlds Lab, who reported the first exoplanet candidate in 2017.

“Astronomers have found more than 10,000 exoplanet candidates so far, but exoplanets are much more difficult,” said Kipping, who has been searching for exoplanets over the last decade.

“They are Terra Incognita.”

The team has discovered a giant exoplanet candidate orbiting the Kepler 1708b, a world 5,500 light-years away from Earth, in the direction of the Cigna and Lyra constellations.

This new candidate is about one-third smaller than the Neptune-sized moon, where Kipping and his colleagues previously discovered that they were orbiting a similar Jupiter-sized planet, Kepler 1625b.

According to Kipping, both Supermoon candidates could be made of gas deposited under the gravitational pull caused by their enormous size. If one astronomer’s hypothesis is correct, the Moon may have begun to live as a planet, but it will only be drawn into the orbits of larger planets such as Kepler 1625b and 1708b.

Both satellites are far away from the less gravitational host star that pulls the planet and strips it off. In fact, because there are more than 100 satellites between Jupiter and Saturn, which are analogs of exoplanets, researchers searched for a huge cold gas planet in wide orbit to search for exoplanets.

If other satellites were there, they would probably not be that huge, but would be difficult to find, Kipping said. “Eccentrics are generally the first to be detected in any survey,” he said. “A big thing that can be easily detected with limited sensitivity.”

For the same reasons as exoplanets, exomoon satellites fascinate astronomers. They have the potential to reveal where and how life emerged in the universe.

They are curious in their own right, and astronomers have wondered how these exoplanets can be formed and sustain life, and how they, if any, make the host planet habitable. I want to know if it plays a role.

In the current study, researchers examined a sample of the coldest gas giant captured by NASA’s planetary exploration spacecraft Kepler.

After a deep scan of 70 planets, they found one candidate, Kepler 1708b, with a moon-like signal. “It’s a stubborn signal,” Kipping said. “We threw a kitchen sink at this, but it doesn’t go away.”

Observations from other space telescopes such as Hubble will be needed to verify the findings. This is a process that can take years.

Four years later, the discovery of Kipping’s first exoplanet continues to be hotly debated. In a recent paper, he and his colleagues showed that one group of skeptics may have missed the Kepler 1625b moon in their calculations.

Meanwhile, Kipping and colleagues continue to investigate other evidence.

Eric Agol, a professor of astronomy at the University of Washington, said it was doubtful that this latest signal would be a reality. “It could be data fluctuations, either due to stars or equipment noise,” he said.

Others sounded more optimistic. “This is the best science,” said Michael Hipke, an independent German astronomer. “We find intriguing objects, make predictions, identify exoplanet candidates, or exclude them in future observations.”

“It’s a shame that only two passes have been observed, but I’m very excited to see the second exoplanet candidate,” he added. “More data is very cool.”

Finding moons and planets hundreds to thousands of light-years away from Earth is not easy. Satellites and planets can only be observed indirectly as they pass in front of the host star, and the star’s light becomes intermittently dark.

Since it is difficult to capture one of these fleeting passing signals with a telescope, it is also difficult to interpret the light curve data. It is even more difficult to detect because the satellites are small and block less light.

But remembering how the existence of exoplanets was greeted with the same skepticism as today’s exoplanets, Kipping said the search was worth it.

“These planets are aliens compared to our home system,” he said. “But they revolutionized our understanding of how planetary systems are formed.”

Scientists report a second supermoon beyond our solar system Scientists report a second supermoon beyond our solar system

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