Study: ‘Super Jupiter’ Planet Takes 100 Years to Orbit Star

Astronomers say they have observed a new exoplanet that orbits far away from its star although it is a large and massive planet.

An international group of researchers said they learned new things about the planet after examining data from the James Webb Space Telescope. The telescope is operated by the American space agency NASA.

The gas giant, which has been named Epsilon Indi A b, was first discovered in 2019. It is also known as a “super Jupiter,” meaning it is similar to Jupiter in our own solar system, but more massive.

Scientists estimate the exoplanet's diameter is about the same as Jupiter's, but it is about six times more massive. The team said the planet has an atmosphere rich in hydrogen like Jupiter's.

Epsilon Indi A b is estimated to be about 12 light-years away from Earth. A light year is the distance light travels in a year – about 9.5 trillion kilometers.

International researchers led by Germany's Max Planck Institute examined new telescope images of Epsilon Indi A b. They said they learned the massive exoplanet orbits the star Epsilon Indi A, which is part of a three-star system.

The scientists said one surprising discovery was that the exoplanet seems to take at least 100 years to orbit its star and possibly as many as 250 years. The research shows Epsilon Indi A b orbits its star at a distance equal to 15 times the distance from the Earth to our own sun.

The researchers said they were able to “directly” observe the gas giant by using a tool on the James Webb to block the light of the planet's main star. The team was then able to identify the exoplanet as a bright spot of infrared light.

The new findings recently appeared in a study in the publication Nature.

Scientists estimate the planet and star are about 3.5 billion years old. That is 1 billion years younger than our own solar system.

Elisabeth Matthews is an astrophysicist at the Max Planck Institute for Astronomy. Matthews led the research. She told The Associated Press in an email the exoplanet appears to be older and brighter than had been thought.

The team noted the planet's star is so bright that it can be seen with the unaided eye from the Southern Hemisphere.

But Matthews noted that nothing in the newly collected data suggests that Epsilon Indi A b has the right conditions to support life. “This is a gas giant with no hard surface or liquid water oceans," she said.

Matthews said studying worlds similar to Jupiter can help scientists understand “how these planets evolve” over many, many years.

The first exoplanets outside our solar system were confirmed in the early 1990s. NASA's total count today stands at about 5,690. The majority of these exoplanets were identified through the so-called “transit” method. This involves repeatedly observing drops in starlight that might happen when a planet partly blocks light from its star.

Land- and spaced-based telescopes also search for new data on exoplanets, especially ones that might be similar to Earth.

NASA launched the James Webb Space Telescope in 2021. It is currently the largest and most powerful astronomical observatory ever placed in space.

I'm Bryan Lynn.

The Associated Press reported this story. Bryan Lynn adapted the report for VOA Learning English.

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exoplanet - n. a planet of a star that sits outside the solar system

diameter – n. the length of a straight line through the center of an object or space

evolve – v. to develop gradually over time

transit – v. to pass through or across a place, area of country, on the way to someplace else