Meteor Magnets in Outer Space: Astronomers Find Elusive Giant Planets

UCR-led study finds elusive giant planets. (Image: University of California - Riverside)
UCR-led study finds elusive giant planets. (Image: University of California - Riverside)

Astronomers believe planets like Jupiter shield us from space objects that would otherwise slam into Earth. Now, they’re closer to learning whether giant planets act as guardians of solar systems elsewhere in the galaxy.

A UCR-led team has discovered two Jupiter-sized planets about 150 light years away from Earth that could reveal whether life is likely on the smaller planets in other solar systems. Stephen Kane, lead study author and UCR associate professor of planetary astrophysics, said:

Along with liquid water oceans, Kane said astronomers believe such planets have the ability to act as “slingshots,” pulling objects like meteors, comets, and asteroids out of their trajectories en route to impact with small, rocky planets.

Many larger planets have been found close to their stars. However, those aren’t as useful for learning about the architecture of our own solar system, where the giant planets — including Saturn, Uranus, and Neptune — are all farther from the Sun. Big planets far from their stars have, until now, been harder to find.

A study recently published in the Astronomical Journal details how Kane’s team found success in a novel approach combining traditional detection methods with the latest technologies.

One popular method of searching for exoplanets — planets in other solar systems — involves monitoring stars for “wobble,” in which a star moves toward and away from Earth. The wobble is likely caused by the gravitational pull a nearby planet is exerting on it. When a star wobbles, it’s a clue there may be an exoplanet nearby.

The “wobble” technique: blue wave shows movement toward Earth and the red occurs as the star heads away. (Image: NASA/JPL-Caltech)

The ‘wobble’ technique: blue wave shows movement toward Earth and the red occurs as the star heads away. (Image: NASA / JPL-Caltech)

When the planet is far from its star, the gravitational pull is weaker, making the wobble smaller and harder to detect. The other problem with using the wobble detection method, Kane said, is that it just takes a long time. Earth only takes a year to orbit the sun. Jupiter takes 12, Saturn takes 30, and Neptune takes an astonishing 164 years.

The larger exoplanets also take many years to circle their stars, which means observing a complete orbit could engulf an astronomer’s entire career. To accelerate the process, Kane and his team combined the wobble method with direct imaging. This way, if the team thought a planet might be causing wobble, they could confirm it by sight.

Obtaining a direct image of a planet quadrillions of miles away is no simple task. It requires the largest possible telescope, one that is at least 32 feet long and highly sensitive. Even from this distance, the light of the stars can overexpose the image, obscuring the target planets.

The team overcame this challenge by learning to recognize and eliminate the patterns in their images created by starlight. Removing the starlight allowed Kane’s team to see what remained. Kane said:

In this project, the team applied the combination of wobble and imaging method to 20 stars. In addition to the two being orbited by giant Jupiter-like planets that had not been previously discovered, the team also detected a third, previously observed star with a giant planet in its system.

Going forward, the team will continue to monitor 10 of the stars where planetary companions could not be ruled out. In addition, Kane is planning a new project to measure how long it takes these exoplanets to complete rotations toward and away from their stars, which cannot currently be measured. Kane concluded with:

Provided by: Jules Bernstein, University of California — Riverside [Note: Materials may be edited for content and length.]

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