A new method for finding planets: astronomers have discovered the “brother of Jupiter

An international team of astronomers has discovered one of the first planets using a new method of multi-year observations, images of which were obtained directly from a ground-based telescope. The newly discovered world scientists call “Jupiter’s brother. It is one of the first planets discovered using astrometry.

A new method of finding planets

Astronomers are always looking for new planets in outer space. But how do they find them? Previously, scientists used methods of observing stars, which can reflect the presence of planets around them. However, this method is not always effective, since not all planets leave a noticeable mark on the behavior of the stars.

In the new study, astronomers used the method of astrometry – measuring the subtle motions of a parent star over many years. By analyzing the data, scientists can determine whether the star is affected by any tidal forces. If such forces are present, it could very likely indicate the existence of a planet.

Discovery of “Jupiter’s brother”

The method of astrometry helped astronomers discover a new world, which they named AF Lep b. It is one of the first planets discovered using this method. The data allowed astronomers not only to measure its mass, but also to determine that its orbit is similar to that of the giant planets in our solar system.

Two direct images of the extrasolar planet were obtained in December 2021 and February 2023 using WM Keck, a 10-meter telescope located in Hawaii. When astronomers processed the Keck II telescope’s real-time observations to carefully remove the star’s glare, the planet immediately popped “out of the shadows,” and the longer they watched it, the more visible it became.

Direct images of the extrasolar world AF Lep b showed that its mass was about three times that of Jupiter. Moreover, scientists call this planet the “brother of Jupiter. It is also found to orbit the young sun-like star AF Leporis, located about 87.5 light-years from Earth.

New possibilities for finding exoplanets

“This method was first used to find a giant planet orbiting a young counterpart of our Sun,” says study co-author Brendan Bowler. – This opens up the possibility of using this approach as a new tool for finding exoplanets.”

The mass of the star AF Leporis turned out to be much greater than the mass of the planet AF Lep b. Despite this, the researchers found that the planet causes the stars to oscillate slightly around the center of mass of the planetary system as it orbits. Thanks to this, it was possible to discover a new world.

AF Lep b is about eight times farther from its star than Earth is from the Sun. This means that the planet is in a region where temperatures allow liquid water to exist on its surface. However, scientists cannot say for sure whether this planet has an atmosphere and life.


The discovery of the new planet AF Lep b using astrometry opens up new possibilities for finding exoplanets. Moreover, scientists have obtained data on the mass and orbit of this planet, which may help to better understand the processes of planetary system formation. But to answer questions about life on this planet, scientists need to do more research.

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