Astronomers may have found 2 planets that share the same orbit

Planets orbit same star

CAPE CANAVERAL, Fla. (AP) — Astronomers reported Wednesday the discovery of what could be two planets sharing the same orbit around their star.

They said it’s the strongest evidence yet of this bizarre cosmic pairing, long suspected but never proven.

Using a telescope in Chile, the Spanish-led team spotted a cloud of debris in the same orbit as an already confirmed planet circling this star, 370 light-years away in the constellation Centaurus. They suspect it’s either a planet in formation or remnants of a planet that once was.

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Asteroids are known to accompany planets around their star — for example, Jupiter and its so-called Trojan asteroids. But planets in the same orbit “have so far been like unicorns,” noted study co-author Jorge Lillo-Box of Madrid’s Center for Astrobiology.

“They are allowed to exist by theory, but no one has ever detected them,” he said in a statement.

The scientists said they will need to wait until 2026 in order to properly track the two objects around the star known as PDS 70.

Planets orbit same star
This image, taken with the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, shows the young planetary system PDS 70, located nearly 400 light-years away from Earth. The system features a star at its centre, around which the planet PDS 70b (highlighted with a solid yellow circle) is orbiting. On the same orbit as PDS 70b, indicated by a solid yellow ellipse, astronomers have detected a cloud of debris (circled by a yellow dotted line) that could be the building blocks of a new planet or the remnants of one already formed. The ring-like structure that dominates the image is a circumstellar disc of material, out of which planets are forming. There is in fact another planet in this system: PDS 70c, seen at 3 o’clock right next to the inner rim of the disc.
ALMA (ESO/NAOJ/NRAO) /Balsalobre-Ruza et al.


The confirmed planet with the suspected tagalong takes 119 years to complete a lap. A gas giant, it’s three times the size of Jupiter. Another gas giant is known to circle this star, albeit from a much greater distance.

Lead author Olga Balsalobre-Ruza of the Center for Astrobiology in Madrid, said the findings, published in the journal Astronomy and Astrophysics, are “the first evidence” that such double worlds might exist.

“We can imagine that a planet can share its orbit with thousands of asteroids as in the case of Jupiter, but it is mind-blowing to me that planets could share the same orbit,” she said in a statement.


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