PDS 70, a young K7-type star some 370 light-years away from Earth in the constellation of Centaurus, is a unique target for planetary formation studies since it harbors two giant, Jupiter-like protoplanets: PDS 70b and PDS 70c. PDS 70 is surrounded by a highly structured protoplanetary disk with a wide inner cavity presumably carved by its planets. Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have detected a cloud of debris that might be sharing PDS 70b’s orbit and which, they believe, could be the building blocks of a new planet or the remnants of one already formed. If confirmed, this discovery would be the strongest evidence yet that two exoplanets can share one orbit.
Trojan asteroids are common inhabitants of the Solar System.
They are minor bodies populating the L4 and L5 Lagrange regions of a planet, leading and trailing it 60 degrees apart in the same orbital path.
The most famous example is the trojan asteroids of Jupiter — more than 12,000 rocky bodies that are in the same orbit around the Sun as the gas giant.
In 2022, astronomers theoretically demonstrated that trojans as massive as the main planet could be long-term stable, thus inspiring the concept of co-orbital planets.
The fact that the stability condition for co-orbitals is met for pairs of bodies with similar masses opens the possibility of searching for extrasolar trojans using the same methods and instruments as for the currently confirmed exoplanets.
“Two decades ago it was predicted in theory that pairs of planets of similar mass may share the same orbit around their star, the so-called trojan or co-orbital planets,” said Olga Balsalobre-Ruza, a student at the Centre for Astrobiology in Spain.
“For the first time, we have found evidence in favor of that idea.”
Also known as V* V1032 Cen and IRAS 14050-4109, PDS 70 is a located 370 light-years away in the constellation of Centaurus.
This 5.4-million-year-old star hosts two protoplanets and a…
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