By Chris Skeldon 
The solar system is a highly organized place. Each planet stays in its orbit, at its own orbital distance from the sun, and mind its own business.
Most of the planetary systems we’ve discovered in the galaxy also seem to follow this trend. According to theory, two planets could share the same orbit — and now, for the first time, astronomers think we may have evidence of that in a small planetary system about 370 light-years from Earth.
These worlds that share orbits are known as Trojan planets or Trojan outer planets, after which they are named. asteroid population that share an orbit Jupiterit exits at gravitationally stable points along its orbit.
“Two decades ago, it was theoretically expected that pairs of planets of similar mass could share the same orbit around their star, the so-called Trojan planets or co-orbiting planets,” said astrophysicist Olga Balsalobre-Rosa of the Center for Astrobiology in Spain.
The system in which the discovery was made is already famous: PDS-70. Here we saw, for the first time, direct images Not just onebut who two outer planets In the process of formation, children Gas giants It is called PDS-70b and PDS-70c. Here, too, astronomers have found evidence of a Moon formation disk about one of the proto-exoplanets, PDS-70c.
Now, a closer look has revealed evidence of something – a point fainter than an exoplanet – sharing PDS-70b’s orbit. Calculations show that the mass of everything it contains is about twice that of Earth’s moon.
And although this point isn’t a planet – researchers are excited about its location.
Diagram showing the five Lagrange points of the Earth-sun system. (European Space Agency)
It is located in a place known as A Lagrangian point or Lagrangian point. Each two-body system has five such points: three along the line (L1, L2, and L3) connecting the two bodies, and two (L4 and L5) along the orbit of the smaller body. They are pockets of space where the gravitational interaction between the two bodies balances out gravitational force Necessary for a smaller body to move with them.
Jupiter Collect asteroids in L4 and L5, together known as Trojan asteroids. Earth has it too Some Trojan asteroids. These spots are also good parking spots for space observatories; JWST’s home One of the Lagrangian points of the Earth-Sun. So it makes sense that something a little bigger could park in one of these handy places, but we’ve found little evidence of that.
It seems fitting that we could find it in the PDS-70 system, lurking in the L5 Lagrange.
The ALMA image shows PDS-70b and its putative companion, indicated by a dashed circle. (ALMA (ESO / NAOJ / NRAO) / Balsalobre-Ruza et al.)
Who can imagine two worlds that share year length and housing conditions? Our work is the first evidence that this kind of world can exist.” Palsaloper Rosa says. “We can imagine that a planet could share an orbit with thousands of asteroids, as in the case of Jupiter, but it is very impressive to me that the planets can share the same orbit.”
Right now, the orbital partner is likely to be a thick cloud of dust, the building blocks of a new planet rather than an entire planet. This may help us not only understand the potential for Trojan exoplanets to form, but also the formation of planetary systems.
For example, Jupiter is believed to have collected Trojan horses over time and immigration from a point farthest from the sun. Studying Jupiter-like PDS-70b could shed light on this theory.
However, we will have to wait a bit for answers. The team will need to check the system again in 2026 to see if the bubble is moving along with PDS-70b as a common companion to the L5 Lagrangian.
“This will be a breakthrough in the field of exoplanets,” Palsaloper Rosa says.
Research published in Journal of Astronomy and Astrophysics.
Written by Michelle Starr
Posted in ScienceAlert