A second giant planet discovered orbiting the star HD 164604

Star system: HD 164604 | Distance from the Sun: 131 light years

Astronomers have discovered a new massive giant planet, HD 164604 c, which takes about 15 years to orbit its parent star. By combining data from ground-based telescopes and space missions like Gaia, researchers also refined our understanding of a previously known inner planet in the same system. 

The study reveals a fascinating orbital dance: the two planets might be moving in opposite directions (a retrograde orbit), suggesting a violent past involving gravitational scattering. While a same-direction alignment is possible, long-term simulations show that a retrograde setup is much more stable, and future data will soon confirm whether this planetary system truly defies the standard orbital alignment seen in our own solar system.

Scientific study

HD 164604 c: a second giant planet on a 15-yr orbit and the constraint of the planet-planet mutual inclination (external link)