Imagine a world where a year lasts almost a year and a half. Astronomers have discovered just such a place, a distant exoplanet nicknamed a "Cold Saturn" due to its similarities to our solar system's gas giant. Clocking in at a whopping 483 days for a single orbit around its star, this exoplanet holds the record for the longest year yet observed for a transiting exoplanet detected by NASA's TESS mission (Transiting Exoplanet Survey Satellite).
Discovered in September 2023, the exoplanet is part of a two-planet system orbiting a sun-like star roughly 700 light-years away. The team of international scientists used data from TESS to identify the planets, designated TOI-4600b and TOI-4600c. While TOI-4600b orbits its star in a relatively brisk 83 days, its companion, TOI-4600c, takes a record-breaking 483 days to complete its revolution.
While an Earth-year length might seem unusual for an exoplanet, it's important to remember that our solar system's gas giants have even longer orbits. Jupiter takes 12 Earth years to circle the Sun, and Saturn's year stretches over a staggering 29 Earth years. However, the significance of TOI-4600c lies in its detection method – the transit method. This technique relies on the dimming of a star's light as a planet passes in front of it, making long-period exoplanets more challenging to find.
The discovery of TOI-4600c opens exciting possibilities for studying the formation and evolution of exoplanetary systems. With its unique combination of a long orbit and cold temperatures (estimated to be around -117 degrees Fahrenheit), this "Cold Saturn" could provide valuable insights into the diversity of planetary systems in our galaxy.