This past year saw the total number of exoplanets (worlds beyond our solar system) surpass 6,000 in number! Here's a look at some of the strangest new members to join the club:
- The Lemon-Shaped World — PSR J2322-2650 b
This curious planet (illustrated above) looks less like a globe and more like an oversized citrus fruit floating in space. Found orbiting a neutron star (remnants of an exploded supernova), PSR J2322-2650 b's extreme tidal forces stretch it into an ellipsoid shape unlike any other known planet. Its atmosphere is dominated by helium and molecular carbon, potentially creating soot clouds and even diamond rain!
- The Doom-Spiral Lava World – TOI-2431 b
Imagine an Earth-sized world trapped so close to its star that it completes a full orbit in just a hair over five hours? Discovered by the Transiting Exoplanet Survey Satellite (TESS), TOI-2431 b suffers relentless stellar heat (likely molten surface temperatures) and is gradually spiraling toward a violent demise as tidal forces pull it ever closer. It's one of the shortest-period exoplanets known and offers a blazing laboratory to study extreme planetary physics.
- The Twin-Tailed Hot Jupiter — WASP-121 b
Nicknamed "Tylos," WASP-121 b is a hot Jupiter-type planet with a flair for drama. Observations from the James Webb Space Telescope revealed it leaking two vast tails of escaping helium gas — one trailing behind and one mysteriously ahead — a phenomenon that doesn’t fit tidy models of atmospheric escape. Located about 858 light-years away, its odd atmosphere challenges our understanding of how close-in gas giants evolve under blistering stellar radiation.
- The Puffy Enigma — TOI-1453 c
Located at around 250 light-years from Earth in the Draco constellation, TOI-1453 c orbits its star alongside a rocky sibling. The planet defies easy categorization: it’s about 2.2 times the size of Earth but has a surprisingly tiny mass — only about 2.9 Earth masses—making it one of the least dense sub-Neptune-type planets ever found. That lightness suggests a thick, hydrogen-rich atmosphere or a water-rich interior, raising questions about how these "mini-Neptunes" form and evolve.
- The Eccentric Giant – GJ 2126 b
A Jupiter-like behemoth, GJ 2126 b has an extraordinary orbital eccentricity (about 0.85), meaning it swings from sizzling close to its star to much cooler afar over the course of a year-long journey. Such a stretched orbit isn’t just extreme, it offers a natural laboratory to study how giant planets interact with their birth disks and neighbors, and how systems can get stirred into oddball configurations.