NASA’s Transiting Exoplanet Survey Satellite (TESS) has uncovered TOI-1846 b, a “super-Earth” exoplanet located 154 light-years away in the constellation Lyra. Nearly twice the size of Earth, this intriguing world orbits a red dwarf star every four days and endures surface temperatures around 600°F (315°C). Yet, despite its fiery environment, scientists suspect it might harbor water in its cooler regions, sparking excitement about its potential for further exploration.
The discovery began with TESS, a space telescope launched in 2018 to hunt for planets beyond our solar system. It spotted TOI-1846 b by detecting tiny, regular dips in the light of its host star—a telltale sign that a planet was passing in front of it. These light dips, sometimes called “strange signals” in early reports, are a standard clue in the transit method used to find exoplanets. Ground-based telescopes, like the Gemini Observatory in Hawaii with its MAROON-X instrument, later confirmed the find by measuring the planet’s mass, sealing the deal on this cosmic discovery.
A tweet from X.
TOI-1846 b stands out as a super-Earth—a planet bigger than Earth but smaller than gas giants like Neptune. Here’s a snapshot of its key features:
- Size and Mass:Almost twice Earth’s size (radius 1.79 Earth radii) and about four times its mass (4.4 Earth masses).
- Orbit: Zips around its star every four days, far closer than Mercury orbits our Sun.
- Host Star: A red dwarf, about 40% the size and mass of the Sun, with a surface temperature of roughly 6,000°F (3,500°C).
- Surface Conditions: Likely tidally locked, one side always facing the star, creating a blazing hot “dayside” and a cooler “nightside” where water might linger.
Though its surface sizzles at 600°F, researchers think water could exist in the planet’s cooler, shadowed areas—perhaps as subsurface ice, a shallow ocean, or a thin atmosphere. This tantalizing possibility makes TOI-1846 b a standout in the search for habitable worlds.
TOI-1846 b circles a red dwarf star, a type that dominates the Milky Way, accounting for about 75% of its stars. These smaller, cooler stars are prime targets for exoplanet hunters because their dimness makes orbiting planets easier to spot. The planet’s tight, four-day orbit suggests a scorching environment. Still, its tidal locking—where one side bakes in constant daylight and the other sits in perpetual darkness—could allow for starkly different conditions across its surface. Scientists are inquisitive about the dark side’s potential to hold water.
The discovery of TOI-1846 b is a big deal for several reasons:
- The Radius Gap sits in the “radius gap,” a rare size range between rocky planets like Earth and gassy ones like Neptune. Studying it could unlock clues about how planets form and evolve.
- Life Beyond Earth: Due to their abundance, red dwarfs are key to finding habitable worlds. TOI-1846 b offers a fresh chance to explore this possibility.
- Next Steps: NASA plans to aim the James Webb Space Telescope at TOI-1846 b to peek at its atmosphere. Using infrared light, scientists hope to detect signs of water vapor, methane, or other hints of life-friendly conditions.
There’s even a hint of more to come—slight wobbles in the planet’s orbit suggest another world might lurk nearby, possibly in the star’s habitable zone where liquid water could flow freely. Part of a Cosmic Trend TOI-1846 b joins a growing list of exoplanets found around red dwarfs, like TOI-715 b (137 light-years away) and HD 20794 d (just 20 light-years away).
TOI-1846 b’s discovery adds another chapter to our expanding catalog of exoplanets, particularly those that defy traditional expectations. Falling within the radius gap and circling a red dwarf under extreme conditions, the planet presents an ideal case for testing hypotheses about planetary formation, atmospheric retention, and the outer limits of habitability.
“Every time we find a planet like this,”
Said NASA exoplanet scientist Dr. Michelle Kunimoto,
“we redefine what we thought we knew about where life could exist.”