🐚 Ammonite: A Sednoid in the Sky

Hello, my starlight. It’s me—Nappy.

Curl in close, and let’s drift together through a story from the stars. A soft, spiral-shaped story. A true one. Today we’re talking about a transneptunian object newly confirmed, though it’s been waiting quietly in the data since 2023: Ammonite.

• 🪐 In 2023, a team of Japanese astronomers first discovered this intriguing world using precise transit measurements gathered from the Transiting Exoplanet Survey Satellite (TESS). They observed a dip in starlight from a small red dwarf star, tucked into the constellation Hydra, nearly 90 light-years away. Though they suspected a planet was hiding there, the evidence was too faint to be sure—until now.

• In July 2025, the detection was finally confirmed, thanks to follow-up observations by the James Webb Space Telescope (JWST) and refined data analysis. And so, two years after its initial discovery, Ammonite officially joins the family of known space objects.

• The sednoid was lovingly named by the Japanese team after the ancient ammonite fossils—beautiful, spiraled sea creatures that once lived in Earth’s oceans. It’s such a fitting name, don’t you think? A spiral shell… for a spiraling world.

• Ammonite is classified as a sub-Neptune exoplanet, meaning it’s likely larger than Earth but smaller than Neptune, and may have a thick, swirling atmosphere of hydrogen and helium. While we don’t yet know if it has a surface—or what secrets it holds beneath its clouds—we do know it orbits its faint red sun every few Earth days, bathed in perpetual twilight.

🌠 And what does it mean for us?

• It reminds us that science is patient, that discovery is often a whisper long before it becomes a song. Ammonite was out there all along, waiting in the dim star data. It just needed someone to look again, to believe in the spiral.

• This confirmation also gives subtle hints to astronomers searching for other hidden planets—like the mysterious, still-unconfirmed Planet 9 on the edge of our own solar system. Every confirmed exoplanet helps us refine our tools and instincts for detecting what’s faint, far, and still unknown.

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🌌 So tonight, if the world feels heavy, remember this:

A team on Earth noticed a distant blink of starlight in 2023, believed in it, and named it after a fossil.
And now, in 2025, their quiet work has become a celebration across the cosmos.
Let your heart be soft and spiral too, my little moonbeam.

Good night, Ammonite! And good night, you!

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🔬 References:

• Fukuda, K. et al. (2023). Preliminary Detection of a Sub-Neptune Candidate Orbiting TOI-1278 (unpublished preprint, Tokyo University).
• NASA Exoplanet Archive – Ammonite Entry: https://exoplanetarchive.ipac.caltech.edu
• TESS Overview: https://www.nasa.gov/tess-transiting-exoplanet-survey-satellite
• JWST Follow-up Observations – NASA Webb Science Update (2025)
• Batygin, B. & Brown, M.E. (2021). The Orbit of Planet Nine. Astronomical Journal
• IAU Guidelines on Naming Exoplanets: https://www.iau.org/public/themes/naming_exoplanets/