How Real Exoplanets Actually Get Named

Just 19 Planets Have a Real Name

Run a search for exoplanets and you'll land on nearly 6,000 confirmed worlds in NASA's archive. Almost none of them have a name you could say out loud without spelling it first. They're strings — HD 209458 b, Kepler-442c, TOI-700 d. Functional, but forgettable.

Only a small slice of that catalog carries anything close to a real name, the kind a poet might have chosen. The gap between "nearly 6,000 confirmed" and "a couple dozen renamed" is the whole story of how exoplanet naming actually works. It's stricter than most sci-fi fans assume.

How the Catalog System Actually Works

Every confirmed exoplanet gets a designation built from its host star. Take the star's catalog name — HD 209458, Kepler-442, TOI-700 — and append a lowercase letter starting at "b." The star itself is treated as "a," even though nobody writes it that way.

Order matters here, but not the order you'd expect. The letter reflects discovery order, not orbital position. A planet found second but sitting closer to its star than "b" still gets called "c." Astronomers are cataloging discoveries, not drawing a map.

Three catalogs do most of the work. The Henry Draper Catalogue (HD) covers stars mapped over a century ago. Kepler and TESS — NASA's two big planet-hunting missions — cover everything found by watching a patch of sky for the telltale dip in starlight.

The Numbers Behind the Naming Gap

Scale is the real obstacle. Nearly 6,000 confirmed worlds is too many for any single body to hand-name one at a time, so the International Astronomical Union — the organization with actual authority over celestial nomenclature since 1919 — mostly doesn't try.

That third stat trips people up every time. Kepler-186f is a famous planet — the first Earth-sized world found in another star's habitable zone. The "f" just means five planets in that system were confirmed before it. Nothing more poetic than bookkeeping.

2015: The Year the Public Got a Vote

December 2015. The IAU announces the results of its first public naming campaign, NameExoWorlds, and a pulsar system known for two decades only by a catalog number gets rechristened Draugr — Old Norse for the undead. Its confirmed planets become Poltergeist and Phobetor.

That system had earned the honor. PSR B1257+12 hosted the first exoplanets ever confirmed, back in 1992 — years before 51 Pegasi b became famous as the first planet found around a sun-like star. 51 Pegasi got new names in the same round: the star became Helvetios, the planet Dimidium.

Fomalhaut b, a planet astronomers spent years arguing whether it even existed, came out of the vote as Dagon. Nineteen planets total got names, under real rules: nothing commercial, nothing political, nothing honoring a living person, and every name pronounceable in more than one language.

Why the IAU Doesn't Name Everything

Here's the counterintuitive part: giving every exoplanet a real name would actually make the catalog worse. A name only helps if it's memorable and unique. Do that 6,000 times and you get noise, not clarity. Catalog codes scale. Poetry doesn't.

The IAU also treats naming rights as scarce on purpose. NameExoWorlds ran again in 2019 for the union's 100th anniversary, this time inviting individual countries to propose a name each. Beyond dedicated campaigns like these, there's no standing program quietly renaming planets in the background. A system left out of a vote just keeps its catalog code — indefinitely.

Catalog Code or Invented Word: Two Systems Compared

Lay the two approaches side by side and the philosophy gap is obvious. One system optimizes for precision across thousands of objects. The other optimizes for a handful of names people will actually remember.

Notice the two systems occasionally borrow from each other. Fomalhaut b's new name, Dagon, pulls from the same Semitic-mythology well that horror and fantasy writers have mined for a century — astronomers reaching for evocative language, not just precision. Fiction runs the trick in reverse.

What Science Fiction Keeps, and What It Skips

Watch how a franchise deploys a catalog-style name and it's rarely random. Alien's LV-426 sounds bureaucratic on purpose — a moon so unremarkable nobody bothered giving it a real name before the horror started. That's the opposite of what NameExoWorlds does: the IAU renames a world specifically because it's remarkable.

Most invented sci-fi names skip the catalog logic entirely and go straight for constructed phonology — Ursula K. Le Guin's Gethen, Frank Herbert's Arrakis, names built from invented linguistic roots rather than discovery order. If you're building a language-consistent alien name yourself, our alien name generator works the same way: unusual consonant clusters that still sound like one coherent tongue.

The utilitarian end of sci-fi naming sits closer to reality than people expect. Mining colonies, corporate outposts, and military designations in fiction mirror how real astronomers and real settlers actually label a place — functionally, without much affection. Our space colony name generator leans into that same unglamorous logic.

The Takeaway for Anyone Naming a World

Real astronomy suggests a rule most fiction ignores: a name everyone remembers should be rare, not default. Give every planet in your setting an equally lyrical name and none of them will land — the ear needs catalog numbers and utilitarian designations next to the Dagons and Dimidiums to make the mythological ones feel earned.

The most unrealistic thing about most fictional universes isn't the physics. It's that every single world got a beautiful name.

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