How Are Stars Named? The Complete History of Star Names
Look up on a clear night and you might spot Sirius, Polaris, or Betelgeuse. But who decided those names? And what about the billions of stars too faint to see? Turns out, star naming has a wild history that spans thousands of years, multiple civilizations, and at least a dozen competing catalog systems. Here's how it all works.
Ancient Star Names: Where It All Started
The oldest star names come from ancient Babylon, roughly 3,000 years ago. Babylonian astronomers mapped the sky on clay tablets and gave names to the brightest stars they could track. The Greeks built on that work. Ptolemy's Almagest, written around 150 AD, cataloged 1,022 stars grouped into 48 constellations. Many of the star names we use today actually come from Arabic translations of Ptolemy's descriptions. When Arab scholars translated Greek astronomy texts during the Islamic Golden Age (8th to 14th century), they added their own names and observations. Aldebaran means "the follower" in Arabic because it follows the Pleiades across the sky. Betelgeuse comes from "yad al-jawza" meaning "hand of the central one." Rigel means "foot." Deneb means "tail." About 200 of the roughly 300 traditional star names have Arabic roots.
The Bayer System: Greek Letters Meet Constellations
In 1603, German astronomer Johann Bayer published the Uranometria, the first star atlas to cover the entire sky. His big innovation? A systematic naming system. He assigned Greek letters to stars within each constellation, roughly by brightness. The brightest star got Alpha, the next brightest Beta, and so on. Then he added the Latin genitive form of the constellation name. So the brightest star in Canis Major became Alpha Canis Majoris (also known as Sirius). The brightest star in Orion became Alpha Orionis (Betelgeuse). This system is still used today. But it has limits. The Greek alphabet only has 24 letters. Some constellations have way more visible stars than that. And Bayer didn't always follow the brightness rule strictly, so some Alpha stars aren't actually the brightest in their constellation.
Flamsteed Numbers: When Letters Weren't Enough
About a century after Bayer, English astronomer John Flamsteed took a different approach. Instead of ranking by brightness, he numbered stars within each constellation by their position, moving west to east across the sky. So you get names like 61 Cygni or 51 Pegasi. Flamsteed's system could handle many more stars than Bayer's 24 Greek letters. His catalog, published posthumously in 1725, included about 2,900 stars. That was a massive increase. The Flamsteed system is still widely used, especially for stars that don't have a Bayer designation. Fun fact: 51 Pegasi became famous in 1995 as the first Sun-like star confirmed to have an exoplanet orbiting it.
The Henry Draper Catalogue: Industrializing Star Names
By the late 1800s, astronomers needed to catalog far more stars than Greek letters or sequential numbers could handle. Enter the Henry Draper Catalogue (HD), compiled at Harvard Observatory between 1886 and 1949. It was funded by the estate of Henry Draper, a pioneer of astrophotography. The catalog was largely created by a team of women astronomers known as the "Harvard Computers," including Williamina Fleming, Annie Jump Cannon, and Cecilia Payne-Gaposchkin. They classified over 225,000 stars by their spectra. Stars got designations like HD 209458 (the first star where an exoplanet transit was observed). The HD catalog remains one of the most referenced in professional astronomy.
Modern Star Catalogs: Billions of Designations
Today's telescopes can see billions of stars, and each survey creates its own catalog. The Hipparcos satellite (1989-1993) precisely measured about 118,000 stars and gave them HIP numbers. Its successor, the Gaia mission, has cataloged nearly 2 billion objects. The Two Micron All Sky Survey (2MASS) added another naming layer for infrared observations. The Sloan Digital Sky Survey (SDSS) catalogs objects with long coordinate-based names like SDSS J153259.96-003944.1. A single star might have a dozen different designations across different catalogs. Sirius, for example, is also Alpha Canis Majoris, HR 2491, HD 48915, HIP 32349, and about 40 other names depending on which database you check.
The IAU: Who Officially Names Stars?
The International Astronomical Union (IAU) is the only organization recognized by the scientific community to name celestial objects. Founded in 1919, the IAU didn't formalize star proper names until 2016, when it created the Working Group on Star Names (WGSN). The WGSN has approved 451 official proper names as of 2024. These are mostly historical names that have been used for centuries, like Sirius, Vega, Polaris, and Arcturus. The IAU also runs public naming campaigns. In 2019, the NameExoWorlds project let people in 112 countries vote on names for exoplanets and their host stars. So regular people can participate in official naming. You just can't buy a name.
Variable Stars and Binary Stars Get Special Names
Not all stars behave the same way. Variable stars (stars that change brightness) have their own naming convention. The first variable discovered in a constellation gets the letter R, then S, T, and so on through Z. After Z, it goes RR, RS, up to ZZ, then AA through QZ. That gives 334 possible designations per constellation. After that, they just use V followed by a number, like V838 Monocerotis. Binary stars (two stars orbiting each other) add A and B suffixes. Alpha Centauri A is slightly brighter than Alpha Centauri B, and they orbit each other as a pair. Proxima Centauri (Alpha Centauri C) is the closest star to our Sun at 4.24 light-years away.
Constellation Names: The Framework Behind Star Names
Star names depend heavily on constellations, so understanding those matters too. The 88 official constellations were standardized by the IAU in 1922. They include Ptolemy's original 48 plus 40 more added by European explorers who mapped the southern sky. Each constellation has a Latin name and a three-letter abbreviation. Orion becomes Ori. Canis Major becomes CMa. When you see a star called Beta Orionis, the "Orionis" tells you it belongs to the Orion constellation. The constellation boundaries were precisely defined in 1930 by Belgian astronomer Eugène Delporte, so every point in the sky belongs to exactly one constellation.
Famous Star Names and Their Meanings
Some star names are surprisingly descriptive. Sirius (the brightest star in the night sky) comes from the Greek "seirios" meaning "scorching" or "glowing." Polaris just means "pole star" because it sits almost exactly at the north celestial pole. Antares means "rival of Mars" because its red color resembles the planet. Algol comes from Arabic "ra's al-ghul" meaning "head of the demon." It's a binary star that seems to "wink" every 2.87 days as one star eclipses the other. Ancient astronomers found that creepy enough to name it after a monster. Vega comes from Arabic for "swooping eagle." Capella means "little she-goat" in Latin. And Arcturus? "Bear guard" in Greek, because it follows Ursa Major (the Great Bear) across the sky.
Can You Name a Star After Someone?
Officially? No. The IAU doesn't sell star names and doesn't recognize names sold by commercial services. But star naming services have been popular gifts since the 1970s. Here's how they work: you pick a star, they record your chosen name in their registry along with the star's real astronomical coordinates, and you get a certificate. The coordinates are real. The star is real. The name just isn't recognized by the IAU. Think of it like naming a star the same way you might name a boat. The coast guard doesn't care what you call your boat, but it's still your boat and you still named it. For a lot of people, the gesture is what matters. Giving someone a star with their name on it, backed by real coordinates they can look up, is a genuinely thoughtful gift. Services like BuyMyPlanet use actual NASA data and real star coordinates. A certificate costs $24.99, or $29.99 for a premium version with a personalized web page and QR code.
How Many Stars Have Names?
Out of the estimated 200 billion trillion stars in the observable universe, only about 300 have traditional proper names. The IAU has officially approved 451 names. The Hipparcos catalog covers about 118,000 stars with precise measurements. The Gaia mission has cataloged nearly 2 billion objects. That still leaves the vast majority of stars completely unnamed and uncataloged. Even in our own Milky Way galaxy, which contains an estimated 100 to 400 billion stars, we've only scratched the surface. Most stars are red dwarfs too faint to see with the naked eye, and most will never receive individual attention from astronomers. That's part of what makes star naming special. When you pick a specific star and give it a name, you're doing something that astronomers will probably never get around to.
Famous stars to explore
Sirius
The brightest star in the night sky. Sirius is a dazzling blue-white star just 8.6 light-years away. Ancient Egyptians built their calendar around it.
Polaris
The North Star. For centuries, sailors and explorers used Polaris to find their way. It sits almost perfectly above Earth's north pole.
Vega
One of the brightest stars you can see from Earth. Vega was the first star ever photographed (back in 1850) and the first to have its spectrum recorded.
Betelgeuse
A red supergiant that could explode as a supernova any day now. Betelgeuse is so massive that if it replaced our Sun, it would swallow Mars.
Related articles & guides
Want to go deeper? Explore our guide to the brightest stars in the sky. Check out our planets page to explore our full catalog. You can also buy a star as a gift. And if you're curious whether you can actually buy a planet, we have a full article on that. Got questions? Visit our FAQ.
Frequently asked questions
Who has the authority to name stars?
The International Astronomical Union (IAU) is the only scientific body recognized to officially name stars. They formalized this in 2016 with the Working Group on Star Names, which has approved 451 proper names so far.
Are star names from commercial services official?
No, the IAU does not recognize names sold by commercial services. However, the star coordinates and data used are real. It's a symbolic gesture, not an official astronomical designation.
Why do so many star names come from Arabic?
During the Islamic Golden Age (8th-14th century), Arab scholars translated and expanded on Greek astronomical texts. They added their own observations and names, which stuck because their work was so influential in European astronomy.
How many stars are there in the universe?
Roughly 200 billion trillion (2 x 10^23) stars exist in the observable universe. Our Milky Way alone has between 100 and 400 billion. Only about 300 have traditional proper names.
Can I name a star as a gift?
Yes. While it won't be an IAU-recognized name, you can get a certificate with real astronomical coordinates. Services like BuyMyPlanet use real NASA data and star coordinates starting at $24.99.
Got Questions?
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