How are the stars named?

Astronomers have been studying them since ancient times. The stars, the most common stars in our galaxy, have received names throughout history. But how do you go about naming them?

These are the most common stars in our galaxy: the stars, these shiny balls of gas, dot the night sky. The study of their birth, evolution and death is crucial for the astronomers who observe them. Like comets, asteroids or exoplanets, the question of naming these celestial objects has obviously arisen. How did we decide to name them and classify them?

Named after their position in the constellation

Paris Observatory Explain that the way stars are named has changed throughout history. Thereby, ” during Antiquity, astronomers named stars after their position in the constellation to which they belonged », Says the observatory. Then, during the Middle Ages, this same principle was followed by Arab astronomers to assign names to the brighter stars in the sky. For example, the star Rigel which is found in the constellation Orion means “the foot” in Arabic. The names have entered into common usage.

Then, in the 17th century, the astronomer Johann Bayer played a role in the classification of stars, proposing his nomenclature which simplified their designation. His idea was to assign the letters of the Greek alphabet to the different stars of the same constellation: thus, alpha designates the brightest star, beta the second brightest, and so on (the Latin alphabet is then used , if the constellation has more stars than letters in the Greek alphabet). With this letter, he had the idea to associate the Latin name of the constellation.

Which gives for example for Arcturus, the brightest star of the Bouvier: α Bootis.

Stars have been named after their constellation. // Source: Nino Barbey for Numerama

A star can have several names

How does it work today, when the number of stars that we have identified is gigantic? Besides the brightest stars that already have a name, usually of Arabic origin, most are identified by an alphanumeric designation – an acronym followed by a number or celestial position.

« The stars are named after their number in specific catalogs », Summarizes the Paris Observatory. Which means that ” a star belonging to several catalogs therefore has several names “. As a result, a bright star like Vega, located in the constellation Lyra, has more than fifty different names, including: α Lyr; GJ 721; HIP 91262; HD 172167; CCDM J18369 + 3847A… Same thing for Betelgeuse, known under the names of: α Orionis; HR 2061; BD +7 1055; HD 39801; SAO 113271; or PPM 149643.

The International Astronomical Union (IAU) plays a role in the designation of celestial objects, including stars. A work group specializes in star names within the IAU, since 2016: it keeps a register of star names that have been approved. This list made it possible to clarify the situation, because problems could arise: stars which had several names, or identical names used for different stars… This list also excludes the possibility of naming, in the future, others celestial objects (asteroids, planetary satellites, exoplanets) such as already baptized stars.

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Source: Numerama by

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