How Did Stars Traditionally Get Their Names

Many stars have names that we recognize, including Polaris (also known as the north star). Others simply have designations that look like strings of numbers and letters. The brightest stars in the sky have names that date back thousands of years to a time when naked-eye observing was the state of the art in astronomy. So, for example, in the constellation Orion, the bright star Betelgeuse (in his shoulder) has a name that opens up a window into the very distant past, when Arabic names were assigned to the very brightest stars. The same with Altair and Aldebaran and many, many others. They reflect the cultures and sometimes even the legends of the Middle Eastern, Greek, and Roman people who named them. An HST image of the star Betelgeuse. Image Credit: NASA, ESA It has only been in recent times, as telescopes revealed more and more stars, that scientists began systematically assigning catalog names to stars. Betelgeuse is also known as alpha Orionis, and often shows up on maps as  ÃŽ ± Orionis, using the Latin genitive for Orion and the Greek  letter ÃŽ ±Ã‚  (for alpha) to indicate it is the brightest star in that constellation. It also has the catalog number HR 2061 (from the Yale Bright Star Catalog), SAO 113271 (from the Smithsonian Astrophysical Observatory survey), and is part of several other catalogs. More stars have these catalog numbers than actually have any other type of names, and the catalogs help astronomers bookkeep the many different stars in the sky.   It's All Greek to Me For most stars, their names come from a mix of Latin, Greek and Arabic terms. Many have more than one name or designation. Heres how it all came about.   About 1,900 years ago the Egyptian astronomer Claudius Ptolemy (who was born under, and lived during, the Roman rule of Egypt) wrote the Almagest. This work was a Greek text that recorded the names of stars as they had been named by various cultures (most were recorded in Greek, but others in Latin as per their origin). This text was translated into Arabic and used by its scientific community. At the time, the Arab world was known for keen astronomical charting and documentation, and in the centuries after the fall of the Roman Empire, became the central repository of astronomical and mathematical knowledge. So it was their translation that became popular among astronomers. The names for stars that we are familiar with today (sometimes known as traditional, popular or common names) are the phonetic translations of their Arabic names into English. For example, Betelgeuse, mentioned above, began as Yad al-JauzÄ , which translates roughly to the hand  [or shoulder] of Orion. However, some stars, like Sirius, are still known by their Latin, or in this case, Greek, names. Typically these familiar names are appended to the brightest stars in the sky. The constellation Orion and the Orion Nebula -- a starbirth region that can be spotted just below the Belt of Orion. Carolyn Collins Petersen Naming Stars Today The art of giving stars proper names has ceased, largely because all the bright stars have names, and there are millions of dimmer ones. It would be confusing and difficult to name every star. So today, stars are simply given a numerical descriptor to signify their position in the night sky, associated with particular star catalogs. The listings are based on surveys of the sky and tend to group stars together by some particular property, or by the instrument that made the initial discovery of  radiation, all the forms of light  from that star in a particular waveband. In fact, the study of starlight helps answer an often-asked astronomy question about what types of stars are out there, and how astronomers classify them. While not as pleasing to the ear, todays star-naming conventions are useful as researchers are studying a particular type of star in a specific region of the sky. All astronomers around the world agree to use the same numerical descriptions so as to avoid the kind of confusion that could arise if one group named a star a certain name and another group named it something else.   Additionally, such missions as the Hipparcos mission have imaged and studied millions of stars, and each of those bears a name that tells astronomers that they came from the Hipparcos dataset (for example). Polaris is a good example of another naming convention that is applied to a multiple star system. Polaris A is the primary star, Polaris Ab is a companion of the main star, and Polaris B is a separate star that orbits with the other two. This is an artists concept of how the system might look in an image. NASA/ESA/HST, G. Bacon (STScI) Star Naming Companies The International Astronomical Union (IAU) is charged with bookkeeping nomenclature for stars and other celestial objects. Official names are okayed by this group based on guidelines developed by the astronomical community. Any other names not approved by the IAU are not official names. When a star is designated a proper name by the IAU, its members will usually assign it the name used for that object by ancient cultures if one is known to exist. Failing that, significant historical figures in astronomy are usually chosen to be honored. However, this is rarely the case either  anymore, as catalog designations are a more scientific and easily used way to identify stars in research. There are a few companies that purport to name stars for a fee. Someone pays their money thinking they are going to name a star after themselves or a loved one. The problem is that these names are not actually recognized by any astronomical body. Theyre just a novelty, which is not always well explained by the people purporting to sell the right to name a star. So unfortunately if something interesting is ever discovered about the star someone paid a company to name, that unauthorized name isnt going to be used. The buyer gets a nice chart that may or may not show the star they named (some companies have actually just put a little dot on the chart), and little else. Maybe romantic, but certainly not legitimate. And, folks who are astronomers and/or work in planetariums have horror stories to tell about grieving family members getting a sympathy card with a star named for their husband or father or mother or sibling, showing up to see their late beloveds star, believing its a legitima tely named one. The astronomer or planetarian is then left to clean up the emotional mess made by the star-naming company. If people really want to name a star, they could go to their local planetarium and name a star on its dome in exchange for a nice donation. Some facilities do this or sell bricks in their walls or seats in their theaters. The funds go for a good educational cause and help the planetarium do its job of teaching astronomy. Its far more satisfying than simply paying a questionable company that claims official status for a name that wont ever be used by astronomers. Edited and updated by Carolyn Collins Petersen