A page from the star catalog in a 1515 printing of Ptolemy's Almagest.
From the time of its writing in the 2nd century CE, Claudius Ptolemy’s Almagest stood at the forefront of mathematical astronomy for nearly 1,500 years. This work included a catalog of 1,025 stars, listing their coordinates (in ecliptic longitude and latitude) and brightnesses. While astronomers within a few centuries realized that the models for the sun, moon, and planets all had issues (which we today recognize as being a result of them being incorrect, geocentric models relying on circles and epicycles instead of a heliocentric model with elliptical orbits), the catalog of stars was generally believed to be correct.
That was, until the end of the 16th century, when the renowned observational astronomer Tycho Brahe realized that there was a fundamental flaw with the catalog: the ecliptic longitudes were low by an average of 1 degree.
What’s more, Brahe proposed an explanation for why. He suggested that Ptolemy had stolen the data from the astronomer Hipparchus some 250 years earlier, and then incorrectly updated the coordinates.
The question of whether this was a cosmic coincidence or the oldest case of scientific plagiarism is a question that historians of astronomy have argued for over 400 years.
A folio from the Codex Climaci Rescriptus. Credit: Peter Malik
If you think writing paper is expensive these days, be glad you didn’t live in the middle ages. Back then, paper was as rare as hen’s teeth, so good luck finding some to write one. But if you happened to be a monk, chances are there were plenty of old books made of parchment. Many of them have useless stuff like old star catalogs, so why not just recycle the parchment for your new copy of religious literature?
The two brightest stars of the Centaurus constellation - (left) Alpha Centauri and (right) Beta Centauri. The faint red star in the center of the red circle is Proxima Centauri. Credit: Wikipedia Commons/Skatebiker
What springs to mind when we think of the most commonly-known stars in the night sky? Chances are, it would be stars like Sirius, Vega, Deneb, Rigel, Betelgeuse, Polaris, and Arcturus – all of which derive their names from Arabic, Greek or Latin origins. Much like the constellations, these names have been passed down from one astronomical tradition to another and were eventually adopted by the International Astronomical Union (IAU).
But what about the astronomical traditions of Earth’s many, many other cultures? Don’t the names they applied to heavens also deserve mention? According to the IAU, they do indeed! After a recent meeting by the Working Group on Star Names (WGSN), the IAU formally adopted 86 new names for stars drawn largely from the Australian Aboriginal, Chinese, Coptic, Hindu, Mayan, Polynesian, and South African peoples.
The WGSN is an international group of astronomers tasked with cataloging and standardizing the star names used by the international astronomical community. This job entails establishing IAU guidelines for the proposals and adoption of names, searching through international historical and literary sources for star names, adopting names of unique historical and cultural value, and maintaining and disseminating the official IAU star catalog.
Star map painting by Senior Wardaman Elder Bill Yidumduma Harney, featuring the Milky Way, the Moon, and ancestor spirits. Credit: IAU
Last year, the WGSN approved the names for 227 stars. With these latest additions, the catalog now contains the names of 313 stars. Unlike standard star catalogs containing millions or billions of stars designated using strings of letters and numbers, the IAU star catalog consists of bright stars with proper names derived from historical and cultural sources. As Eric Mamajek, chair and organizer of the WGSN, indicated in an IAU press release:
“The IAU Working Group on Star Names is researching traditional star names from cultures around the world and adopting unique names and spellings to avoid confusion in astronomical catalogues and star atlases. These names help ensure that intangible astronomical heritage from skywatchers around the world, and across the centuries, are preserved for use in an era of exoplanetary systems.”
A total of eleven Chinese star names were incorporated into the catalog, three of which are derived from the “lunar mansions” of traditional Chinese astronomy. This refers to vertical strips of the sky that act as markers for the progress of the Moon across the sky in the course of a year. In this sense, they provide a basis for the lunar calendar in the same way that the zodiac worked for Western calendars.
Two names were derived from the ancient Hindu lunar mansions as well. These stars are Revati and Bharani, which designate Zeta Piscium and 41 Arietis, respectively. In addition to being a lunar mansion, Revati was also the daughter of King Kakudmi in Hindu mythology and the consort of the God Balarama – the elder brother of Krishna. On the other hand, Bharani is the name for the second lunar mansion in Hindu astronomy and is ruled by Shurka (Venus).
Position of the Hindu Nakshatra Mandala, the “lunar mansions” in Hindu mythology. Credit: Wikipedia Commons/ Kishorekumar 62
Beyond the astronomical traditions of India and China, there are also two names adopted from the Khoikhoi people of South Africa and the people of Tahiti – Xamidimura and Pipirima. These names were approved for Mu¹ and Mu² Scorpii, the stars that make up a binary system located in the constellation of Scorpius. Xamidimura is derived from the Khoikhoi name for the star xami di mura – literally “eyes of the lion.”
Pipirima refers to the inseparable twins from Tahitian mythology, a boy and a girl who ran away from their parents and became stars in the night sky. Then you have the Yucatec Mayan name Chamukuy, a small bird that now designates the star Theta-2 Tauri, which is located in the Hyades star cluster in Taurus.
Four Aboriginal Australian star names were also added to the catalog, including the Wardaman names Larawag, Ginan, and Wurren and the Boorong name Unurgunite. These names now designate Epsilon Scorpii, Epsilon Crucis, Zeta Pheonicis, and Sigma Canis Majoris, respectively. Given that Aboriginal Australians have traditions that go back as far as 65,000 years, these names are some of the oldest in existence.
The brightest star to receive a new name was Alsephina, which was given to the star previously designated as Delta Velorum. The name stems from the Arabic name al-safinah (“the ship”), which refers to the ancient Greek constellation Argo Navis (the ship of the Argonauts). This name goes back to the 10th-century Arabic translation of the Almagest, which was compiled by Ptolemy in the 2nd century CE.
Artist’s concept of exoplanets orbiting a red dwarf star. Credit: NASA/JPL-Caltech
The new catalog also includes Barnard’s Star, a name that has been in common usage for about a century but was never an official designation. This red dwarf star, which is less than six light-years from Earth, is named after the astronomer who discovered it – Edward Emerson Barnard – in 1916. It now joins Alsafi (Sigma Draconis), Achird (Eta Cassiopeiae), and Tabit (Pi-3 Orionis) as being one of four nearby stars whose proper names were approved in 2017.
One of the hallmarks of modern astronomy is how naming conventions are moving away from traditional Western and Classical sources and broadening to become more worldly. In addition to being a more inclusive, multicultural approach, it reflects the spirit of modern astronomical research and space exploration, which is characterized by international cooperation.
Someday, assuming our progeny ever go forth and begin to colonize distant star systems, we can expect that the stars and planets they come to know will have names that reflect the diverse astronomical traditions of Earth’s many cultures.
The Sagittarius constellation, as imaged by the Hubble Space Telescope. Credit: IAU/NASA/ESA/HST
In May of 2016, the IAU Executive Committee approved of the creation of a special task force known as the Working Group on Star Names (WGSN). Composed of an international group of experts in astronomy, astronomical history, and cultural astronomy, the purpose of the WGSN is to formalize the names of stars that have been used colloquially for centuries.
This has involved sorting through the texts and traditions of many of the world’s cultures, seeking out unique names and standardizing their spelling. And after about six months, their labors have led to the creation of a new catalog of IAU star names, the first 227 of which were recently published on the IAU website.
This initiative grew out of the IAU’s Division C – Education, Outreach and Heritage group, which is responsible for engaging the public in all matters of astronomy. Their overall purpose is to establish IAU guidelines for the proposal and adoption of star names, to search historical and cultural literature for them, to adopt unique names that have scientific and historical value, and to publish and disseminate official IAU star name catalogs.
In this respect, the WGSN is breaking with standard astronomical practice. For many years, astronomers have named the stars they have been responsible for studying using an alphanumerical designation. These designations are seen as immensely practical, since star catalogs typically contain thousands, millions or even billions of objects. If there’s one thing the observable Universe has no shortage of, its stars!
However, many of these stars already have traditional names which may have fallen into disuse. The WGSN’s job, therefore, is to find commonly-used, traditional names of stars and determine which ones shall be officially used. In addition to preserving humanity’s astronomical heritage, this process is also intended to make sure that there is standardization in terms of naming and spelling, so as to prevent confusion.
What’s more, with the discovery of exoplanets becoming a regular thing nowadays, the IAU hopes to engage the international astronomical community in naming these planets according to their stars traditional name (if they have one). As Eric Mamajek, the chair and organiser of the WGSN, explained their purpose:
“Since the IAU is already adopting names for exoplanets and their host stars, it has been seen as necessary to catalogue the names for stars in common use from the past, and to clarify which ones will be official from now on.”
Artist’s impression of a system of exoplanets orbiting a low mass, red dwarf star. Credit: NASA/JPL
For instance, it can certainly be said that HD 40307 g – an exoplanet candidate that orbits within the habitable zone of its K-type star some 42 light years away – has a pretty clunky name. But what if, upon searching through various historical sources, the WGSN found that this star was traditionally known as “mikiya” (eagle) to the Hausa people of northern Nigeria? Then this super-Earth could be named Mikiya g (or Mikiya Prime). Doesn’t that sound cooler?
And this effort is hardly without precedent. As Mamajek explained, the IAU engaged in a very similar effort decades ago with respect to the constellations:
“A similar effort was conducted early in the history of the IAU, in the 1920s, when the 88 modern constellations were clarified from historical literature, and their boundaries, names, spellings, and abbreviations were delineated for common use in the international astronomical community. Many of these names are used today by astronomers for designations of variable stars, names for new dwarf galaxies and bright X-ray sources, and other astronomical objects.”
Much like the constellations, the new star names are largely rooted in astronomical and cultural traditions of the Ancient Near East and Greece. Their names are rendered in Greek, Latin or Aabic, and have likely undergone little change since the Renaissance, a time where the production of star catalogs, atlases and globes experienced an explosion in growth.
Others, however, are more recent in origin, having been discovered and named in the 19th or 20th centuries. The IAU is looking to locate as many ancient names as possible, then incorporate them into an official IAU-approved database with more modern stars. These databases will be made available for use by astronomers, navigators and the general public.
In accordance with WGSN guildines, shorter, one-word names are preferred, as are those that have their roots in astronomical, cultural or natural world heritage. The 227 names that have been released include 209 recently approved names by the WGSN, plus the 18 stars that the IAU Executive Committee Working Group for Public Naming of Planets and Planetary Satellites approved of in December 2015.
Among those names that were approved are Proxima Centauri (which is orbited by the closest exoplanet to Earth, Proxima b), as well as Rigil Kentaurus (the ancient name for Alpha Centauri), Algieba (Gamma-1 Leonis), Hamal (Alpha Arietis), and Muscida (Omicron Ursae Majoris).
This number is expected to grow, as the WGSN continues to revive ancient stellar names and add new ones that are suggested by the international astronomical community.
