The universe contains an immense number of objects, making a systematic method for identification necessary for scientific communication and tracking. Without a universally accepted system, astronomers worldwide would struggle to consistently reference the same celestial bodies. Assigning permanent names to planets, moons, asteroids, and stars is a highly structured function that adheres to internationally agreed-upon protocols. These protocols ensure every newly discovered object receives a unique and unambiguous designation, providing a consistent framework for all observations and theories.
Who Controls Celestial Naming?
The globally recognized body responsible for official astronomical nomenclature is an international organization of professional astronomers. This organization acts as the sole authority for assigning designations and proper names to celestial bodies and the features on their surfaces. Its mission is to promote and safeguard astronomy through worldwide cooperation by maintaining unambiguous naming systems.
This authority is structured with various working groups and committees that focus on specific classes of objects, such as planetary systems or small bodies like asteroids and comets. The formal definition of a “planet” was established in 2006, creating a classification framework for the objects these groups regulate. According to this definition, a celestial body must orbit the Sun, be massive enough for its gravity to pull it into a nearly round shape, and have cleared the neighborhood around its orbit of other significant objects.
Establishing Names for Solar System Planets and Minor Bodies
The major planets in our solar system already had names rooted in ancient Roman and Greek mythology long before formal naming bodies existed. These historical names, such as Mars and Jupiter, were grandfathered in and formally adopted to ensure continuity with astronomical tradition. The naming system for smaller solar system objects, however, follows a systematic, two-step process.
Upon discovery, a minor body like an asteroid or dwarf planet first receives a provisional designation assigned by the Minor Planet Center. This designation is a temporary technical label composed of the year of discovery and an alphanumeric code indicating the sequence of its finding (e.g., 1989 AC). Once the object’s orbit is precisely determined and confirmed, it is given a permanent sequential number, which can take several years.
After receiving its permanent number, the discoverer is invited to propose a proper name to the relevant working group. This proposal must adhere to strict thematic guidelines. For example, dwarf planets are typically named after creation myths, while asteroids are often named after figures from mythology, political figures from before the 19th century, or geographical locations. Proposed names must be short, non-offensive, and cannot closely resemble existing names to prevent confusion in astronomical catalogs.
How Exoplanets Receive Their Official Names
Planets orbiting stars outside our solar system, known as exoplanets, follow a naming convention that prioritizes scientific cataloging over mythological tradition. The most common identification is a technical designation derived from the host star’s name, followed by a lowercase letter. For example, in 51 Pegasi b, 51 Pegasi is the star, and ‘b’ signifies the first planet discovered orbiting it.
The host star’s name usually references the astronomical survey or catalog that first identified it (e.g., Kepler or WASP). The sequential letter designation starts with ‘b’ for the first planet (the star is considered ‘a’) and proceeds alphabetically, regardless of the planet’s distance from the star. This standardized system is necessary because thousands of exoplanets have been discovered, and a unique identifier is required for all research.
Despite the technical designations, a limited number of exoplanets and their host stars have been assigned proper names through public campaigns. Initiatives like NameExoWorlds allow the public to suggest memorable names that complement the scientific designation. These proper names must be pronounceable, culturally significant, and adhere to strict rules, including being between four and sixteen characters long and avoiding names of living people or commercial enterprises.