Minor planet names
Encyclopedia
Formal minor planet designations are number–name combinations overseen by the Minor Planet Center
, a branch of the IAU
. They are used for dwarf planet
s and small Solar System bodies
such as asteroid
s, but not comet
s. They are assigned to a body once its orbit is secured, and are unrelated to provisional designation
s, which are automatically assigned when an object is discovered.
The two parts of a formal designation are
The syntax is
or . The parentheses are now often dropped, as in 90377 Sedna
, according to the preference of the astronomer or journal. In practice, however, for any reasonably well-known object the number is mostly a catalogue entry, and the name or provisional designation is generally used in place of the formal designation: Sedna
, .
The convention for satellites of minor planets, such as the formal designation (87) Sylvia I Romulus for the asteroid moon Romulus
, is an extension of the Roman numeral convention that had been used, on and off, for the moons of the planets since Galileo's time.
Comets are also managed by the Minor Planet Center
, but use a different cataloguing system.
. The symbols grew increasingly complex as the number of objects grew, and, as they had to be drawn by hand, astronomers found some of them difficult. This difficulty was addressed by Benjamin Apthorp Gould
in 1851, who suggested numbering asteroids in their order of discovery, and placing this number in a circle as the symbol for the asteroid, such as ④ for the fourth asteroid, Vesta
. This practice was soon coupled with the name itself into an official number-name designation, "④ Vesta", as the number of minor planets increased. By ca 1858, the circle had been simplified to parentheses, "(4)" and "(4) Vesta", which was easier to typeset. Other punctuation such as "4) Vesta" and "4, Vesta" was also used, but had more or less completely died out by 1949.
The major exception to the convention that the number tracks the order of discovery or determination of orbit is the case of Pluto
. Since Pluto was initially classified as a planet, it was not given a number until a 2006 redefinition of "planet" that excluded it. At that point, Pluto was given the formal designation (134340) Pluto.
Minor Planet Center
The Minor Planet Center operates at the Smithsonian Astrophysical Observatory , which is part of the Center for Astrophysics along with the Harvard College Observatory ....
, a branch of the IAU
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
. They are used for dwarf planet
Dwarf planet
A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
s and small Solar System bodies
Small Solar System body
A small Solar System body is an object in the Solar System that is neither a planet nor a dwarf planet, nor a satellite of a planet or dwarf planet:...
such as asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s, but not comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s. They are assigned to a body once its orbit is secured, and are unrelated to provisional designation
Provisional designation in astronomy
Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calculated...
s, which are automatically assigned when an object is discovered.
The two parts of a formal designation are
- a number, historically assigned in approximate order of discovery, now assigned only after the orbit is secured, coupled with
- a name, either the name assigned by the discoverer, or, more commonly, the provisional designation.
The syntax is
(number) Name, for example (90377) Sedna90377 Sedna
90377 Sedna is a trans-Neptunian object discovered in 2003, which was about three times as far from the Sun as Neptune. For most of its orbit it is even further from the Sun, with its aphelion estimated at 960 astronomical units , making it one of the most distant known objects in the Solar System...
or . The parentheses are now often dropped, as in 90377 Sedna
90377 Sedna
90377 Sedna is a trans-Neptunian object discovered in 2003, which was about three times as far from the Sun as Neptune. For most of its orbit it is even further from the Sun, with its aphelion estimated at 960 astronomical units , making it one of the most distant known objects in the Solar System...
, according to the preference of the astronomer or journal. In practice, however, for any reasonably well-known object the number is mostly a catalogue entry, and the name or provisional designation is generally used in place of the formal designation: Sedna
90377 Sedna
90377 Sedna is a trans-Neptunian object discovered in 2003, which was about three times as far from the Sun as Neptune. For most of its orbit it is even further from the Sun, with its aphelion estimated at 960 astronomical units , making it one of the most distant known objects in the Solar System...
, .
The convention for satellites of minor planets, such as the formal designation (87) Sylvia I Romulus for the asteroid moon Romulus
Romulus (moon)
Romulus is the outer and larger moon of the main-belt asteroid 87 Sylvia, not to be confused with the directly Sun-orbiting asteroid 10386 Romulus. It follows an almost-circular close-to-equatorial orbit around the parent asteroid. In this respect it is similar to the other moon Remus.Romulus was...
, is an extension of the Roman numeral convention that had been used, on and off, for the moons of the planets since Galileo's time.
Comets are also managed by the Minor Planet Center
Minor Planet Center
The Minor Planet Center operates at the Smithsonian Astrophysical Observatory , which is part of the Center for Astrophysics along with the Harvard College Observatory ....
, but use a different cataloguing system.
History
By 1851 there were 15 known asteroids, all but one with their own symbolAstronomical symbols
Astronomical symbols are symbols used to represent various celestial objects, theoretical constructs and observational events in astronomy. The earliest forms of these symbols appear in Greek papyri of late antiquity. The Byzantine codices in which the Greek papyri were preserved continued and...
. The symbols grew increasingly complex as the number of objects grew, and, as they had to be drawn by hand, astronomers found some of them difficult. This difficulty was addressed by Benjamin Apthorp Gould
Benjamin Apthorp Gould
Benjamin Apthorp Gould was a pioneering American astronomer. He is notable for creating the Astronomical Journal, discovering the Gould Belt, and for founding of the Argentine National Observatory and the Argentine National Weather Service.-Biography:He was born in Boston, Massachusetts, son of...
in 1851, who suggested numbering asteroids in their order of discovery, and placing this number in a circle as the symbol for the asteroid, such as ④ for the fourth asteroid, Vesta
4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
. This practice was soon coupled with the name itself into an official number-name designation, "④ Vesta", as the number of minor planets increased. By ca 1858, the circle had been simplified to parentheses, "(4)" and "(4) Vesta", which was easier to typeset. Other punctuation such as "4) Vesta" and "4, Vesta" was also used, but had more or less completely died out by 1949.
The major exception to the convention that the number tracks the order of discovery or determination of orbit is the case of Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
. Since Pluto was initially classified as a planet, it was not given a number until a 2006 redefinition of "planet" that excluded it. At that point, Pluto was given the formal designation (134340) Pluto.
See also
- Astronomical naming conventionsAstronomical naming conventionsIn ancient times, only the Sun and Moon, a few hundred stars and the most easily visible planets had names. Over the last few hundred years, the number of identified astronomical objects has risen from hundreds to over a billion, and more are discovered every year...
- Meanings of asteroid namesMeanings of asteroid namesThis is a list of named minor planets , with links to the Wikipedia articles on the people, places, characters and concepts that they are named for.-See also:*List of minor planets*List of minor planets named after people...
- Name conflicts with minor planets
External links
- IAU FAQ on minor planets
- MPC explanation of provisional designations
- Dr. James HiltonJames L. HiltonJames Lindsay Hilton has been an astronomer at the United States Naval Observatory since 1986. In 1999 he published a new set of ephemerides for 15 of the largest asteroids for use in the Astronomical Almanac.-Education:...
, When Did the Asteroids Become Minor Planets?