15760 Albion ( provisional designation ) was the first trans-Neptunian object to be discovered after

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...

and Charon. Measuring about 108–167 kilometres in diameter, it was discovered in 1992 by David C. Jewitt and Jane X. Luu at the Mauna Kea Observatory,

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

. After the discovery, they dubbed the object "Smiley" and it was shortly hailed as the tenth planet by the press. It is a "cold" classical Kuiper belt object and gave rise to the name ''cubewano'' for this kind of object, after the portion of its designation. Decoding its provisional designation, "QB₁" reveals that it was the 27th object found in the second half of August of that year. As of January 2018, around 2,400 further objects have been found beyond Neptune, a majority of which are classical Kuiper belt objects. It was named after

Albion Albion is an alternative name for Great Britain. The oldest attestation of the toponym comes from the Greek language. It is sometimes used poetically and generally to refer to the island, but is less common than "Britain" today. The name for Scot ...

from William Blake's mythology.

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named after

from the complex mythology of English poet and painter

William Blake William Blake (28 November 1757 – 12 August 1827) was an English poet, painter, and printmaker. Largely unrecognised during his life, Blake has become a seminal figure in the history of the Romantic poetry, poetry and visual art of the Roma ...

(1757–1827). Albion is the island-dwelling primeval man whose division resulted into '' The Four Zoas'': Urizen, Tharmas, Luvah/Orc and Urthona/Los. The name Albion itself derives from the ancient and mythological name of Britain. The official naming citation was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...

on 31 January 2018 (). The discoverers suggested the name "Smiley" for ,What Lurks in the Outer Solar System?
(Science@NASA, 13 September 2001) but the name was already used for an asteroid 1613 Smiley, named after the American astronomer Charles Hugh Smiley. It has received the number 15760 and remained unnamed until January 2018 (it was normally referred to simply as "QB1", even though this was technically ambiguous without the year of discovery).

Legacy

The next year in 1993, objects in similar orbits were found including (15788) 1993 SB, (15789) 1993 SC,

(181708) 1993 FW (181708) 1993 FW (Minor planet provisional designation, provisional designation ) is a cubewano and was the second trans-Neptunian object to be discovered after Pluto and Charon (moon), Charon, the first having been 15760 Albion, formerly known as ...

, and (385185) 1993 RO. Over one thousand bodies were found in the Kuiper belt orbiting between about 30 and 50 AU from the Sun in the twenty years after finding 15760 Albion. This revealed a vast belt of bodies, more than just Pluto and Albion themselves. By 2018, over 2000 Kuiper belt objects were discovered.

Physical characteristics

Based on a generic magnitude-to-diameter conversion, Albion measures approximately 167 kilometers (107 miles) in

diameter In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions a ...

, for an assumed

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

of 0.9 and an magnitude of 7.0. According to Mike Brown, who estimates a mean diameter of 108 km (66 mi), the object is too small for being considered a dwarf planet candidate ("probably not"). As of 2021, no rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

for this body has been obtained from photometric

observation Observation in the natural sciences is an act or instance of noticing or perceiving and the acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the percep ...

s. Its

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

and pole, as well as its composition and shape remain unknown.

Notes

Minor planet and asteroid provisional designations follow a format, in which the year it was discovered comes first, followed by the half-month it was discovered alphabetically (e.g. A=January 1–15, B=January 16–31 and so on, but skipping the letters I and Z) and then the order of its discovery alphabetically followed by a number (e.g. 1992 QA, 1992 QB, 1992 QC ... 1992 QY, 1992 QZ, 1992 QA1, 1992 QB1 and so on.) According to this, Q=August 16–31 and B1=25+2=27.

References

External links

Beyond Jupiter: 15760 Albion
Nikolai Wünsche, ''Journal for Occultation Astronomy'', October 2019

David Jewitt, ''Astronomy Beat'', 3 May 2010
New Planet Found in the Outer Solar System

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 m ...

, 2 October 1992
1992 QB1 - First Object Discovered in Kuiper Belt
David Jewitt, 14 September 1992 * * {{DEFAULTSORT:Albion 015760 Discoveries by David C. Jewitt Discoveries by Jane Luu Named minor planets 19920830