Mu Columbae (μ Col, μ Columbae) is a

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Columba Columba () or Colmcille (7 December 521 – 9 June 597 AD) was an Irish abbot and missionary evangelist credited with spreading Christianity in what is today Scotland at the start of the Hiberno-Scottish mission. He founded the important abbey ...

. It is one of the few O-class stars that are visible to the unaided eye. The star is known to lie approximately 1,900

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s from the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

(with an error margin of a few hundred light years). This is a relatively fast rotating star that completes a full revolution approximately every 1.5 days. (Compare this to the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

, which at only 22 percent of this star's diameter rotates only once every 25.4 days.) This rate of rotation is fairly typical for stars of this class. Based on measurements of

proper motion Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...

and

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

, astronomers know that this star and

AE Aurigae AE Aurigae (abbreviated as AE Aur) is a runaway star in the constellation Auriga; it lights the Flaming Star Nebula. Description AE Aurigae is a blue O-type main sequence star with a mean apparent magnitude of +6.0, making it faint ...

are moving away from each other at a

relative velocity The relative velocity of an object ''B'' relative to an observer ''A'', denoted \mathbf v_ (also \mathbf v_ or \mathbf v_), is the velocity vector of ''B'' measured in the rest frame of ''A''. The relative speed v_ = \, \mathbf v_\, is the v ...

of over 200 km/s. Their common point of origin intersects with

Iota Orionis Iota Orionis (ι Orionis, abbreviated ι Ori) is a Star system, multiple star system in the celestial equator, equatorial constellation of Orion (constellation), Orion the hunter. It is the eighth-brightest member of Orion with an Appa ...

in the

Trapezium cluster The Trapezium or Orion Trapezium Cluster, also known by its Bayer designation of Theta1 Orionis (θ1 Orionis), is a tight open cluster of stars in the heart of the Orion Nebula, in the constellation of Orion. It was discovered by Galileo Galile ...

, some two and half million years in the past. The most likely scenario that could have created these

runaway star In astronomy, stellar kinematics is the observational study or measurement of the kinematics or motions of stars through space. Stellar kinematics encompasses the measurement of stellar velocities in the Milky Way and its satellites as well as ...

s is a collision between two

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

systems, with the stars being ejected along different trajectories radial to the point of intersection.

Etymology

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The Ancient China, ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categori ...

, Mu Columbae is called 屎,

Pinyin Hanyu Pinyin, or simply pinyin, officially the Chinese Phonetic Alphabet, is the most common romanization system for Standard Chinese. ''Hanyu'' () literally means 'Han Chinese, Han language'—that is, the Chinese language—while ''pinyin' ...

: Shǐ, meaning "Excrement" or "The Secretions", because this star is marking itself and stand alone in the asterism of the same name within the Three Stars mansion.

Etymology

References

Further reading