Monoceros
Encyclopedia
Monoceros is a faint constellation
on the celestial equator
. Its name is Greek for unicorn
. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius
. It is bordered by Orion
to the west, Gemini
to the north, Canis Major
to the south and Hydra
to the east. Other bordering constellations include Canis Minor
, Lepus
and Puppis
.
has a visual magnitude of 3.93, slightly brighter than Gamma Monocerotis
at 3.98.
However, Monoceros does have some interesting features to observe with the aid of a small telescope
. Beta Monocerotis
is an impressive triple star system, the three stars forming a triangle which seems to be fixed. The visual magnitudes of the stars are 4.7, 5.2 and 6.1. William Herschel
discovered it in 1781 and commented that it is "one of the most beautiful sights in the heavens".
Epsilon Monocerotis
is a fixed binary
, with visual magnitudes of 4.5 and 6.5.
S Monocerotis
, or 15 Monocerotis, is a bluish white variable star
and is located at the center of NGC 2264
. The variation in its magnitude is slight (4.2–4.6). It has a companion star of visual magnitude 8.
V838 Monocerotis
had an outburst starting on January 6, 2002.
Monoceros also contains Plaskett's Star
, which is a massive binary system whose combined mass is estimated to be that of almost 100 Suns put together.
: COROT-7b was detected by the COROT
satellite and COROT-7c
was detected by HARPS from ground-based telescopes. COROT-7b has the smallest known radius of any known exoplanet, 1.7 Earth radii. Both planets in this system were discovered in 2009.
in 1612 or 1613 and it was later charted by Jakob Bartsch
as Unicornus in his star chart of 1624.
Heinrich Wilhelm Olbers and Ludwig Ideler indicate (according to Richard Hinkley Allen
's allegations) that the constellation may be older, quoting an astrological work from 1564 that mentioned "the second horse between the Twins
and the Crab
has many stars, but not very bright"; these references may ultimately be due to Michael Scot
of the 13th century, but refer to a horse and not a unicorn, and its position does not quite match. Joseph Scaliger is reported to have found Monoceros on an ancient Persian sphere.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
on the celestial equator
Celestial equator
The celestial equator is a great circle on the imaginary celestial sphere, in the same plane as the Earth's equator. In other words, it is a projection of the terrestrial equator out into space...
. Its name is Greek for unicorn
Unicorn
The unicorn is a legendary animal from European folklore that resembles a white horse with a large, pointed, spiraling horn projecting from its forehead, and sometimes a goat's beard...
. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius
Petrus Plancius
Petrus Plancius was a Dutch astronomer, cartographer and clergyman. He was born as Pieter Platevoet in Dranouter, now in Heuvelland, West Flanders. He studied theology in Germany and England...
. It is bordered by Orion
Orion (constellation)
Orion, often referred to as The Hunter, is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous, and most recognizable constellations in the night sky...
to the west, Gemini
Gemini (constellation)
Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...
to the north, Canis Major
Canis Major
Canis Major is one of the 88 modern constellations, and was included in the 2nd-century astronomer Ptolemy's 48 constellations. Its name is Latin for 'greater dog', and is commonly represented as one of the dogs following Orion the hunter...
to the south and Hydra
Hydra (constellation)
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake...
to the east. Other bordering constellations include Canis Minor
Canis Minor
Canis Minor is a small constellation. It was included in the 2nd century astronomer Ptolemy's 48 constellations, and is still included among the 88 modern constellations...
, Lepus
Lepus (constellation)
Lepus is a constellation lying just south of the celestial equator, immediately south of Orion. Its name is Latin for hare. Although the hare does not represent any particular figure in Greek mythology, Lepus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it...
and Puppis
Puppis
Puppis is a constellation in the southern sky. Its name is the Latin word for the poop deck of a ship, and Puppis represents the deck of the ship and its deckhouses...
.
Stars
Monoceros is a constellation that is not very easily seen with the naked eye, with only a few fourth magnitude stars. Alpha MonocerotisAlpha Monocerotis
Alpha Monocerotis is a star in the constellation Monoceros.Alpha Monocerotis belongs to the spectral class G9 and is of apparent magnitude 3.93. It is approximately 144 light years from Earth.-References:#...
has a visual magnitude of 3.93, slightly brighter than Gamma Monocerotis
Gamma Monocerotis
Gamma Monocerotis is a star in the constellation of Monocerotis.----5 γ Monoceretos ----Named : Tempestris,Brightness : +3.9,distance from here : 645 light years ,Spectral Classification : Orange Giant ----Bayer classification : γ,...
at 3.98.
However, Monoceros does have some interesting features to observe with the aid of a small telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
. Beta Monocerotis
Beta Monocerotis
Beta Monocerotis is a triple star system in the constellation of Monoceros. To the naked eye, it appears as a single star with an apparent visual magnitude of approximately 3.74, making it the brightest visible star in the constellation...
is an impressive triple star system, the three stars forming a triangle which seems to be fixed. The visual magnitudes of the stars are 4.7, 5.2 and 6.1. William Herschel
William Herschel
Sir Frederick William Herschel, KH, FRS, German: Friedrich Wilhelm Herschel was a German-born British astronomer, technical expert, and composer. Born in Hanover, Wilhelm first followed his father into the Military Band of Hanover, but emigrated to Britain at age 19...
discovered it in 1781 and commented that it is "one of the most beautiful sights in the heavens".
Epsilon Monocerotis
Epsilon Monocerotis
epsilon Monocerotis is a star in the constellation of Monocerotis.EPS MON .location is guide for sky navigation toward Rosette nebula Right Ascension 6 hours 28 minutes 8 seconds, Declination 4 degrees 36 minutes, Magnitude 4.5, 6.5 Separation 13,4", Position Angle 27 degrees White giant ,...
is a fixed binary
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
, with visual magnitudes of 4.5 and 6.5.
S Monocerotis
S Monocerotis
S Monocerotis, also known as 15 Monocerotis, is a massive variable star system located in the constellation Monoceros. It is a spectroscopic binary system with an orbital...
, or 15 Monocerotis, is a bluish white variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
and is located at the center of NGC 2264
NGC 2264
NGC 2264 is the designation number of the New General Catalogue that identifies two astronomical objects as a single object:*the Cone Nebula,*the Christmas Tree Cluster,Two other objects are within this designation but not officially included:...
. The variation in its magnitude is slight (4.2–4.6). It has a companion star of visual magnitude 8.
V838 Monocerotis
V838 Monocerotis
V838 Monocerotis is a red variable star in the constellation Monoceros about 20,000 light years from the Sun, and possibly one of the largest known stars. The previously unknown star was observed in early 2002 experiencing a major outburst. Originally believed to be a typical nova eruption, it...
had an outburst starting on January 6, 2002.
Monoceros also contains Plaskett's Star
Plaskett's star
Plaskett's Star is a spectroscopic binary at a distance of around 6600 light-years...
, which is a massive binary system whose combined mass is estimated to be that of almost 100 Suns put together.
Planets
Monoceros contains two super-Earth exoplanets in one planetary systemPlanetary system
A planetary system consists of the various non-stellar objects orbiting a star such as planets, dwarf planets , asteroids, meteoroids, comets, and cosmic dust...
: COROT-7b was detected by the COROT
Corot
Corot may refer to:* Jean-Baptiste-Camille Corot, French landscape painter * COROT, a space mission with the dual aims of finding extrasolar planets and performing asteroseismology* COROT-7, a dwarf star in the Monoceros constellation...
satellite and COROT-7c
COROT-7c
COROT-7c is an extrasolar planet which orbits the G-type main sequence star COROT-7, located approximately 489 light years away in the constellation Monoceros...
was detected by HARPS from ground-based telescopes. COROT-7b has the smallest known radius of any known exoplanet, 1.7 Earth radii. Both planets in this system were discovered in 2009.
Deep sky objects
Monoceros contains many clusters and nebulae, most notable among them:- M50, an open clusterOpen clusterAn open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist...
- The Rosette NebulaRosette NebulaThe Rosette Nebula is a large, circular H II region located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy...
(NGC 2237-9,46), a diffuse nebula - The Christmas Tree Cluster and associated Cone NebulaCone NebulaThe Cone Nebula is an H II region in the constellation of Monoceros. It was discovered by William Herschel on December 26, 1785, at which time he designated it H V.27. The nebula is located about 800 parsecs or 2,600 light-years away from Earth. The Cone Nebula forms part of the nebulosity...
(NGC 2264)
History
Monoceros is a relatively modern constellation. Its first certain appearance was on a globe created by the Dutch cartographer Petrus PlanciusPetrus Plancius
Petrus Plancius was a Dutch astronomer, cartographer and clergyman. He was born as Pieter Platevoet in Dranouter, now in Heuvelland, West Flanders. He studied theology in Germany and England...
in 1612 or 1613 and it was later charted by Jakob Bartsch
Jakob Bartsch
Jakob Bartsch or Jacobus Bartschius was a German astronomer.-Biography:Bartsch was born in Lauban in Lusatia. He was taught how to use the astrolabe by Sarcephalus , a librarian in Breslau...
as Unicornus in his star chart of 1624.
Heinrich Wilhelm Olbers and Ludwig Ideler indicate (according to Richard Hinkley Allen
Star Names: Their Lore and Meaning
Star Names: Their Lore and Meaning is a book by Richard Hinckley Allen, published in 1899.It discusses the names of stars and constellations and their origin.-Author:...
's allegations) that the constellation may be older, quoting an astrological work from 1564 that mentioned "the second horse between the Twins
Gemini (constellation)
Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...
and the Crab
Cancer (constellation)
Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is . Cancer is small and its stars are faint...
has many stars, but not very bright"; these references may ultimately be due to Michael Scot
Michael Scot
Michael Scot was a medieval mathematician and scholar.- Early life and education :He was born in Scotland, and studied first at the cathedral school of Durham and then at Oxford and Paris, devoting himself to philosophy, mathematics, and astrology...
of the 13th century, but refer to a horse and not a unicorn, and its position does not quite match. Joseph Scaliger is reported to have found Monoceros on an ancient Persian sphere.
External links
- VISTA Reveals the Secret of the Unicorn — ESOESOESO, as a three-letter abbreviation, may stand for:* European Southern Observatory* Ensemble Studios Online* English Symphony Orchestra* Edmonton Symphony Orchestra* Executive Stock Options...
Photo Release - The Deep Photographic Guide to the Constellations: Monoceros
- The Constellations Web Page - Monoceros
- Star Tales – Monoceros