Coma Berenices is a traditional
asterismIn astronomy, an asterism is a pattern of stars seen in Earth's sky which is not an official constellation. Like constellations, they are composed of stars which, while they are in the same general direction, are not physically related, often being at significantly different distances from Earth....
that has since been defined as one of the 88 modern
constellationIn modern astronomy, a constellation is an area of the celestial sphere, defined by exact boundaries.The term "constellation" can also be used loosely to refer to just the more prominent visible stars that seem to form a pattern in that area.-Definitions:...
s. It is located near
LeoLeo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is , a corruption of the initial letter of Λεων . Leo lies between dim Cancer to the west and Virgo to the east.-Stars:...
, to which it formerly belonged and accommodates the North Galactic Pole. Its name means "Berenice's Hair", and refers to the legend of Queen Berenice II of Egypt, who sacrificed her long hair.
History and Mythology
Coma Berenices is one of the few constellations to owe its name to an historical figure, in this case Queen Berenice II of Egypt, wife of Ptolemy III Euergetes (
fl. 246 BC–221 BC), the king under whom
AlexandriaAlexandria , with a population of 4.1 million, is the second-largest city in Egypt, and is the country's largest seaport, serving about 80% of Egypt's imports and exports...
became an important cultural center.
In
243 BC-Egypt:* Ptolemy III returns from Syria by a revolt in Egypt. As a result, Seleucus II is able to regain control of his kingdom with the Egyptians being pushed out of Mesopotamia and part of Northern Syria....
, Ptolemy, in the Third Syrian War, undertook a dangerous expedition against the Seleucids who had murdered his sister. His newlywed bride, Berenice, swore to the goddess
AphroditeAphrodite is the Greek goddess of love, beauty and raw sexuality. According to Greek poet Hesiod, she was born when Cronus cut off Ouranos's genitals and threw them into the sea, and from the aphros arose Aphrodite.Because of her beauty other gods feared that jealousy would interrupt the peace...
to sacrifice her long, blonde hair, of which she was extremely proud, if her husband returned safely. He did, and she had her hair cut and placed it in the goddess' temple. By the next morning the hair had disappeared. To appease the furious king and queen (and save the lives of the temple priests), the court astronomer,
CononConon of Samos was a Greek astronomer and mathematician. He is primarily remembered for naming the constellation Coma Berenices.-Life and work:...
, announced that the offering had so pleased the goddess, that she had placed it in the sky. He indicated a cluster of stars that have since been called Berenice's Hair.
Coma Berenices consists of a number of stars close together, and has been recognized as a distinct
asterismIn astronomy, an asterism is a pattern of stars seen in Earth's sky which is not an official constellation. Like constellations, they are composed of stars which, while they are in the same general direction, are not physically related, often being at significantly different distances from Earth....
since the
Hellenistic periodThe Hellenistic period describes the era which followed the conquests of Alexander the Great. During this time, Greek cultural influence and power was at its zenith in Europe and Asia. It is often considered a period of transition, sometimes even of decline or decadence, between the brilliance of...
.
EratosthenesEratosthenes of Cyrene was a Greek mathematician, elegiac poet, athlete, geographer, and astronomer. He made several discoveries and inventions including a system of latitude and longitude...
referred to it as both "
AriadneAriadne , in Greek mythology , was daughter of King Minos of Crete and his queen, Pasiphaë, daughter of Helios, the Sun-titan...
's Hair" and "Berenice's Hair".
PtolemyClaudius Ptolemaeus , known in English as Ptolemy , was a Roman citizen of Greek ancestry. He was a mathematician, astronomer, geographer, astrologer and a poet of a single epigram in the Greek Anthology. He lived in Egypt under the Roman Empire, and is believed to have been born in the town of...
referred to it as "the lock" of hair, however, he did not list it as one of his 48 constellations, considering it as part of Leo, considering it to be the
tuftA tuft is a strip of yarn or string of varying length taped or glued to a surface as a technique for flow visualization. Tufts have been commonly used in aeronautics to study air flow direction, strength, and boundary layer properties....
at the end of the lion's tail.
Tycho BraheTycho Brahe, born Tyge Ottesen Brahe , was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
, who is usually given credit for Coma's promotion to constellation status, listed it in his star catalogue of 1602, but it originally occurred on a star globe by the cartographer Caspar Vopel from 1536, so Tycho Brahe obviously distinguished and measured up the constellation around a previous cartographers tradition, originating from
PtolemyClaudius Ptolemaeus , known in English as Ptolemy , was a Roman citizen of Greek ancestry. He was a mathematician, astronomer, geographer, astrologer and a poet of a single epigram in the Greek Anthology. He lived in Egypt under the Roman Empire, and is believed to have been born in the town of...
's explanatory texts in
AlmagestAlmagest is the Latin form of the Arabic name of a mathematical and astronomical treatise proposing the complex motions of the stars and planetary paths, originally written in Greek as by Ptolemy of Alexandria, Egypt, written in the 2nd century...
.
It appeared in
Johann BayerJohann Bayer was a German lawyer and uranographer . He was born in Rain, Bavaria in 1572. He began his study of philosophy in Ingolstadt in 1592, and moved later to Augsburg to begin work as a lawyer. He grew interested in astronomy during his time in Augsburg...
's
UranometriaUranometria is the short title of a star atlas produced by Johann Bayer.It was published in Augsburg, Germany, in 1603 by Christophorus Mangus under the full title Uranometria : omnium asterismorum continens schemata, nova methodo delineata, aereis laminis expressa. This translates to...
of 1603, and during the 16th century, a few other maps that were made of the sky followed suit.
Notable features
Although Coma Berenices is not a large constellation, it contains eight
Messier objectThe Messier objects are a set of astronomical objects first listed by French astronomer Charles Messier in his "Catalogue des Nébuleuses et des Amas d'Étoiles" included in the Connaissance des Temps for 1774...
s. The constellation is rich in
galaxiesA galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The name is from the Greek root galaxias [γαλαξίας], meaning "milky," a reference...
, containing the northern part of the
Virgo clusterThe Virgo Cluster is a cluster of galaxies at a distance of approximately 59 ± 4 Mly away in the constellation Virgo. Comprising approximately 1300 member galaxies, the cluster forms the heart of the larger Local Supercluster, of which the Local Group is an outlying member...
. There are also several
globular clusterA globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
s to be seen. These objects can be seen with minimal obscuration from dust because the constellation is not in the direction of the galactic plane. However, because of this fact, there are few
open clusterAn open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud, and are still loosely gravitationally bound to each other. In contrast, globular clusters are very tightly bound by gravity. Open clusters have been found only in spiral and irregular...
s (except for the Coma Berenices Cluster, which dominates the northern part of the constellation), diffuse
nebulaA nebula is an interstellar cloud of dust, hydrogen gas, helium gas and plasma...
e, or
planetary nebulaA planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas and plasma ejected during the asymptotic giant branch phase of certain types of stars late in their life...
e.
Stars
Coma Berenices is not particularly bright, having no stars brighter than fourth magnitude.
β Comae BerenicesBeta Coma Berenices is a main sequence dwarf star in the constellation of Coma Berenices. The Greek letter beta usually indicates that the star has the second highest visual magnitude in the constellation...
is the brightest
starA star is a massive, luminous ball of plasma that is held together by gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun...
in the constellation, at
magnitudeThe apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, normalized to the value it would have in the absence of the atmosphere...
4.26. It is intrinsically only slightly brighter than the
SunThe Sun is the star at the center of the Solar System. The Earth and other matter orbit the Sun, which by itself accounts for about 99.86% of the Solar System's mass....
, which gives us an idea of how faint the Sun would appear seen from 27 light years away.
The second brightest star in Coma Berenices is
α Comae BerenicesAlpha Comae Berenices is a star in the constellation Coma Berenices . Although it has the Bayer designation "alpha", at magnitude 4.32 it is actually fainter than Beta Comae Berenices. It has the traditional name Diadem...
(4.32
m), also called
DiademDiadem may refer to:*Diadem , a type of crownMilitary*HMS Diadem was a 64-gun third rate ship of the line in the Royal Navy launched in 1782 at Chatham and participated in the Battle of Cape St Vincent in 1787...
. The name represents the gem in Berenice's crown. It is a
binary starA 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 two components of almost equal magnitude. Because the
orbital planeThe orbital plane of an object orbiting another is the geometrical plane in which the orbit is embedded. Three non-colinear points in space suffice to define the orbital plane...
is so close to the Earth's line of sight, it was long suspected of being an eclipsing binary, but it now appears that the orbital tilt is 0.1° relative to the line of sight, so the stars do not eclipse each other as seen from Earth.
The only other fourth magnitude star in Coma Berenices is γ Comae Berenices (4.36
m).
Over 200 variable stars are known in Coma Berenices, although many of them are obscure.
FK Comae BerenicesFK Comae Berenices , yellow giant attracts attention by the enormous activity of its surface....
, which varies between 8.14
m and 8.33
m over a period of 2.4 days, is the prototype for the FK Com class of variable stars. It is believed that the variability of FK Com stars is caused by large, cool spots on the rotating surfaces of the stars. FS Comae Berenices is a semiregular variable that varies between 5.3
m and 6.1
m over a period of 58 days. R Comae Berenices is a
Mira variableMira variables, named after the star Mira , are a class of pulsating variable stars characterized by very red colors, pulsation periods longer than 100 days, and light amplitudes greater than one magnitude...
star that varies between 7.1
m and 14.6
m over a period of 363 days.
Richard Hinckley AllenRichard Hinckley Allen was a gifted polymath and amateur naturalist; his wide range of interests caused his friends to nickname him "the walking encyclopedia." His youthful ambition to pursue astronomy was thwarted by poor eyesight, and he became a moderately successful businessman instead...
lists among others the following star names for stars in Coma:
| Bayer Bayer AG is a German chemical and pharmaceutical company founded in Barmen, Germany in 1863. Today it is headquartered in Leverkusen, North Rhine-Westphalia, Germany. It is well-known for its original brand of aspirin...
|
Name |
Origin |
Meaning |
| α Com |
Diadem |
LatinLatin is an Italic language originally spoken in Latium and Ancient Rome. Through the Roman conquest, Latin spread throughout the Mediterranean and a large part of Europe...
|
diadem |
| β Com |
Al Ḍafīrah |
Arabic |
the curl |
| ρ Com |
Shang Tseang |
ChineseChinese or the Sinitic language is a language family consisting of languages mutually unintelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the two branches of Sino-Tibetan family of languages...
|
higher army general |
| 21 Com |
Kissīn |
Greek??? Greek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
|
species of ivyHedera is a genus of 15 species of climbing or ground-creeping evergreen woody plants in the family Araliaceae, native to the Atlantic Islands, western, central and southern Europe, northwestern Africa and across central-southern Asia east to Japan...
|
Coma Berenices Open Cluster
The Coma Berenices Cluster does not have a Messier or an NGC designation, but it is in the Melotte catalogue of open clusters, where it is designated Melotte 111. It is a large, diffuse open cluster of stars that range between 5th and 10th magnitudes, including several of the naked eye stars in the constellation. The cluster is spread over a huge region, more than 5 degrees across, near γ Coma Berenices. The cluster has such a large apparent size because it is relatively nearby, only around 270 light years away.
Globular clusters
M53Messier 53 is a globular cluster in the Coma Berenices constellation. It was discovered by Johann Elert Bode in 1775. M53 is one of the more outlying globular clusters, being about 60,000 light-years away from the Galactic Center, and almost the same distance from the Solar system.-External...
(NGC 5024) is a globular cluster that was discovered by
BodeJohann Elert Bode was a German astronomer known for his reformulation and popularization of the Titius-Bode law. Bode determined the orbit of Uranus and suggested the planet's name.-Biography:...
in 1775 and independently by
Charles MessierCharles Messier was a French astronomer most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 103 "Messier objects"...
in February 1777. Its brightness is 7.7
m, making it visible in binoculars. It is around 65,000 light years away and its total luminosity is around 200,000 times that of the Sun. Only 1° away is NGC 5053, a globular cluster that is sparser and has a less dense nucleus of stars. Its total luminosity is around 16,000 suns, which is one of the lowest luminosities of any globular cluster. It was discovered by Sir William Herschel in 1784. It is around magnitude 9.9 m. NGC 4147 is a somewhat dimmer (magnitude 10.2m) globular cluster with a much smaller apparent size.
Virgo cluster of galaxies
Coma Berenices contains the northern portion of the Virgo cluster (also known as the Coma-Virgo cluster), which is around 60 million light years away.
M100Messier 100 is a spiral galaxy about 52.5 million light-years away in the constellation Coma Berenices. It was discovered by Pierre Méchain in 1781. It is one of the brightest galaxies in the Virgo cluster. Five supernovae have been identified in M100: SN 1901B, SN 1914A, SN 1959E, SN 1979C and...
(NGC 4321) is a 9.4
m spiral galaxyA spiral galaxy is a galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the Nebulae” and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a...
seen face-on. At 7 arcminutes across, it has the largest apparent size of any galaxy in the Virgo cluster. It is located about 56 million light-years away. Its diameter is over 120,000 light years, making it among the largest spiral galaxies in the Virgo cluster. Photographs reveal a brilliant core, two prominent spiral arms and an array of secondary ones, as well as several dust lanes.
M85Messier 85 is a lenticular galaxy in the Coma Berenices constellation. It is 60 million light years away, making it the 94th most distant Messier object, and it estimated to be 125,000 light years across....
(NGC 4382) is a
lenticular galaxyA lenticular galaxy is a type of galaxy which is intermediate between an elliptical galaxy and a spiral galaxy in galaxy morphological classification schemes. Lenticular galaxies are disc galaxies which have used up or lost most of their interstellar matter and therefore have very little ongoing...
that is the northernmost outlier of the Virgo cluster. It is one of the brighter members of the cluster.
M98Messier 98 is an intermediate spiral galaxy about 60 million light-years away in the constellation Coma Berenices. It was discovered by Pierre Méchain on March 15, 1781 along with M99 and M100 and was cataloged as a Messier object on April 13, 1781...
(NGC 4192) is a bright, elongated spiral that is seen nearly edge-on. It has a small nucleus and faint but vast spiral arms.
M99Messier 99 is an unbarred spiral galaxy approximately 60 million light-years away in the constellation Coma Berenices....
(NGC 4254), about 1.5° southeast of M98, is a bright, round spiral seen face-on. R.H. Allen called it the "Pinwheel nebula", although this name is more often applied to the
Triangulum GalaxyThe Triangulum Galaxy is a spiral galaxy approximately 3 million light-years away in the constellation Triangulum...
.
M88Messier 88 is a spiral galaxy about 47 million light-years away in the constellation Coma Berenices. It was discovered by Charles Messier in 1781.-Properties:...
(NGC 4501) is a multi-arm spiral galaxy, seen about 30° from edge-on.
M91Messier 91 is a barred spiral galaxy about 63 million light-years away in the constellation Coma Berenices. It was most probably discovered by Charles Messier in 1781 and independently rediscovered by William Herschel on April 8, 1784. M91 is a member of the Virgo Cluster of galaxies....
(NGC 4548) is a
barred spiral galaxyA barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in approximately half of all spiral galaxies...
.
Coma cluster of galaxies
The Coma cluster of galaxies is to the north of the Virgo cluster. It lies much further off, however, around 230 to 300 million light years away. The cluster is quite large, containing 1,000 large galaxies and possibly up to 30,000 smaller ones. A survey by
Fritz ZwickyFritz Zwicky was born in Bulgaria, America-based Swiss astronomer. He was an original thinker, with many important contributions in theoretical and observational astronomy.-Biography:...
in 1957 identified 29,951 galaxies in the area that are brighter than 19.0
m. While some of these may be distant background objects, the total number of galaxies in the cluster is quite large.
Due to the great distance to the cluster, most of the galaxies are only visible in large telescopes. The brightest members are
NGC 4889NGC 4889, also Caldwell 35, is a supergiant class-4 elliptical galaxy, the brightest within the Coma cluster and a Caldwell object in the constellation Coma Berenices. It shines at magnitude +11.4. Its celestial coordinates are RA 13h00.1m, DEC +27°59'...
and NGC 4874, both of which are of thirteenth magnitude, with most of the other members being of fifteenth magnitude or dimmer. NGC 4889 is a giant elliptical galaxy. The Coma cluster contains comparatively few
spiral galaxiesA spiral galaxy is a galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the Nebulae” and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a...
.
NGC 4921NGC 4921 is a barred spiral galaxy in the Coma Cluster, located in the constellation Coma Berenices. It is about 320 million light-years from Earth. The galaxy has a nucleus with a bar structure that is surrounded by a distinct ring of dust that contains recently formed, hot blue stars...
is the brightest among them.
Other galaxies
M64 (NGC 4826) is known as the
Black Eye GalaxyThe Black Eye Galaxy was discovered by Edward Pigott in March 1779, and independently by Johann Elert Bode in April of the same year, as well as by Charles Messier in 1780...
because of its prominent dark dust lane in front of the galaxy's bright nucleus. It is relatively nearby, at around 17 million light years away from Earth. Recent studies have revealed that the interstellar gas in the outer regions of the galaxy rotates in the opposite direction from that in the inner regions, leading astronomers to believe that at least one satellite galaxy had collided with it less than a billion years ago.
NGC 4565NGC 4565 is an edge-on unbarred spiral galaxy about 20 million light-years away in the constellation Coma Berenices.The 10th magnitude galaxy sits perpendicular to our own Milky Way galaxy and is almost directly above the North Galactic Pole ....
is a spiral galaxy that is seen edge-on, and is called the "Needle Galaxy" for that reason. With an apparent length of 16 arcminutes, it has the largest apparent size of any galaxy seen edgewise from Earth. It appears quite thin and has a dark dust lane.
Quasars
QuasarA quasi-stellar radio source is a powerfully energetic and distant galaxy with an active galactic nucleus. Quasars were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended...
PG1247+26° is the brightest quasar visible in Coma Berenices. As well, W Com was originally identified as a variable star and so given a variable star designation, but later discovered to be a
BL LacertaeBL Lacertae or BL Lac is a highly variable, extragalactic AGN . It was first discovered by Cuno Hoffmeister in 1929, but was originally thought to be an irregular variable star in our own galaxy and so was given a variable star designation...
object. It is normally around magnitude 16.5 m, but has been known to reach 12th magnitude.
Other
Coma Berenices contains the North Galactic Pole, at
right ascensionRight ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
and
declinationIn astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Dec is comparable to latitude, projected onto the celestial sphere, and is measured in degrees north and south of the celestial equator...
(epoch J2000.0).
External links