Coma Berenices

Coma Berenices, or Berenice’s Hair, is a constellation in the northern sky. Coma Berenices is the 42nd constellation in size, occupying an area of 386 square degrees. It lies in the third quadrant of the northern hemisphere (NQ3) and can be seen at latitudes between +90° and -70°. The neighboring constellations are Boötes, Canes Venatici, Leo, Ursa Major, and Virgo.

[http://www.constellationsofwords.com/Constellations/ComaBerenices.html]

Coma Berenices, the flowing tresses of an Egyptian queen, from the Uranographia of Johann Bode (1801). The ‘nebulous mass’ described by Ptolemy that formed the basis of the constellation is in the upper right part of the illustration, on the crown of the hair.

[http://www.ianridpath.com/startales/comaberenices.htm]

Coma Berenices is one of the few constellations to owe its name to a historical figure, in this case Queen Berenice II of Egypt, wife of Ptolemy III Euergetes (fl. 246 BCE- 221 BCE), the king under whom Alexandria became an important cultural center. In 243 BCE, during the Third Syrian War, king Ptolemy undertook a dangerous expedition against the Seleucids, who had murdered his sister. His newlywed bride, Berenice, swore to the goddess Aphrodite to sacrifice her long, blonde hair, of which she was extremely proud, if her husband returned safely. He did, so she cut her hair and placed it in the goddess’s temple. By the next morning the hair had disappeared. To appease the furious king the court astronomer, Conon, 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.

Eratosthenes referred to Coma Berenices as both ‘Ariadne’s Hair and ‘Berenice’s Hair.’ Ptolemy referred to it as ‘the lock’ of hair; however, he did not list it as one of his 48 constellations, considering it to be a part of Leo, specifically, the tuft at the end of the lion’s tail. Tycho Brahe, 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 celestial globe by the cartographer Caspar Vopel from 1536. Gerardus Mercator has also been credited as its promoter in 1551. Coma Berenices and the now-defunct constellation Antinous are considered to be the first post-Ptolemaic constellations to be depicted on a celestial globe.

In Chinese astronomy, the stars of Coma Berenices are located in two areas: the Supreme Palace enclosure (Tài Wēi Yuán) and the Azure Dragon of the East (Dōng Fāng Qīng Lóng).

The asterism of Coma Berenices was recognized by several Polynesian peoples. The people of Pukapuka likely called it Te Yiku-o-te-kiole; the people of Tonga had three different names. These included Fatana-lua, Fata-olunga (also Fata-lalo), and Kapakau-o-Tafahi.

[http://blog.simulationcurriculum.com/articles/2015/6/2/constellation-in-focus-for-june-coma-berenices]

Though the formal constellation of Coma Berenices is focused on the Coma Berenices Cluster (seen just to the right of center), it covers much more territory, and includes. Diadem (Alpha Comae), and Beta (unnamed). Of the three indicated stars, only Gamma is part of the cluster. Coma Berenices is just south of Canes Venatici, the two constellations seen to the west of Bootes. Coma Berenices contains the North Galactic Pole (NGP), the northern perpendicular to the Milky Way, which is well marked by 31 Comae, ‘Polaris Galacticus Borealis.’ The South Galactic Pole is in Sculptor.

[http://stars.astro.illinois.edu/sow/com-t.html]

Constellation of Coma Berenices

[http://www.davidmalin.com/fujii/source/Com.html]

Coma Berenices is not particularly bright, having no stars brighter than fourth magnitude. Beta Comae Berenices is the brightest star in the constellation, at magnitude 4.2; it is 30 light-years from Earth. Like the Sun, it is a yellow-hued main-sequence star. It is intrinsically only slightly brighter than the Sun, which gives an idea of how faint the Sun would appear seen from Beta Comae’s distance.

The second brightest star in Coma Berenices is α Comae Berenices also called Diadem. The name represents the gem in Berenice’s crown. It is a binary star, with two components of almost equal magnitude. To the naked eye, it appears to be one star of magnitude 4.3. Because 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 two components are slightly yellow-tinged; both are of magnitude 5.1. This binary has a period of 26 years and is 47 light-years from Earth.

Gamma Comae Berenices, which is superimposed on the Coma Star Cluster, is an orange-hued giant star of magnitude 4.4, 170 light-years from Earth. Together with Alpha Comae Berenices and Beta Comae Berenices, it forms an imaginary inverted L-shaped support, from which the imaginary tresses of Berenice hang.

Coma Berenices contains three known exoplanets: HD 108874 b, HD 108874 c and HD 114762 b. HD 108874 b is a gas giant whose orbit lies in the star’s habitable zone. It is expected that any moons orbiting this planet are enriched in carbon, and are thus quite different from the silicate-rich bodies in the Solar System. HD 108874 b has a close Earth-like insolation. HD 108874 c is a gas giant which orbits beyond the star’s habitable zone, and receives insolation 15.9% that of Earth. It has minimum mass similar to Jupiter, although since the inclination of the orbit is not known the true mass of this planet could be much greater.

[https://en.wikipedia.org/wiki/HD_108874_b]

[https://en.wikipedia.org/wiki/HD_108874_c]

HD 114762 b is a massive gaseous extrasolar planet, approximately 132 light-years away. This optically undetected companion to the late F-type main-sequence star HD 114762 was discovered in 1989. The companion orbits its star every 83.9 days at an approximate distance of 0.35 AU, with an orbital eccentricity of 0.34; for comparison, this orbit is similar to that of Mercury but with twice the eccentricity. Depending on inclination angle, it has a mass between 11 and 63 MJ. HD 114762 b may be the first extrasolar planet ever detected, predating the 1992 pulsar planets found around PSR B1257+12 and main-sequence yellow dwarf 51 Pegasi. By 2012, its status as an exoplanet was confirmed.

[https://en.wikipedia.org/wiki/HD_114762_b]

In 2005, the brightest known supernova, SN 2005ap was detected in Coma Berenices. SN 2005ap was an extremely energetic type Ic supernova in the galaxy SDSS J130115.12+274327.5. It is reported to be the brightest supernova yet recorded, twice as bright as the previous record holder, SN 2006gy. As it occurred 4.7 billion light years from Earth it was not visible to the naked eye. It has been speculated that this supernova involved the formation of a quark star:

[https://en.wikipedia.org/wiki/SN_2005ap]

SN 2005ap: The Brightest Supernova Yet Found

What could cause a bang this big? This supernova explosion was so inherently bright that it could be seen nearly 5 billion light years away (a redshift of 0.28) even with a small telescope. Specific colors emitted during SN 2005ap indicate that it was a Type II supernova, a breed of stellar explosion that results when a high mass star begins fusing heavy elements in or near its core. Type II supernovas may be more powerful than their Type Ia cousins, but they are not currently more useful cosmologically because astronomers don’t understand how to accurately recover their intrinsic brightnesses. It is therefore dimmer Type Ia supernovas that are used by astronomers to calibrate the distance scale of the nearby universe. Were Type II supernova better understood, astronomers might be able to probe distances further into the universe, and so probe the stability of the strange dark energy that dominates the present universe. Pictured above in a digitally compressed image, the bright supernova SN 2005ap is visible on the right where no exploding star had been seen on the left less than three months before.
[http://apod.nasa.gov/apod/ap071016.html]

Coma Star Cluster: Image of the cluster taken by an astronaut on the International Space Station

Labeled image of the cluster

The Coma Star Cluster in Coma Berenices, designated Melotte 111 after its entry in the catalogue of star clusters by P. J. Melotte, is a small but nearby star cluster in our galaxy, containing about 40 brighter stars (magnitude 5 to 10) with a common proper motion. The Hipparcos satellite and infrared color-magnitude diagram fitting have been used to establish a distance to the cluster’s center of approximately 86 parsecs (280 ly). The distance established via the independent analyses agree, thereby making the cluster an important rung on the cosmic distance ladder. The open cluster is roughly twice as distant as the Hyades and covers an area of more than 7.5 degrees on the sky. The cluster is approximately 450 million years old. In the FOV of a good field glass most of its stars can be seen simultaneously. The brighter stars of the cluster make out a distinctive ‘V’ shape as seen when Coma Berenices is rising. 12 Comae Berenices, at magnitude 4.8, is the cluster’s brightest member. It used to represent Leo’s tail, but Ptolemy III, in around 240 BC, renamed it for the Egyptian queen Berenice’s sacrifice of her hair in a legend.

[https://en.wikipedia.org/wiki/Coma_Star_Cluster]

M53 (NGC 5024) is a globular cluster of magnitude 7.7 in Coma Berenices, and it is located 56,000 light-years from Earth. Only 1° away is NGC 5053, a globular cluster that is sparser and has a less dense nucleus of stars. Its luminosity is magnitude 9.9 or around 16,000 suns, which is one of the lowest luminosities of any globular cluster:

NGC 5053 and M53 in Coma Berenices

M53 and NGC5053 are shown in this field. M53 is the bright globular cluster in the upper right; NGC5053 is the dimmer globular cluster in the lower left. NGC5053 is about 53,500 light years distant from Earth which is close to the distance of M53. This puts both globular clusters relative close to each other in space. North is up in this image.

[http://jthommes.com/Astro/M53_NGC5053.htm]

The Coma Cluster (Abell 1656) is a large cluster of galaxies in the constellation Coma Berenices that contains over 1,000 identified galaxies. Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster. Its ten brightest spiral galaxies have apparent magnitudes of 12–14 that are observable with amateur telescopes larger than 20 cm. The central region is dominated by two supergiant elliptical galaxies: NGC 4874 and NGC 4889. The cluster’s mean distance from Earth is 99 Mpc (321 million light years) and it is within a few degrees of the north galactic pole on the sky. Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster:

[https://en.wikipedia.org/wiki/Coma_Cluster]

Hubble’s Sweeping View of the Coma Cluster of Galaxies

ASA’s Hubble Space Telescope captures the magnificent starry population of the Coma Cluster of Galaxies, one of the densest known galaxy collections in the universe.

The Hubble’s Advanced Camera for Surveys viewed a large portion of the cluster, spanning several million light-years across. The entire cluster contains thousands of galaxies in a spherical shape more than 20 million light-years in diameter.

Also known as ‘Abell 1656,’ the Coma Cluster is more than 300 million light-years away. The cluster, named after its parent constellation Coma Berenices, is near the Milky Way’s north pole. This places the Coma Cluster in an area unobscured by dust and gas from the plane of the Milky Way, and easily visible by Earth viewers.

Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. These featureless ‘fuzz-balls’ are pale goldish brown in color and contain populations of old stars. Both dwarf, as well as giant ellipticals, are found in abundance in the Coma Cluster.

Farther out from the center of the cluster are several spiral galaxies. These galaxies have clouds of cold gas that are giving birth to new stars. Spiral arms and dust lanes ‘accessorize’ these bright bluish-white galaxies that show a distinctive disk structure.

In between the ellipticals and spirals is a morphological class of objects known as S0 (S-zero) galaxies. They are made up of older stars and show little evidence of recent star formation, however, they do show some assemblage of structure- perhaps a bar or a ring, which may give rise to a more disk-like feature.

This Hubble image consists of a section of the cluster that is roughly one-third of the way out from the center of the cluster. One bright spiral galaxy is visible in the upper left of the image. It is distinctly brighter and bluer than galaxies surrounding it. A series of dusty spiral arms appears reddish brown against the whiter disk of the galaxy, and gives rise to the idea that this galaxy has been disturbed at some point in the past. The other galaxies in the image are either elliptical, S0 galaxies, or background galaxies far beyond the Coma Cluster sphere.

The data of the Coma Cluster were taken as part of a survey of a nearby rich galaxy cluster. Collectively they will provide a key database for studies of galaxy formation and evolution. This survey will also help to compare galaxies in different environments, both crowded and isolated, as well as to compare relatively nearby galaxies to more distant ones (at higher redshifts).

[http://www.nasa.gov/mission_pages/hubble/science/hst_img_20080610.html]

The sleeping giant: The placid appearance of NGC 4889 can fool the unsuspecting observer. But the elliptical galaxy, pictured in this new image from the NASA/ESA Hubble Space Telescope, harbors a dark secret. At its heart lurks one of the most massive black holes ever discovered.

Located about 300 million light-years away in the Coma Cluster, the giant elliptical galaxy NGC 4889, the brightest and largest galaxy in this image, is home to a record-breaking supermassive black hole. Twenty-one billion times the mass of the Sun, this black hole has an event horizon- the surface at which even light cannot escape its gravitational grasp- with a diameter of approximately 130 billion kilometers. This is about 15 times the diameter of Neptune’s orbit from the Sun. By comparison, the supermassive black hole at the center of our galaxy, the Milky Way, is believed to have a mass about four million times that of the Sun and an event horizon just one fifth the orbit of Mercury.

But the time when NGC 4889’s black hole was swallowing stars and devouring dust is past. Astronomers believe that the gigantic black hole has stopped feeding, and is currently resting after feasting on NGC 4889’s cosmic cuisine. The environment within the galaxy is now so peaceful that stars are forming from its remaining gas and orbiting undisturbed around the black hole.

When it was active, NGC 4889’s supermassive black hole was fueled by the process of hot accretion. When galactic material- such as gas, dust and other debris- slowly fell inwards towards the black hole, it accumulated and formed an accretion disc. Orbiting the black hole, this spinning disc of material was accelerated by the black hole’s immense gravitational pull and heated to millions of degrees. This heated material also expelled gigantic and very energetic jets. During its active period, astronomers would have classified NGC 4889 as a quasar and the disc around the supermassive black hole would have emitted up to a thousand times the energy output of the Milky Way.

The accretion disc sustained the supermassive black hole’s appetite until the nearby supply of galactic material was exhausted. Now, napping quietly as it waits for its next celestial snack, the supermassive black hole is dormant. However its existence allows astronomers to further their knowledge of how and where quasars, these still mysterious and elusive objects, formed in the early days of the Universe.

Although it is impossible to directly observe a black hole- as light cannot escape its gravitational pull- its mass can be indirectly determined. Using instruments on the Keck II Observatory and Gemini North Telescope, astronomers measured the velocity of the stars moving around NGC 4889’s center. These velocities- which depend on the mass of the object they orbit- revealed the immense mass of the supermassive black hole.

[https://www.spacetelescope.org/news/heic1602/]

The Black Eye Galaxy (M64, NGC 4826) is a galaxy which 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. It has a spectacular dark band of absorbing dust in front of the galaxy’s bright nucleus, giving rise to its nicknames of the ‘Black Eye’ or ‘Evil Eye’ galaxy. M64 is well known among amateur astronomers because of its appearance in small telescopes:

[https://en.wikipedia.org/wiki/Black_Eye_Galaxy]

Black Eye Galaxy (M64, NGC 4826)

The Black Eye Galaxy (M64, NGC 4826) is a relatively nearby spiral galaxy (distance 19 million light-years), in the constellation Coma Berenices, with a conspicuous dark feature to one side of the bright nucleus. Discovered by Johan Bode in 1779, it is also called the Sleeping Beauty Galaxy. Although M64 can be glimpsed with good binoculars, the oval eye only starts to show in telescopes of 10 to 15 cm aperture.

M64 has two counter-rotating systems of stars and gas in its disk: an inner zone, about 3,000 light-years in radius, that rubs along the inner edge of an outer disk, which rotates in the opposite direction at about 300 km/s and extends out to at least 40,000 light-years. This rubbing may explain the vigorous burst of star formation that is currently taking place in the galaxy and is visible as blue knots embedded in the huge dust lane.

The strange disk and dust lane, according to one theory, may be the result of material from a former companion galaxy that has been accreted but has yet to settle into the orbital plane of the disk. Another suggestion is that M64 may be the prototype for a class of galaxies called ESWAG, or evolved second wave activity galaxy. According to this idea, the main spiral pattern consists of an intermediate-aged stellar population. Star formation first evolved outside, following the density gradient, manufacturing stars as long as there was enough interstellar matter available, and then slowly died out. As matter was re-released into space from the evolved stars, by way of stellar winds, supernovae, and planetary nebulae, more and more interstellar matter accumulated again, until finally there was enough to enable a new wave of star formation to begin. This second wave, the theory maintains, has now reached the region where the dark dust lane appears.

[http://www.daviddarling.info/encyclopedia/B/Black_Eye_Galaxy.html]

NGC 4565 (also known as the Needle Galaxy or Caldwell 38) is an edge-on spiral galaxy about 30 to 50 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 (in the same way Polaris is located above the Earth’s North Pole). It is known as the Needle Galaxy for its narrow profile. First spotted in 1785 by William Herschel, it is one of the most famous examples of an edge-on spiral galaxy:

[https://en.wikipedia.org/wiki/NGC_4565]

NGC 4565: Galaxy on Edge

Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy’s bulging central core cut by obscuring dust lanes that lace NGC 4565’s thin galactic plane. An assortment of other background galaxies is included in the pretty field of view, with neighboring galaxy NGC 4562 at the upper left. NGC 4565 itself lies about 40 million light-years distant and spans some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.

[http://apod.nasa.gov/apod/ap120705.html]

NGC 4676, or the Mice Galaxies, are two spiral galaxies in the constellation Coma Berenices, about 290 million light-years away. They began the process of colliding and merging about 290 million years ago. Their name refers to the long tails produced by tidal action- the relative difference between gravitational pulls on the near and far parts of each galaxy- known here as a galactic tide. Members of the Coma cluster, it is a possibility that both galaxies have experienced collision, and will continue colliding until they coalesce:

[https://en.wikipedia.org/wiki/Mice_Galaxies]

NGC 4676: When Mice Collide

These two mighty galaxies are pulling each other apart. Known as the ‘Mice’ because they have such long tails, each spiral galaxy has likely already passed through the other. The long tails are created by the relative difference between gravitational pulls on the near and far parts of each galaxy. Because the distances are so large, the cosmic interaction takes place in slow motion- over hundreds of millions of years. NGC 4676 lies about 300 million light-years away toward the constellation of Bernice’s Hair (Coma Berenices) and are likely members of the Coma Cluster of Galaxies. The above picture was taken with the Hubble Space Telescope’s Advanced Camera for Surveys in 2002. These galactic mice will probably collide again and again over the next billion years until they coalesce to form a single galaxy.

[http://apod.nasa.gov/apod/ap150201.html]

The December Coma Berenicids are a meteor shower that lasts from December through January; it peaks between December 18 and 25. Despite slow intensity (one or two meteors per hour on average), its meteors are one of the fastest, with speeds of up to 65 km/s (40 mps):

Comae Berenicids meteor shower

Comae Berenicids meteor streams are groups of meteoroids originating from dust grains ejected from an unknown comet. These small dust grains (meteoroids) are distributed along the parent comet's orbit concentrated close to the comet nucleus with fewer grains farther away from the nucleus. Every time the Earth passes through this stream of dust particles (i.e. meteor stream), we experience what is known as a Comae Berenicids meteor shower. These brief streaks of light from meteors, sometimes called ‘shooting stars,’ peak on Sunday night the 25th December 2016 when earth moves through the center of the dust trail left behind by the comet.

To view the Comae Berenicids, go outside, find a dark spot and look north-east near the constellation of Coma Berenices for the Comae Berenicids radiant. Meteor showers are strictly for night owls or early risers. The best time to view the Comae Berenicids is from around 2h15 in the early morning to dawn. You should be able to see 5 streaks an hour or more during the peak. The Comae Berenicids meteor shower is active from the 12th Dec to 23rd Jan with fewer activity either side of the peak time.

[http://www.bashewa.com/wxmeteor-showers.php?shower=Comae+Berenicids]

[https://en.wikipedia.org/wiki/Coma_Berenices]

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