One of the smallest constellations in the northern sky is Coma Berenices. Only three stars – α, β and γ Coma Berenices – make up its outline in the night sky. Despite its limited distribution in the sky, Coma Berenices contains a variety of fascinating objects for amateur astronomers; as many as eight of the 110 Messier objects are found here. During the spring, this constellation is well located in the middle of the south and a good piece over the horizon, more than halfway up towards zenith (see map below).
Picture 1. The sky to the south in mid-April at 11 pm.
Mythology
Coma Berenices means "Berenice's Hair" in Latin and is named after the Queen of the Egyptian province of Kyrene in the 21st century BC. At one point, Queen Berenice sacrificed a lock of hair to the Temple of Aphrodite for the prosperity in a war. The locks of hair disappeared and the mathematician and astronomer Konon from Samos explained that it had been taken to heaven and placed among the stars. In this way, the constellation got its name. With a little imagination, you can see figures and patterns among the stars and understand how the constellations have got their mythological names. However, seeing a lock of hair in the constellation Coma Berenices is not obvious; it was probably more eye-catching in a starry night sky in North Africa 2,200 years ago than it is from the Nordic countries today.
Stars
Diadem – α Comae Berenices – is the lower, left star of Coma Berenices (see star map) and is, oddly enough, the second brightest of the three main stars (the brightest star in a constellation is usually referred to α (alpha) and then the constellation's name in Latin). Its magnitude is 4.32, making it one of the more faint stars visible to the naked eye. From cities and other illuminated areas, it can be a challenge to see without a pair of binoculars. The distance from our own solar system is 63 light years.
Picture 2. Coma Berenices with deep sky objects (as a basis for observation with its own telescope, a larger star map is attached at the end of this Astroinfo).
β Comae Berenices is the center star and thus the brightest of the three stars and has a magnitude of 4.3. It is a dwarf star, and it is 29.8 light-years away from our own solar system.
γ Comae Berenices is a giant star 170 light-years away with a magnitude of 4.35.
In conclusion, we note that the three main stars are thus rather faint in light and that they are perceived to the naked eye to be about the same size in the sky. The distance between the respective pairs of stars (α and β Comae Berenices and β and γ Comae Berenices respectively) is approximately 10 degrees. A good way to measure 10 degrees in the sky is to tie your fist and stretch your arm up to the sky – 10 degrees is about a fist's apparent width in the sky.
Deep Space Objects
Thanks to all deep space objects, Berenice's hair is a popular constellation for amateur astronomers. So here are 8 of the objects in Messier's catalogue of 110 galaxies, nebulae and clusters of stars. In addition, Berenice's hair is next door to the constellation Virgo and the spectacular Virgo Cluster. In fact, several galaxies in Comae Berenices are included in the Virgo Cluster.
Virgo Cluster
Galaxies in the universe are generally bound together by gravity into clusters. Our own galaxy, the Milky Way, is part of the Local Group of some 50 galaxies (including the Andromeda Galaxy). The Virgo Cluster is a much larger galaxy cluster with somewhere between 1,300 and 2,000 galaxies. Both our own Local Group and the Virgo Cluster are also part of an even larger cluster of galaxy clusters, named the Virgo Supercluster. This supercluster consists of approximately 10,000 galaxies. The fact that it is called " Virgo Supercluster ", is because the Virgo cluster is such a large galaxy cluster and is in the center of the supercluster. The observable universe, in turn, contains millions of superclusters. The universe is big……
Fortunately, we are located well in our own galaxy to observe a handful of galaxies in the Virgo cluster, and several of them are in the hair of the constellation Coma Berenice. On the second star map, which is a "close-up" of Coma Berenice, you can see some of the galaxies in the Virgo Cluster at the bottom right. Only the galaxies in Messier's catalogue appear in the map, and some of them are counted among Coma Berenice and the others for the constellation Virgo. Below are a few of them, which are suitable to observe with a smaller telescope.
M85 - Elliptical Galaxy
The M85 is the galaxy farthest to the "northwest" of those in the Virgo cluster. As seen on the map, it is diagonally towards the β Comae Berenices. The magnitude is 10 and because it is an elliptical galaxy (without visible galaxy arms), it can easily be mistaken for a star in a smaller telescope. But the larger the telescope and higher the magnification, the easier it is to see its distribution. The researchers believe that it has been the victim of a collision with another galaxy a long time ago and that there may be a black hole at its center. The distance from Earth is about 60 million light-years.
M100
Just below the M85 is the large, beautiful, and typical M100 spiral galaxy. It is one of the brightest and largest galaxies in the Virgo Cluster and is about 55 million light-years away from Earth.
Picture 3. M100 - spiral galaxy. Photo: ESO
M53 - Globular Cluster
The M53 is a relatively bright so-called globular cluster that is easy to find with a pair of binoculars or a smaller telescope. As shown in the map, it is located about 1 degree "northwest" of α Coma Berenices. The magnitude is 8.33, which makes it appear as a blurry spot in a pair of ordinary binoculars or in a spotting scope. However, as with all deep space objects and especially the globular clusters, the larger the telescopes available, the greater the detail increases. In a telescope with at least 15 cm opening (e.g. Nexstar 6SE or Nexstar 8SE) and high magnification (2-300x), the 1,000s of stars glitter like jewels in a jewelry box.
Picture 4. M53 - globular star cluster. Photo: ESA / Hubble & NASA
M64 - Black Eye Galaxy
On a line between α and γ Coma Berenices are two larger galaxies: Messier 64 and NGC 4565. M64 is closer to α and NGC 4565 closer to β Coma Berenices.
M64 is a galaxy with a spectacular appearance; in a larger amateur telescope you see the large, dark space dust that hides the central parts of the galaxy, which makes the galaxy look like an eye. Another nickname for M64 is the Evil Eye Galaxy.
Thanks to the brightness of the galaxy (magnitude 9.36), it is visible with virtually all amateur instruments. The most important thing is that it is a clear and moonless night, as far away from light pollution as possible. And as usual: the larger the diameter of the telescope, the more details can be seen.
Picture 5. M64 - Black Eye Galaxy - spiral galaxy in Coma Berenices. Photo: NASA and The Hubble Heritage Team.
At first glance, M64 seems to be like any other rotating spiral galaxy, with galaxy arms spinning "slowly" in the galaxy's rotation. In the 1990s, however, scientists discovered that although the stars rotate with the galaxy, the outer interstellar gas rotates in the opposite direction. In the photo
from the Hubble Space Telescope are seen in the outer parts of the galaxy, masses of young blue stars that have recently formed from the rotating gas. The pink areas are nebulae which are illuminated by the ultraviolet light emitted by the newly formed stars. The amateur astronomers who live in the outer parts of the M64 certainly have a spectacular night sky to observe.
Text: Claes Tunälv