Kinds of Galaxies and Constellations

The galaxy is a very large system, consisting of stars and interstellar matter. Typically contain several billion stars, with masses between a few million to a few billion times that of our sun. With an area of ​​several thousand to 100,000 light years. Besides simple stars, they typically contain different types of star clusters and nebulae. The galaxy is a system bound by gravity which consists of the stars (with all its manifestations, such as neutron stars and black holes), cosmic dust + gas interstellar medium, and the possibility of hypothetical substance known as dark matter. The origin of the word galaxy is derived from the Greek language meaning Galaxias milk. Galaxias word when it tends to refer to our galaxy: galaxy galaxy. The galaxy consists of hundreds of stars (both binary stars and single stars), cluster, nebulae, planets and interstellar medium. Sun, which is one of the stars surrounding the galaxy by an orbit of its own. Galaxy based on its shape divided into three main types, namely elliptikal Galaxies, Galaxies spiral and irregular galaxies.

Type of elliptical galaxy is a type of galaxy that is estimated to have ellipsoidal shape and look soft because its bright light between the stars, almost his entire physical form and bright flat. The morphology of elliptical galaxies amazingly diverse ranging from nearly spherical shaped like eplisoidal nearly flat. With its wide range of existing forms, it turned out to greatly affect the number of its many stars are there in the galaxy. Ranging from hundreds of millions of stars up to more than a trillion stars. Classification elliptical morphology has been classified by Edwin Hubble in the Hubble classification scheme. Examples of this type of elliptical galaxies is M32, M49 and M59.

Hubble classification scheme in elliptical galaxies

Spiral galaxy type is the type of whirlpool galaxy consisting of stars and interstellar medium, which at its center line or center of the galaxy consists of stars stars are very old age. Judging from its shape, type spiral galaxies have bright arms at his side. In the Hubble classification scheme type spiral galaxy was given a list with the code S (Spiral) and SB (Barred Spiral) depending on the shape of his arm, followed the alphabet to indicate the level of density between the spiral arms and the central bulge of the galaxy. As his case of a star with its planets, galaxies spiral arms are always around the center of the galaxy at speeds relatively constant despite the time it takes to surround her very long. Spiral arms are regions in the galaxy's most solid material is often called "Densiy Waves". This section interstellar gravity began docking so the visible spiral arms of a galaxy the more the number of stars and this is the section where birth to young stars. Examples of the types of spiral galaxies is M31 (andromeda), M33 (Triangulum) and M51 (Whirlpool)

Hubble Classification of Spiral Galaxies and Barred Spiral

Irregular galaxy types. Type of irregular galaxy in question is a type of galaxy that its shape is not elliptical or spiral. In this type of galaxy shapes of galaxies variety are called "dwarf" galaxies or dwarf galaxies because the galaxies are smaller than galaxies in general, Ring galaxies are galaxies that his form like a ring in the middle where there is a center of the galaxy and Lentikular galaxy where the shape of the galaxy is a mix between elliptical and spiral types. Examples of this type of dwarf galaxy is M110, Ring Galaxies are attractions Hoag and Lentikular galaxy is NGC 5866.HG
(Reference: en.wikipedia.org)

Examples of elliptical galaxy type

Sample Type Spiral and Barred Spiral Galaxies

Sample Type Galaxies Not Regular

Various kinds of galaxies are Amazing

1. Sombrero galaxy

The Sombrero Galaxy (also known as M104 or NGC 4594) is an unbarred spiral galaxy in the constellation Virgo. It has a bright nucleus, an unusually large central bulge, and a prominent dust in a disk inclined road. Dark dust lane and the bulge give this galaxy the appearance of a sombrero. The galaxy has an apparent magnitude of 9.0, making it easily visible with amateur telescopes. Big bulge, central supermassive black hole, and all the road dust attracted the attention of professional astronomers. What happened in the Milky Way itself. The light from the supernova reached Earth on February 23, 1987. As the first supernova discovered in 1987, it was labeled "1987a". Brightness peaked in May with an apparent magnitude of about 3 and slowly declined in the following months. This is the first opportunity for modern astronomers to see a supernova up close.

2.Galaksi Black Eye

A spiral galaxy in the constellation Coma Berenices, Messier 64, the famous "Black Eye" galaxy or the "Sleeping Beauty galaxy," has a spectacular dark band absorbing dust in front of the galaxy's bright nucleus. It was well known among amateur astronomers because of its appearance in small telescopes.

3. 2MASX J00482185-2507365 occulting pair

2MASX J00482185-2507365 occulting pair is a pair of overlapping spiral galaxies found around NGC 253, the Sculptor Galaxy. The two galaxies more distant than NGC 253, with a background galaxy, 2MASX J00482185-2507365, lying at redshift z = 0.06, and the foreground galaxy NGC located between 253 and galaxies in the background (0.0008 <0 , 06). This pair of galaxies illuminates the distribution of galactic dust beyond the visible galaxy's spiral arms. As far as heretofore unexpected dust beyond the starry limits of the arms, shows new areas for extragalactic astronomical study. The arms are dusty extend 6 times with your fingers the starry galaxies, and the image shown in silhouette against the HST and the central core of the galaxy in the background.

4. The Whirlpool Galaxy

The Whirlpool Galaxy is also known as Messier 51A, M51a, or NGC 5194, the Whirlpool Galaxy is an interacting grand-design spiral galaxy located at a distance of about 23 million light-years away in the constellation Canes Venatici.This is one of the most famous spiral galaxies in the sky. And a companion galaxy (NGC 5195) are easily observed by amateur astronomers, and the two galaxies may even be seen with binoculars. The Whirlpool Galaxy is also a popular target professional astronomers, who study to better understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.

5. Grand Spiral Galaxy

Grand Spiral Galaxy also known as NGC 123, a stunning galaxy is dominated by millions of bright stars and dark dust, caught in a vortex gravity spiral arms rotate around the center. Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lines dense interstellar dust can be seen sprinkled between them. Less visible, but detectable, are billions of dim normal stars and vast interstellar gas, together hold such high mass that they dominate the dynamics of the inner galaxy. Invisible is a greater amount of material in a form that we do not yet know - pervasive dark matter needed to explain the movement that looks beyond the galaxy.

6. Supernova 1987 A

Two decades ago, astronomers see one of the brightest stellar explosions in more than 400 years: an accursed star, called Supernova 1987a. This image shows the entire region around the supernova. The most prominent feature in the image is a ring with dozens of bright spots. A shock wave of material caused by the explosion of a slamming into regions along the ring inner regions, heating them and causing them to glow. The ring, about a light-year across, probably shed by the star about 20,000 years before it exploded. In the next few years, the entire ring will light up as absorb the full force of the accident. The ring of fire is expected to become bright enough to illuminate the star, provide astronomers with new information about how stars expel the material before the explosion. The picture was taken in December 2006 with Hubble's Advanced Camera for Surveys. (Credit: NASA, ESA, and R. Kirshner; Harvard-Smithsonian Center for Astrophysics)

7. Galaxy NGC 1512

A spiral galaxy located about 30 million light-years away toward the constellation Horologium, Galaxy NGC 1512 is bright enough to be seen with amateur telescopes. The galaxy is about 70,000 light-years across, which is almost as large as our own Milky Way galaxy. Core galaxy remarkable for its "circumnuclear" starburst ring, which is an extraordinary circle of young star group that includes several light-years in 2400. Galaxies "starbursts" are episodes of vigorous formation of new stars and are found in various galaxy environments.

8. Galaxy NGC 3370

The dusty spiral galaxy located about 98 million light-years away toward the constellation Leo, the center of NGC 3370 shows dust lanes and well illustrated with excruciating pain that specified the core. This view is NGC 3370 obtained by the Hubble Space Telescope using the Advanced Camera for surveys and is sharp enough to identify individual Cepheid variable stars in the galaxy. Cepheid variable stars are used to establish extragalactic distances. In 1994, he sypernova exploded in NGC 3370 type. (Credit: NASA, The Hubble Heritage Team and A. Riess; STScI) galaxy is about 70,000 light-years across, which is almost as large as our own Milky Way galaxy. Core galaxy remarkable for its "circumnuclear" starburst ring, which is an extraordinary circle of young star group that includes several light-years in 2400. Galaxies "starbursts" are episodes of vigorous formation of new stars and are found in various galaxy environments.

9. M81

Big and beautiful spiral galaxy M81, in the northern constellation Ursa Major, is one of the brightest galaxies visible in the skies of planet Earth. This incredible detailed view reveals a bright nucleus, a large spiral arms and sweeping cosmic dust lane with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust road runs straight through the disk, below and right of the galactic center, contrary to M81 other prominent spiral features. Errant dust lane may be firmly attached to the results of a meeting between the M81 and the smaller companion galaxy, M82. Monitoring variable stars in M81 (aka NGC 3031) has produced one of the best to determine the distance of an external galaxy - 11.8 million light-years away.

10. Hoag's Object

Not typical, types of galaxies known as a ring galaxy, the appearance of Hoag's Object has interested amateur astronomers as a common structure fascinated professionals. Is this one galaxy or two? This question was revealed in 1950 when astronomer Art Hoag extragalactic chance on this unusual object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball many red stars may be much older. Between the two is a gap that appears almost completely dark. How Hoag's Object formed remains unknown, although similar objects have now been identified and collectively labeled as a form of ring galaxy. Genesis hypotheses include galaxy collision billions of years ago and perturbative gravitational interactions involving an unusually shaped core. The photo above was taken by the Hubble Space Telescope in July 2001 reveals unprecedented details of Hoag's Object and may yield a better understanding. Hoag's Object span of about 100,000 light years and lies about 600 million light-years away toward the constellation Serpens. Incidentally, look at the gap again ring galaxy that likely lies far in the distance.

 Dwi Hartoyo, SP

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