Messier 51 and Dorado: Difference between pages

From Ascension Glossary
(Difference between pages)
No edit summary
 
No edit summary
 
Line 1: Line 1:
The Whirlpool Galaxy (also known as Messier 51a, M51a, or NGC 5194) is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus in the constellation [[Canes Venatici]]. It was the first galaxy to be classified as a spiral galaxy. Recently it was estimated to be 23 ± 4 million light-years from the Milky Way, but different methods yield distances between 15 and 35 million ly. [[Messier 51]] is one of the best known galaxies in the sky. The galaxy and its companion (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 for professional astronomers, who study it to further understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.
[[File:375px-Dorado IAU.svg.png|thumb|Dorado]]
What later became known as the Whirlpool Galaxy was discovered on October 13, 1773 by Charles Messier while hunting for objects that could confuse comet hunters, and was designated in Messier's catalogue as M51.Its companion galaxy, NGC 5195, was discovered in 1781 by Pierre Méchain, although it was not known whether it was interacting or merely another galaxy passing at a distance.
Dorado is a constellation in the southern sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish (Coryphaena hippurus), which is known as dorado in Portuguese, although it has also been depicted as a swordfish. Dorado is notable for containing most of the Large Magellanic Cloud, the remainder being in the constellation Mensa. The South ecliptic pole also lies within this constellation.Even though the name Dorado is not Latin but Portuguese, astronomers give it the Latin genitive form Doradus when naming its stars; they are treating it (like the adjacent constellation Argo Navis) as if it were a feminine proper name of Greek origin ending in -ō (like Io or Callisto or Argo), names that have a genitive ending in -ūs. Its first depiction in a celestial atlas was in Johann Bayer's Uranometria of 1603 where it was also named Dorado. Dorado has been represented historically as a dolphinfish and a swordfish; the latter depiction is inaccurate. It has also been represented as a goldfish.
Located within the constellation [[Canes Venatici]], M51 is found by following the easternmost star of the Big Dipper, Eta Ursae Majoris, and going 3.5° southwest. Its declination is +47°, making it a circumpolar for observers located above 43°N latitude; it reaches high altitudes throughout the northern hemisphere making it an accessible object from the early hours in winter through the end of spring season, after which observation is hindered in lower latitudes.


A black hole, surrounded by a ring of dust, is thought to exist at the heart of the spiral. The dust ring stands almost perpendicular to the relatively flat spiral nebula. Stars are usually formed in the center of the galaxy. The center part of M51 appears to be undergoing a period of enhanced star formation. The present efficiency of star formation, defined as the ratio of mass of new stars to the mass of star-forming gas, is only ~1%, quite comparable to the global value for the Milky Way and other galaxies. It is estimated that the current high rate of star formation can last no more than another 100 million years or so.  
==Deep Sky Objects==
Because Dorado contains part of the Large Magellanic Cloud, it is rich in deep sky objects. The Large Magellanic Cloud, 1,000 light-years in diameter, is a satellite galaxy of the Milky Way, located at a distance of 179,000 light-years. It has been deformed by its gravitational interactions with the larger Milky Way. In 1987, it became host to SN 1987A, the first supernova of 1987 and the closest since 1604.This 25,000 light-year wide galaxy contains over 10,000 million stars. All coordinates given are for Epoch J2000.0.
* NGC 1566 is an intermediate spiral galaxy.[5]NGC 1566 (RA 04h 20m 00s Dec -56° 56.3′) Skyview image is a face-on spiral galaxy. It gives its name to the NGC 1566 Group of galaxies.NGC 1755 (RA 04h 55m 13s Dec -68° 12.2′) Skyview image is a globular cluster.


Induced spiral structure in the larger galaxy is not the only effect of the interaction. Significant compression of hydrogen gas occurs that leads to the development of starbirth regions. In pictures of M51 these show up as the bright blue 'knots' throughout the spiral arms.A secondary ring crosses the primary ring on a different axis, a phenomenon that is contrary to expectations. A pair of ionization cones extend from the axis of the main dust ring.
* NGC 1763 (RA 04h 56m 49s Dec -68° 24.5′) Skyview image is a bright nebula associated with three type B stars.NGC 1820 (RA 05h 04m 02s Dec -67° 15.9′) Skyview image is an open cluster.
* NGC 1850 (RA 05h 08m 44s Dec -68° 45.7′) Skyview image is a globular cluster.


The Whirlpool Galaxy is the brightest galaxy in the M51 Group, a small group of galaxies that also includes M63 (the [[Sunflower Galaxy]]), NGC 5023, and NGC 5229. This small group may actually be a subclump at the southeast end of a large, elongated group that includes the M101 Group and the NGC 5866 Group, although most group identification methods and catalogs identify the three groups as separate entities.<ref>[http://en.wikipedia.org/wiki/Whirlpool_Galaxy Whirlpool Galaxy]]</ref>
* NGC 1854 (RA 05h 09m 19s Dec -68° 50.8′) Skyview image is a globular cluster.NGC 1869 (RA 05h 13m 56s Dec -67° 22.8′) Skyview image is an open cluster.NGC 1901 (RA 05h 18m 15s Dec -68° 26.2′) Skyview image is an open cluster.


* NGC 1910 (RA 05h 18m 43s Dec -69° 13.9′) Skyview image is an open cluster.NGC 1936 (RA 05h 22m 14s Dec -67° 58.7′) Skyview image is a bright nebula and is one of four NGC objects in close proximity, the others being NGC 1929, NGC 1934 and
* NGC 1935.NGC 1978 (RA 05h 28m 36s Dec -66° 14.0′) Skyview image is an open cluster.NGC 2002 (RA 05h 30m 17s Dec -66° 53.1′) Skyview image is an open cluster.


* NGC 2027 (RA 05h 35m 00s Dec -66° 55.0′) Skyview image is an open cluster.


==HGS Session References==
* NGC 2032 (RA 05h 35m 21s Dec -67° 34.1′) (Seagull Nebula) Skyview image is a nebula complex that contains four separate NGC designations:
* NGC 2029, NGC 2032, NGC 2035 and NGC 2040.NGC 2080, also called the "Ghost Head Nebula", is an emission nebula that is 50 light-years wide in the Large Magellanic Cloud. It is named for the two distinct white patches that it possesses, which are regions of recent star formation. The western portion is colored green from doubly-ionized oxygen, the southern portion is red from hydrogen alpha emissions, and the center region is colored yellow from both oxygen and hydrogen emissions. The western white patch, A1, has one massive, recently formed star inside. The eastern patch, A2, has several stars hidden in its dust.[4]NGC 2070 is a nebula in the Large Magellanic Cloud, also known as the Tarantula Nebula and named for its spiderlike shape. It is also designated 30 Doradus, as it is visible to the naked eye as a slightly out-of-focus star. Larger than any nebula in the Milky Way at 1000 light-years in diameter, it is also brighter, because it is illuminated by a cluster of stars, R136. The illuminating stars are supergiants.


 
* NGC 2164 (RA 05h 58m 53s Dec -68° 30.9′) Skyview image is a globular cluster.N44 is a superbubble in the Large Magellanic Cloud that is 1,000 light-years wide. Its overall structure is shaped by the 40 hot stars towards its center. Within the superbubble of N44 is a smaller bubble catalogued as N44F. It is approximately 35 light-years in diameter and is shaped by an incredibly hot star at its center, which has a stellar wind speed of 7 million kilometers per hour. N44F also features dust columns with probable star formation hidden inside.
 
==References==
 
 
 
 
<references/>
 
 
 
 
Found in HGS Manual on Page 108
 
 
 
 
Found in HGS Manual on Page 115
 
[[Category: Ascension]]
[[Category: HGS Manual]]

Revision as of 20:55, 23 March 2015

Dorado

Dorado is a constellation in the southern sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish (Coryphaena hippurus), which is known as dorado in Portuguese, although it has also been depicted as a swordfish. Dorado is notable for containing most of the Large Magellanic Cloud, the remainder being in the constellation Mensa. The South ecliptic pole also lies within this constellation.Even though the name Dorado is not Latin but Portuguese, astronomers give it the Latin genitive form Doradus when naming its stars; they are treating it (like the adjacent constellation Argo Navis) as if it were a feminine proper name of Greek origin ending in -ō (like Io or Callisto or Argo), names that have a genitive ending in -ūs. Its first depiction in a celestial atlas was in Johann Bayer's Uranometria of 1603 where it was also named Dorado. Dorado has been represented historically as a dolphinfish and a swordfish; the latter depiction is inaccurate. It has also been represented as a goldfish.

Deep Sky Objects

Because Dorado contains part of the Large Magellanic Cloud, it is rich in deep sky objects. The Large Magellanic Cloud, 1,000 light-years in diameter, is a satellite galaxy of the Milky Way, located at a distance of 179,000 light-years. It has been deformed by its gravitational interactions with the larger Milky Way. In 1987, it became host to SN 1987A, the first supernova of 1987 and the closest since 1604.This 25,000 light-year wide galaxy contains over 10,000 million stars. All coordinates given are for Epoch J2000.0.

  • NGC 1566 is an intermediate spiral galaxy.[5]NGC 1566 (RA 04h 20m 00s Dec -56° 56.3′) Skyview image is a face-on spiral galaxy. It gives its name to the NGC 1566 Group of galaxies.NGC 1755 (RA 04h 55m 13s Dec -68° 12.2′) Skyview image is a globular cluster.
  • NGC 1763 (RA 04h 56m 49s Dec -68° 24.5′) Skyview image is a bright nebula associated with three type B stars.NGC 1820 (RA 05h 04m 02s Dec -67° 15.9′) Skyview image is an open cluster.
  • NGC 1850 (RA 05h 08m 44s Dec -68° 45.7′) Skyview image is a globular cluster.
  • NGC 1854 (RA 05h 09m 19s Dec -68° 50.8′) Skyview image is a globular cluster.NGC 1869 (RA 05h 13m 56s Dec -67° 22.8′) Skyview image is an open cluster.NGC 1901 (RA 05h 18m 15s Dec -68° 26.2′) Skyview image is an open cluster.
  • NGC 1910 (RA 05h 18m 43s Dec -69° 13.9′) Skyview image is an open cluster.NGC 1936 (RA 05h 22m 14s Dec -67° 58.7′) Skyview image is a bright nebula and is one of four NGC objects in close proximity, the others being NGC 1929, NGC 1934 and
  • NGC 1935.NGC 1978 (RA 05h 28m 36s Dec -66° 14.0′) Skyview image is an open cluster.NGC 2002 (RA 05h 30m 17s Dec -66° 53.1′) Skyview image is an open cluster.
  • NGC 2027 (RA 05h 35m 00s Dec -66° 55.0′) Skyview image is an open cluster.
  • NGC 2032 (RA 05h 35m 21s Dec -67° 34.1′) (Seagull Nebula) Skyview image is a nebula complex that contains four separate NGC designations:
  • NGC 2029, NGC 2032, NGC 2035 and NGC 2040.NGC 2080, also called the "Ghost Head Nebula", is an emission nebula that is 50 light-years wide in the Large Magellanic Cloud. It is named for the two distinct white patches that it possesses, which are regions of recent star formation. The western portion is colored green from doubly-ionized oxygen, the southern portion is red from hydrogen alpha emissions, and the center region is colored yellow from both oxygen and hydrogen emissions. The western white patch, A1, has one massive, recently formed star inside. The eastern patch, A2, has several stars hidden in its dust.[4]NGC 2070 is a nebula in the Large Magellanic Cloud, also known as the Tarantula Nebula and named for its spiderlike shape. It is also designated 30 Doradus, as it is visible to the naked eye as a slightly out-of-focus star. Larger than any nebula in the Milky Way at 1000 light-years in diameter, it is also brighter, because it is illuminated by a cluster of stars, R136. The illuminating stars are supergiants.
  • NGC 2164 (RA 05h 58m 53s Dec -68° 30.9′) Skyview image is a globular cluster.N44 is a superbubble in the Large Magellanic Cloud that is 1,000 light-years wide. Its overall structure is shaped by the 40 hot stars towards its center. Within the superbubble of N44 is a smaller bubble catalogued as N44F. It is approximately 35 light-years in diameter and is shaped by an incredibly hot star at its center, which has a stellar wind speed of 7 million kilometers per hour. N44F also features dust columns with probable star formation hidden inside.
Retrieved from "https://ascensionglossary.com/index.php?title=Messier_51&oldid=12070"