Messier 101

Messier 101 (also known as NGC 5457 , Pinwheel Galaxy or Firewheel Galaxy ) is a spiral galaxy with dimensions of 28.8 '× 26.9' and an apparent magnitude of 7.5 mag in the constellation of Great Bear . Their distance is around 16 million light years , their diameter 170,000 light years .

Halton Arp organized his catalog of unusual galaxies into groups according to purely morphological criteria. This galaxy belongs to the class spiral galaxies with a pronounced arm (Arp catalog) . M 101 has five prominent companion galaxies: NGC 5204 , NGC 5474 , NGC 5477 , NGC 5585, and Holmberg IV .

Observation history

Photograph with the inscription of some striking celestial objects in the vicinity of the galaxy M 101. In the lower right quarter you can see the end of the drawbar of the Big Dipper in the constellation Big Bear with the stars Mizar, Alkor and Alkaid. In the lower left quarter there is the constellation Bärenhüter (Bootes) , and in the upper part of the picture is the constellation Dragon .

Messier 101 was discovered on March 27, 1781 by the French astronomer Pierre Méchain , who communicated the position of the object to Charles Messier. Messier added the stationary object that looked like a comet to the naked eye or with a short exposure time in the final version of his catalog in the same year. Various bright nodes of M 101, which are H-II areas and / or star clouds, were later included in the NGC under separate entries .

Individual objects in M101

Name of the object	Right ascension	declination	m _V	Explorer	Discovery date
HK 461 = HK 465	140223.914 ^h 02 ^m 23.9 ^s	2541747+ 54 ° 17 ′ 47 ″
NGC 5449	140228.114 ^h 02 ^m 28.1 ^s	2541950+ 54 ° 19 ′ 50 ″	14th	Bindon Blood Stoney	April 27, 1851
NGC 5447 = NGC 5450	140228.314 ^h 02 ^m 28.3 ^s	2541632+ 54 ° 16 ′ 32 ″	13.5	Bindon Blood Stoney	April 27, 1851
NGC 5451	140236.614 ^h 02 ^m 36.6 ^s	2542149+ 54 ° 21 ′ 49 ″	14th	Bindon Blood Stoney	April 27, 1851
HK 371	140254.314 ^h 02 ^m 54.3 ^s	2541626+ 54 ° 16 ′ 26 ″	13.8
NGC 5453	140256.714 ^h 02 ^m 56.7 ^s	2541820+ 54 ° 18 ′ 20 ″	13.8	Bindon Blood Stoney	April 27, 1851
NGC 5455	140301.214 ^h 03 ^m 01.2 ^s	2541427+ 54 ° 14 ′ 27 ″	13	Bindon Blood Stoney	April 27, 1851
HK 309 = HK 314	140302.214 ^h 03 ^m 02.2 ^s	2542003+ 54 ° 20 ′ 03 ″	13.9
NGC 5458	140312.514 ^h 03 ^m 12.5 ^s	2541755+ 54 ° 17 ′ 55 ″	14th	Bindon Blood Stoney	April 27, 1851
HK 103	140327.214 ^h 03 ^m 27.2 ^s	2541845+ 54 ° 18 ′ 45 ″
HK 70	140330.614 ^h 03 ^m 30.6 ^s	2542038+ 54 ° 20 ′ 38 ″
HK 60	140332.414 ^h 03 ^m 32.4 ^s	2541721+ 54 ° 17 ′ 21 ″
HK 59	140333.814 ^h 03 ^m 33.8 ^s	2542026+ 54 ° 20 ′ 26 ″
NGC 5461	140339.714 ^h 03 ^m 39.7 ^s	2541856+ 54 ° 18 ′ 56 ″	14th	William Herschel	April 14, 1789
HK 20	140349.414 ^h 03 ^m 49.4 ^s	2542738+ 54 ° 27 ′ 38 ″
NGC 5462	140353.514 ^h 03 ^m 53.5 ^s	2542202+ 54 ° 22 ′ 02 ″	13.5	William Herschel	April 14, 1789
H 1216	140412.414 ^h 04 ^m 12.4 ^s	2542527+ 54 ° 25 ′ 27 ″
NGC 5471	140429.114 ^h 04 ^m 29.1 ^s	2542349+ 54 ° 23 ′ 49 ″	14.7	Heinrich d'Arrest	August 22, 1863

On February 28, 2006, NASA and ESA released a very impressive image, the largest and most detailed image of a galaxy, made with the help of Hubble . The picture was composed of over 51 pictures.

On August 24, 2011, was in M101 supernova type Ia discovered that the designation SN 2011fe received.