Messier 47

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Messier 47
M47a.jpg
Observation data (J2000.0 epoch)
Right ascension 07h 36.6m
Declination -14° 30′
Distance 1.6 kly (490 Pc)
Apparent magnitude (V) 4.2
Apparent dimensions (V) 30.0′
Physical characteristics
Radius 6
Estimated age 78 million years
Other designations NGC 2422, M47
See also: Open cluster, List of open clusters

Messier 47 (Messier Object 47, M47, or NGC 2422) is an open cluster in the constellation Puppis. It was discovered by Giovanni Batista Hodierna before 1654 and independently discovered by Charles Messier on February 19, 1771. It was later independently discovered again, under the current name NGC 2422.

There is actually no cluster in the position indicated by Messier, which he expressed in terms of its right ascension and declination with respect to the star 2 Puppis. However, if the signs of Messier's coordinate differences are changed, the position matches that of NGC 2422.[1] Until the equivalency of M47 with NGC2422 was found, M47 was considered a lost Messier Object. The discovery that M47 and NGC2422 were the same cluster only came in 1959 with a realization by Canadian astronomer T. F. Morris.[2]

M47 is at a distance of about 1,600 light-years from Earth with an estimated age of about 78 million years.[2] There are about 50 stars in this cluster,[2] the brightest one being of magnitude +5.7. M47 is located relatively close in the sky to Messier 46, which is much older and much further away.[2]

References[edit]

  1. ^ Houston, Walter Scott (2005). Deep-Sky Wonders. Sky Publishing Corporation. ISBN 1-931559-23-6. 
  2. ^ a b c d "The hot blue stars of messier 47". ScienceDaily. 17 December 2014. 

External links[edit]

Coordinates: Sky map 07h 36.6m 00s, −14° 30′ 00″