Messier 47
Encyclopedia
Open Cluster M47 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.
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.
M47 is at a distance of about 1,600 light-year
s from Earth
with an estimated age of about 78 million years. There are about 50 star
s in this cluster, the brightest one being of magnitude
+5.7.
Open cluster
An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist...
in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Puppis
Puppis
Puppis is a constellation in the southern sky. Its name is the Latin word for the poop deck of a ship, and Puppis represents the deck of the ship and its deckhouses...
. It was discovered by Giovanni Batista Hodierna before 1654 and independently discovered by Charles Messier
Charles Messier
Charles Messier was a French astronomer most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 110 "Messier objects"...
on February 19, 1771.
There is actually no cluster in the position indicated by Messier, which he expressed in terms of its right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
and declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
with respect to the star 2 Puppis
K Puppis
k Puppis is a Bayer designation given to an optical double star in the constellation Puppis, the two components being k1 Puppis and k2 Puppis. Note that the designation here is "k" not "kappa" as some astronomers teach. Many of Puppis' stellar designations are English labels...
. However, if the signs of Messier's coordinate differences are changed, the position matches that of NGC 2422.
M47 is at a distance of about 1,600 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
with an estimated age of about 78 million years. There are about 50 star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s in this cluster, the brightest one being of magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
+5.7.
External links
- Messier 47, SEDS Messier pages
- Messier 47 Amateur Image - Waid Observatory