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> Open cluster M46 with Planetary Nebula NGC 2438 in Puppis

Open cluster M46 with Planetary Nebula NGC 2438 in Puppis

author: J.Lodriguss/Novapix

reference: a-aou24-37009

Image Size 300 DPI: 32 * 21 cm

M46 is a rich open cluster that contains a real jewel, planetary nebula NGC 2438. At 6th magnitude, M46 contains about 100 bright stars, the brightest of which is magnitude 8.7. It is about one-half degree in apparent diameter, the same size as the full moon. It is estimated to be about 300 million years old. Planetary nebula NGC 2438 is about one arc minute in diameter and shines at 10th magnitude. A planetary nebula is a shell of gas puffed off by a star late in its life cycle. Three bright stars are visible inside of the nebula, although none of them are the true central star which shed the gas. The central star in NGC 2438 has a magnitude of 17.7, so the stars visible inside of the ring are members of the cluster M46, which lies behind the planetary nebula, but along the same line of sight. The true central star of NGC 2438 is probably more than a billion years old, another indication that it is not a member of the cluster. NGC 2438, discovered by William Herschel in 1786, is located at a distance of about 2,900 light years. M46 is located about 5,400 light years away and was discovered by Charles Messier in 1771. Both cluster and planetary nebula are located in the constellation of Puppis.

Keywords for this photo:

2009 - ASTRONOMY - EVOLUTION - M46 - NGC 2437 - NGC 2438 - OPEN CLUSTER - PLANETARY NEBULA - PUPPIS - STAR - STAR CLUSTER -