Messier Index/M46

Messier 46 280px J2000.0 II,2,r 07h 41.8m −14° 49′ 5.4 kly 1.7 kPc 6.1 27.0′ 15 300 million years contains superimposed planetary nebula w:NGC 2438 NGC 2437 Messier 46 (also known as M 46 or NGC 2437) is an w:open cluster in the w:constellation of w:Puppis. It was discovered by w:Charles Messier in w:1771. Dreyer described it as "very bright, very rich, very large." M46 is about 5,500 w:light-years away with an estimated age on the order of several 100 million years.Majaess D. J., Turner D., Lane D. (2007). In Search of Possible Associations between Planetary Nebulae and Open Clusters, PASP, 119, 1349 The w:planetary nebula NGC 2438 appears to lie within the cluster near its northern edge (the faint smudge at the top center of the image), but it is most likely unrelated since it does not share the cluster's radial velocity.Kiss, L. L., Szabó, Gy. M., Balog, Z., Parker, Q. A., Frew, D. J. (2008). AAOmega radial velocities rule out current membership of the planetary nebula NGC 2438 in the open cluster M46, MNRAS The case is yet another example of a superposed pair, joining the famed case of w:NGC 2818. Mermilliod, J.-C., Clariá, J. J., Andersen, J., Piatti, A. E., Mayor, M. (2001). Red giants in open clusters. IX. NGC 2324, 2818, 3960 and 6259, A&A M46 is about a degree east of M47 in the sky, so the two fit well in a binocular or wide-angle telescope field. References External links Messier 46, SEDS Messier pages Messier 46, Amateur Astronomer Image - Waid Obseratory