|Observation data (J2000.0 epoch)|
|Right ascension||07h 41.8m|
|Distance||5.4 kly (1.7 kPc)|
|Apparent magnitude (V)||6.1|
|Apparent dimensions (V)||27.0′|
|Estimated age||300 million years|
planetary nebula NGC 2438
|Other designations||NGC 2437|
Messier 46 (also known as M46 or NGC 2437) is an open cluster in the constellation of Puppis. It was discovered by Charles Messier in 1771. Dreyer described it as "very bright, very rich, very large." M46 is about 5,500 light-years away. There are an estimated 500 stars in the cluster, and it is thought to be some 300 million years old.
The 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. It is an example of a superimposed pair possibly similar to that of NGC 2818. On the other hand, the illuminating star of the bipolar Calabash Nebula shares the radial velocity and proper motion of Messier 46, and is at the same distance, so is a bona fide member of the open cluster.
- Majaess D. J.; Turner D.; Lane D. (2007). "In Search of Possible Associations between Planetary Nebulae and Open Clusters". Publications of the Astronomical Society of the Pacific. 119 (862): 1349. arXiv:0710.2900. Bibcode:2007PASP..119.1349M. doi:10.1086/524414.
- "The hot blue stars of messier 47". ScienceDaily. 17 December 2014.
- Kiss, L. L.; Szabó, Gy. M.; Balog, Z.; Parker, Q. A.; et al. (2008). "AAOmega radial velocities rule out current membership of the planetary nebula NGC 2438 in the open cluster M46". Monthly Notices of the Royal Astronomical Society. 391: 399. arXiv:0809.0327. Bibcode:2008MNRAS.391..399K. doi:10.1111/j.1365-2966.2008.13899.x.
- Mermilliod, J.-C.; Clariá, J. J.; Andersen, J.; Piatti, A. E.; et al. (2001). "Red giants in open clusters. IX. NGC 2324, 2818, 3960 and 6259". Astronomy and Astrophysics. 375: 30. Bibcode:2001A&A...375...30M. CiteSeerX 10.1.1.30.7545. doi:10.1051/0004-6361:20010845.
- Vickers S.B.; Frew D.J.; Parker Q.A.; Bojicic I.S. (2015). "New light on Galactic post-asymptotic giant branch stars - I. First distance catalogue". Monthly Notices of the Royal Astronomical Society. 447 (2): 1673. arXiv:1403.7230. Bibcode:2015MNRAS.447.1673V. doi:10.1093/mnras/stu2383.
- Messier 46, SEDS Messier pages
- Messier 46, Amateur Astronomer Image – Waid Obseratory
- Dark Atmospheres Photography – M46 w/ NGC 2438 detail
- NASA Astronomy Picture of the Day: M46 and NGC 2438: Young and Old (5 March 1999)
- NASA Astronomy Picture of the Day: Stars Young and Old (26 March 2009) - featuring M46
- NASA Astronomy Picture of the Day: M64 Plus Two (17 April 2015)
- Messier 46 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- Media related to Messier 46 at Wikimedia Commons