M38 open cluster, source: NOAO
|Observation data (J2000.0 epoch)|
|Right ascension||5h 28m 42s|
|Declination||+35° 51′ 18″|
|Distance||4.2 kly (1.3 kpc)|
|Apparent magnitude (V)||7.4|
|Apparent dimensions (V)||21′|
|Estimated age||220 Ma|
|Other designations||NGC 1912|
It was discovered by Giovanni Batista Hodierna before 1654 and independently found by Le Gentil in 1749. M36 and M37, also discovered by Hodierna, are grouped together with M38 at a distance of about 3,420 light years away from Earth.
The cluster's brightest stars form a pattern resembling the Greek letter Pi or, according to Webb, an "oblique cross." At its distance of 4,200 light years, its angular diameter of about 20' corresponds to about 25 light years, similar to that of its more distant neighbor M37. It is of intermediate age (about 220 million years, according to Sky Catalog 2000) and features a yellow giant of apparent magnitude +7.9 and spectral type G0 as its brightest member. This corresponds to an absolute magnitude of -1.5, or a luminosity of 900 Suns. For comparison, the Sun would appear as a faint magnitude +15.3 star from the distance of M38.
Photographs usually show a departure from circularity, a feature quite evident to visual observers. Older reports almost always mention a cross shape, which seems more pronounced with small instruments. A view with a 24-inch reflector on a fine Arizona night showed the cluster as irregular, and the host of stars made fruitless any effort to find a geometrical figure.
|NAME||Right ascension||Declination||Spectral type|
|HD 35519||05h 26m 54.3176s||+35° 27' 26.181||K2|
|NGC 1912 HOAG 2||B5II-III|
|NGC 1912 HOAG 3|
|NGC 1912 HOAG 4||05h 28m 35.39s||+35° 52' 51.2||A0V|
|NGC 1912 HOAG 5||05h 28m 50.73s||+35° 46' 47.2||A0Vn|
|NGC 1912 HOAG 6||05h 28m 10.46s||+35° 55' 26.0||A0:V|
|NGC 1912 HOAG 7||05h 28m 34.25s||+35° 53' 29.7||A2V|
|NGC 1912 HOAG 11|
|NGC 1912 HOAG 19||K2IIIb|
|NGC 1912 HOAG 104||G5III|
|NGC 1912 SS G2|
|NGC 1912 HOAG 128||K0III|
|NGC 1912 SS G4||A5:V|
|NGC 1912 HOAG 153||K0V|
|NGC 1912 SS G3||A3V|
|NGC 1912 HOAG 160||K1IV|
|NGC 1912 HOAG 161||G5V|
|NGC 1912 HOAG 171||G7IV|
|NGC 1912 HOAG 172|
- 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: 1349. arXiv:0710.2900. Bibcode:2007PASP..119.1349M. doi:10.1086/524414.
- Houston, Walter Scott (2005). Deep-Sky Wonders. Sky Publishing Corporation. ISBN 1-931559-23-6.
- Messier 38, SEDS Messier pages
- Messier 38 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
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