Messier 38

Messier 38
M38 open cluster, source: NOAO
Observation data (J2000.0 epoch)
Constellation	Auriga
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′
Physical characteristics
Radius	25 ly
Estimated age	220 Ma
Other designations	NGC 1912
See also: Open cluster, List of open clusters

Messier 38 (also known as M38 or NGC 1912) is an open cluster in the Auriga constellation.

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.^[1]

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.

Walter Scott Houston described its appearance as follows:^[2]

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.

Map

Components

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

References

1. ^ 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. 
2. ^ Houston, Walter Scott (2005). Deep-Sky Wonders. Sky Publishing Corporation. ISBN 1931559236. 

External links

• Messier 38, SEDS Messier pages
• Messier 38 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

See also

• Messier 36
• Messier 37

Coordinates: 05^h 28^m 42^s, +35° 51′ 18″