Messier 38

Messier 38

M38 open cluster
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 13 ly
Estimated age 220 Ma
Other designations NGC 1912

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

See also

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. Bibcode:2007PASP..119.1349M. arXiv:0710.2900 Freely accessible. doi:10.1086/524414.
  2. ↑ Houston, Walter Scott (2005). Deep-Sky Wonders. Sky Publishing Corporation. ISBN 1-931559-23-6.

Coordinates: 05h 28m 42s, 35° 51′ 18″

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