Messier 38

Messier 38
M38 open cluster
Observation data (J2000.0 epoch)
Constellation Auriga
Right ascension 5h 28m 42s
Declination +35° 51′ 18″
Distance (1.066 kpc (3,480 ly)[1])
Apparent magnitude (V) 7.4
Apparent dimensions (V) 21′
Physical characteristics
Radius 4pc. (13 ly.)
Estimated age 290 Ma
Other designations NGC 1912

Messier 38 (also known as M38 or NGC 1912) is an open cluster in the constellation of Auriga. It was discovered by Giovanni Batista Hodierna before 1654 and independently found by Le Gentil in 1749. Open cluster M36 and M37, also discovered by Hodierna, and often grouped together with M38.[2] Distance is about 1.066 kpc (3,480 ly) 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 1066 pc., its angular diameter of about 20 arc minutes corresponds to about 4.0 parsecs (13 light years), similar to that of its more distant neighbor M37. It is of intermediate age at about 290 million years[1]. From the population of about 100 stars[3], this open cluster features a prominent yellow giant with the 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.

Descriptions

Walter Scott Houston described its appearance as follows:[4]

"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."

Components

Map
NAMERight
ascension		DeclinationSpectral
Type
HD 3551905h 26m 54.32s+35° 27' 26.2 K2
NGC 1912 HOAG 2B5II-III
NGC 1912 HOAG 3
NGC 1912 HOAG 405h 28m 35.39s+35° 52' 51.2 A0V
NGC 1912 HOAG 505h 28m 50.73s+35° 46' 47.2 A0Vn
NGC 1912 HOAG 605h 28m 10.46s+35° 55' 26.0 A0:V
NGC 1912 HOAG 705h 28m 34.25s+35° 53' 29.7 A2V
NGC 1912 HOAG 11
NGC 1912 HOAG 19K2IIIb
NGC 1912 HOAG 104G5III
NGC 1912 SS G2
NGC 1912 HOAG 128K0III
NGC 1912 SS G4A5:V
NGC 1912 HOAG 153K0V
NGC 1912 SS G3A3V
NGC 1912 HOAG 160K1IV
NGC 1912 HOAG 161G5V
NGC 1912 HOAG 171G7IV
NGC 1912 HOAG 172

See also

References

  1. 1 2 3 "WEBDA page for open cluster NGC 1912". Department of Theoretical Physics and Astrophysics of the Masaryk University. Retrieved 18 February 2018.
  2. ↑ 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.
  3. ↑ "WEBDA page Lynga catalogue data". Department of Theoretical Physics and Astrophysics of the Masaryk University. Retrieved 18 February 2018.
  4. ↑ 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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