|Observation data (J2000.0 epoch)|
|Right ascension||07h 44m 30.0s|
|Declination||−23° 51′ 24″|
|Distance||3.38 kly (1.037 kpc)|
|Apparent magnitude (V)||6.2|
|Apparent dimensions (V)||10′|
|Estimated age||387.3 Myr|
|Other designations||Cl 160, NGC 2447, OCl 649.0 |
Messier 93 or M93, also known as NGC 2447, is an open cluster in the constellation Puppis. It was discovered by Charles Messier then added to his catalogue of comet-like objects on March 20, 1781. Caroline Herschel, the younger sister of William Herschel, independently discovered M93 in 1783, thinking it had not yet been catalogued by Messier. Walter Scott Houston described its appearance as follows:
Some observers mention the cluster as having the shape of a starfish. With a fair-sized telescope, this is its appearance on a dull night, but [a four-inch refractor] shows it as a typical star-studded galactic cluster.
M93 is at a distance of about 3,380 light years from Earth and has a spatial radius of some 5 light years, a tidal radius of ±2.3 ly, 13.1 and a core radius of 4.2 ly. Its age is estimated at 387.3 million years. The cluster is positioned nearly on the galactic plane and it is following an orbit that varies between 28–29 kly (8.5–8.9 kpc) from the Galactic Center over a period of ±7.9 Myr. 242.7
54 variable stars have been found in M93, including one slowly pulsating B-type star, one rotating ellipsoidal variable, seven Delta Scuti variables, six Gamma Doradus variables, and one hybrid δ Sct/γ Dor pulsator. Four spectroscopic binary systems in M93 include a yellow straggler component.
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- SEDS: Open Star Cluster M93
- Messier 93 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- Gray, Meghan; Zarnecki, John. "M93 – Open Cluster". Deep Space Videos. Brady Haran. Retrieved 2018-12-05.