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Proper NameNone
Bayer DesignationEta Orionis
Flamsteed Number28 Orionis
HR (BSC)1788
Right Ascension5h 24m 29s (A), 5h 24m 29s (B)
Declination-2° 23' 49" (A), -2° 23' 50" (B)
Distance977 light years
299 parsecs
MagnitudeApparent: +3.4
Absolute: -4.0
Spectral ClassB1V blue main sequence star
Optimum VisibilityDecember / January
NotesThis is a triple system, in which the central pair of stars follow an extremely close orbit, ten times closer to one another than Earth is to the Sun. This orbit takes just under eight days to complete, during which the stars' brightness dips twice, once as the companion star passes in front of the primary, and once as it passes behind.

A star system nearly a thousand light years from Earth, a little to the west of the Belt of Orion. It is an eclipsing system consisting of three blue stars orbiting one another in a regular pattern.


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