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Proper NameNone
Bayer Designationm Orionis
Flamsteed Number23 Orionis
HR (BSC)1770
Right Ascension5h 22m 50s
Declination+3° 32' 40"
Distancec.1,200 light years
c.400 parsecs
MagnitudeApparent: +5.0
Absolute: -3.4
Spectral ClassB1V blue main sequence star
Optimum VisibilityDecember / January
NotesThe m Orionis system consists of an orbiting pair of hot blue main sequence stars, with the primary being more than fifteen times as luminous as its companion. The two are widely separated from one another, and their mutual orbit can carry them nearly 10,000 AU apart.

A faint blue star in Orion, lying to the south of Bellatrix, the Hunter's western shoulder. With a visual magnitude of +4.99 it falls on the limit of naked eye visibility, though it has many times the luminosity of the Sun.

More than a thousand light years from the Solar System, it lies on the fringes of the Orion Molecular Cloud, the vast dark mass of material that lies behind much of the familiar form of Orion. m Orionis is a binary system, in which the primary blue star has a companion, also of the blue dwarf type.


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