ε Monocerotis, Latinised as Epsilon Monocerotis, is the

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

of a

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

system in the equatorial

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Monoceros Monoceros ( Greek: , "unicorn") is a faint constellation on the celestial equator. Its definition is attributed to the 17th-century cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the s ...

. Its location is a guide for sky navigation toward the Rosette Nebula. The white-hued primary component has a

stellar classification In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...

of A5 IV, suggesting it is an aging

subgiant star A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution of ...

. Its apparent magnitude is 4.39 and it is approximately 122 light years away based on parallax. It is reportedly a spectroscopic binary with a period around 331 days.Vizier catalog entry
/ref> The B component, at a separation of around 12.3", is a yellow-white hued

F-type main-sequence star An F-type main-sequence star (F V) is a main-sequence, hydrogen-fusing star of spectral type F and luminosity class V. These stars have from 1.0 to 1.4 times the mass of the Sun and surface temperatures between 6,000 and 7,600 K.Tables ...

of class F5 V and an apparent magnitude of 6.72.

References

{{DEFAULTSORT:Epsilon Monocerotis A-type subgiants F-type main-sequence stars Binary stars Monoceros Monocerotis, Epsilon BD+04 1236 Monocerotis, 08 044769 030419 2298