Phi¹ Orionis is a binary star system in the constellation Orion, positioned less than a degree to the south of

Meissa Meissa , designated Lambda Orionis (λ Orionis, abbreviated Lambda Ori, λ Ori) is a star in the constellation of Orion. It is a multiple star approximately away with a combined apparent magnitude of 3.33. The main components are ...

. It is visible to the naked eye with an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 4.42. The distance to this system, based upon an annual parallax shift of 3.0 mas, is around 1,090 light-years. This is a single-lined spectroscopic binary star system with an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 3,068 days and an

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.22. It is a member of the young Lambda Orionis cluster and is roughly 7 million years old. The primary component is a B-type

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

with a stellar classification of B0 III. It has over 15 times the mass of the Sun and around 6.3 times the Sun's radius. Nothing is known about the secondary companion. It does not contribute a significant amount of light to the combined spectrum.

References

External links

* {{DEFAULTSORT:Phi1 Orionis Spectroscopic binaries B-type giants Orionis, Phi Orion (constellation) Durchmusterung objects Orionis, 37 036822 026176

1876 Events January–March * January 1 ** The Reichsbank opens in Berlin. ** The Bass Brewery Red Triangle becomes the world's first registered trademark symbol. * February 2 – The National League of Professional Base Ball Clubs is ...