Omicron Puppis (ο Puppis) is candidate binary star system in the southern constellation of Puppis. It is visible to the naked eye, having a combined

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 +4.48. Based upon an annual parallax shift of 2.30 mas as seen from Earth, it is located roughly 1,400 light years from the Sun. This is a suspected close spectroscopic binary system. The

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

varies with a periodicity of 28.9 days, and a helium emission component shows a radial velocity variation that matches the period. The properties indicate it may be a φ Per-like system with a

Be star Be stars are a heterogeneous set of stars with B spectral types and emission lines. A narrower definition, sometimes referred to as ''classical Be stars'', is a non-supergiant B star whose spectrum has, or had at some time, one or more Balmer e ...

primary and a hot subdwarf companion of type sdO. If this is the case, then the pair have a circular orbit with a

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

that matches the variability. The close-orbiting pair may have undergone interaction in the past, leaving the subdwarf stripped down and the primary star spinning rapidly. ο Puppis is slightly variable. The

General Catalogue of Variable Stars The General Catalogue of Variable Stars (GCVS) is a list of variable stars. Its first edition, containing 10,820 stars, was published in 1948 by the Academy of Sciences of the USSR and edited by B. V. Kukarkin and P. P. Parenago. Second and thi ...

lists it as a possible

with a magnitude range of 4.43 - 4.46. The International Variable Star Index classifies it as a

Lambda Eridani variable A Lambda Eridani Variable is a class of Be stars that show small amplitude variations of a few hundredths of a magnitude. The variations are highly regular with periods between 0.5 and 2.0 days, and they were initially described as periodic Be star ...

Naming

The correct Bayer designation for ο Puppis has been debated.

Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good ...

assigned one Greek letter sequence for the bright stars of

Argo Navis Argo Navis (the Ship Argo), or simply Argo, is one of the 48 Ptolemy's constellations, now a grouping of three IAU constellations. It is formerly a single large constellation in the southern sky. The genitive is "Argus Navis", abbreviated "Arg" ...

. These Lacaille designations are now shared across the three modern constellations of

Carina Carina may refer to: Places Australia * Carina, Queensland, a suburb in Brisbane * Carina Heights, Queensland, a suburb in Brisbane * Carina, Victoria, a locality in Mildura Serbia * Carina, Osečina, a village in the Kolubara District ...

, Puppis, and Vela so that the same Greek letter is not usually found in more than one of the three. However, ο (omicron) is commonly used for stars in both Puppis and Vela. Some authors contend that Lacaille actually assigned a Latin lower case 'o' to this star, while others suggest that ο Velorum should actually be a lower case 'o'. In the ''Coelum Australe Stelliferum'' itself, this star is labelled (Latin) o Argus in puppi (Pouppe du Navire in the French edition), while ο Velorum is labelled ο (omicron) Argus (du Navire in the French edition). In

Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...

, (), meaning '' Bow and Arrow'', refers to an asterism consisting of ο Puppis, δ Canis Majoris, η Canis Majoris, HD 63032,

HD 65456 χ Puppis, Latinised as Chi Puppis, is a single star in the southern constellation of Puppis. It has a white hue and is faintly visible to the eye at night with an apparent visual magnitude of 4.79. The star is located at a distance o ...

, k Puppis, ε Canis Majoris, κ Canis Majoris and π Puppis. Consequently, ο Puppis itself is known as (, en, the Fifth Star of Bow and Arrow.)AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日
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References

{{DEFAULTSORT:Omicron Puppis B-type subgiants Lambda Eridani variables Be stars Puppis, Omicron Puppis Durchmusterung objects 063462 038070 3045