omicron Velorum
{{Short description|Variable star in the constellation Vela}}
{{Starbox begin
| name = ο Velorum
}}
{{Starbox image
| image=
{{Location mark
|image=Vela constellation map.svg|alt=|float=center|width=280
|label=|position=right
|mark=Red circle.svg|mark_width=12|mark_link=ο Vel
|x=731|y=608
}}
|caption=Location of ο Velorum (circled)
}}
{{Starbox observe
| epoch = J2000.0
| constell = Vela
| dec = {{DEC|-52|55|18.8002}}
| appmag_v = +3.60 {{nowrap|(3.57{{snd}}3.63)}}
}}
{{Starbox character
| variable = SPB
}}
{{Starbox astrometry
| radial_v = {{Val|+16.1|0.7}}
| parallax = 6.61
| p_error = 0.35
}}
{{Starbox detail
| rotational_velocity = {{val|9|5}}
| temperature = {{val|16,200|700|fmt=commas}}
| metal_fe =
}}
{{Starbox catalog
| names=CPD−52°1583, FK5 1227, HD 74195, HIP 42536, HR 3447, SAO 236164
}}
{{Starbox reference
| Simbad = Omicron+Velorum
}}
{{Starbox end}}
Omicron Velorum (ο Vel, ο Velorum) is a star in the constellation Vela. It is the brightest member of the loose naked eye open cluster IC 2391, also known as the ο Velorum Cluster.
File:OmicronVelLightCurve.png for Omicron Velorum, plotted from TESS data]]
Omicron Velorum is a blue-white B-type star with a mean apparent magnitude of +3.60. It is probably a main sequence object, but has also been classified as a subgiant or giant. It is approximately 495 light years from Earth.
Alan William James Cousins discovered that ο Velorum is a variable star in 1959. A slowly pulsating B-type star, it ranges between magnitudes 3.57 and 3.63 over 2.8 days.
The correct Bayer designation for ο Velorum has been debated. Lacaille assigned one Greek letter sequence for the bright stars of Argo Navis. These Lacaille designations are now shared across the three modern constellations of Carina, Puppis, and Vela so that (except for omicron) each Greek letter is found in only one of the three. However, ο (omicron) is now commonly used for two stars, one each in Vela and Puppis. In the Coelum Australe Stelliferum itself, ο Velorum is labelled ο (omicron) Argus (du Navire in the French edition), while ο Puppis is labelled (Latin) o Argus in puppi (Pouppe du Navire in the French edition). Some later authors state the reverse, that Lacaille actually assigned omicron to ο Puppis and Latin lower case 'o' to ο Velorum. Modern catalogs and atlases generally use omicron for both stars.
References
{{reflist|refs=
{{cite Gaia DR3|5318547273548061824}}
| last1=Gontcharov | first1=G. A.
| title=Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system
| journal=Astronomy Letters
| volume=32| issue=11| pages=759–771| date=November 2006
| doi=10.1134/S1063773706110065 | bibcode=2006AstL...32..759G
| arxiv=1606.08053 | s2cid=119231169
| postscript=. }}
| title=XHIP: An extended hipparcos compilation
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}
}}
{{Stars of Vela}}
{{DEFAULTSORT:Omicron Velorum}}
Category:B-type main-sequence stars