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Omicron Velorum, HD74195, HIP42536, HR3447

Omicron Velorum is a blue pulsating subgiant star that can be located in the constellation of Vela. The description is based on the spectral class. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Omicron Velorum's Alternative Names

Omicron Velorum (Omi Vel) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR3447. HIP42536 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD74195.

Omicron Velorum has alternative name(s) :- , omi Vel.

More details on star alternative names can be found at Star Names .

Location of Omicron Velorum

The location of the star in the night sky is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Omicron Velorum, the location is 08h 40m 17.61 and -52° 55` 19.1 .

Proper Motion of Omicron Velorum

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving 34.44 ± 0.31 miliarcseconds/year towards the north and -24.42 ± 0.35 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 16.10000 km/s with an error of about 0.70 km/s .

Omicron Velorum Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 2,548.84 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature) of Omicron Velorum

Omicron Velorum has a spectral type of B3IV. This means the star is a blue subgiant star. The star is 7,401.00 Parsecs from the Galactic Centre or terms of Light Years is 24,139.35 s. The star has a B-V Colour Index of -0.16 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 14,202 Kelvin.

Omicron Velorum Radius has been calculated as being 4.47 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,109,649.87.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 4.45. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Omicron Velorum Apparent and Absolute Magnitudes

Omicron Velorum has an apparent magnitude of 3.60 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of -2.31 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.30. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to Omicron Velorum

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.59 which gave the calculated distance to Omicron Velorum as 494.94 light years away from Earth or 151.75 parsecs. It would take a spaceship travelling at the speed of light, 494.94 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 6.61 which put Omicron Velorum at a distance of 493.44 light years or 151.29 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

The star's Galacto-Centric Distance is 7,401.00 Parsecs or 24,139.35 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of Omicron Velorum

The star is a pulsating Beta Cephei variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. Omicron Velorum brightness ranges from a magnitude of 3.552 to a magnitude of 3.518 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 2.8 days (variability).

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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Omicron Velorum Facts

Visual Facts

 Omicron Velorum
Alternative NamesOmi Vel, HD 74195, HIP 42536, HR 3447, omi Vel
Spectral TypeB3IV
Multiple Star SystemNo / Unknown
Star TypeSubgiant Star
Colour blue
GalaxyMilky Way
Absolute Magnitude-2.31 / -2.30
Visual / Apparent Magnitude3.60
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)08h 40m 17.61
Declination (Dec.)-52° 55` 19.1
Galactic Latitude-6.80 degrees
Galactic Longitude270.25 degrees
1997 Distance from Earth6.59 Parallax (milliarcseconds)
 494.94 Light Years
 151.75 Parsecs
2007 Distance from Earth6.61 Parallax (milliarcseconds)
 493.44 Light Years
 151.29 Parsecs
Galacto-Centric Distance24,139.35 Light Years / 7,401.00 Parsecs
Proper Motion Dec.34.44 ± 0.31 milliarcseconds/year
Proper Motion RA.-24.42 ± 0.35 milliarcseconds/year
B-V Index-0.16
Radial Velocity16.10 ± 0.70 km/s
Semi-Major Axis7351.00
Stellar Luminosity (Lsun)2,548.84

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeBeta Cephei
Mean Variability Period in Days2.798
Variable Magnitude Range (Brighter - Dimmer)3.518 - 3.552

Estimated Facts

Calculated Effective Temperature14,202 Kelvin

Sources and Links

SIMBAD SourceLink

Location of Omicron Velorum in Vela

Omicron Velorum (Omicron Velorum) Location in Vela

The map was generated using Night Vision, an awesome free application by Brian Simpson.

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