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Delta Centauri, HD105435, HIP59196

Delta Centauri is a blue eruptive subgiant star that can be located in the constellation of Centaurus. Delta Centauri is the brightest star in Centaurus based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Delta Centauri is the Bayer Classification for the star. HIP59196 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD105435. The Id of the star in the Gould Star Catalogue is 94. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major.

Delta Centauri has alternative name(s), Delta CenTau , del Cen.

Location of Delta Centauri

The location of the star in the galaxy 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 Delta Centauri, the location is 12h 08m 21.54 and -50d43`20.7 .

Proper Motion of Delta Centauri

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 -7.19 ± 0.30 miliarcseconds/year towards the north and -49.94 ± 0.47 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Delta Centauri

Delta Centauri has a spectral type of B2IVne. This means the star is a blue subgiant star. The star is 7346.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23959.9592502400000000s. The star has a B-V Colour Index of -0.12 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,367 Kelvin.

Delta Centauri Radius has been calculated as being 7.52 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 5,234,642.06.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 7.88. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Delta Centauri Apparent and Absolute Magnitudes

Delta Centauri has an apparent magnitude of 2.58 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 -2.84 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.94. 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 Delta Centauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 8.25 which gave the calculated distance to Delta Centauri as 395.35 light years away from Earth or 121.21 parsecs. It would take a spaceship travelling at the speed of light, 395.35 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 7.86 which put Delta Centauri at a distance of 414.97 light years or 127.23 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 7,346.00 Parsecs or 23,959.96 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 Delta Centauri

The star is a eruptive Gamma Cassiopeiae 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. Delta Centauri brightness ranges from a magnitude of 2.566 to a magnitude of 2.437 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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.

Delta Centauri Facts

Alternative Names

Short Namedel Cen
Bayer DesignationDelta Centauri
Alternative Name(s)Delta CenTau
Hipparcos Library I.D.59196
Gould I.D.94
Henry Draper Designation105435

Visual Facts

Star Typesubgiant star
Absolute Magnitude-2.84 / -2.94
Visual / Apparent Magnitude2.58
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)12h 08m 21.54
Declination (Dec.)-50d43`20.7
Galactic Latitude11.57 degrees
Galactic Longitude296.00 degrees
1997 Distance from Earth8.25 Parallax (milliarcseconds)
 395.35 Light Years
 121.21 Parsecs
2007 Revised Distance from Earth7.86 Parallax (milliarcseconds)
 414.97 Light Years
 127.23 Parsecs
Galacto-Centric Distance23,959.96 Light Years / 7,346.00 Parsecs
Proper Motion Dec.-7.19 ± 0.30 milliarcseconds/year
Proper Motion RA.-49.94 ± 0.47 milliarcseconds/year
B-V Index-0.12
Radial Velocity11.00 ± 4.00 km/s
Spectral TypeB2IVne
Colour(B) blue

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeGamma Cassiopeiae
Mean Variability Period in Days0.122
Variable Magnitude Range (Brighter - Dimmer)2.437 - 2.566

Estimated Facts

Calculated Effective Temperature12,367 Kelvin

Sources and Links

SIMBAD SourceLink

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