Universe Guide


DZ Eridani - HD28843 - HIP21192

DZ Eridani is a blue rotating giant star that can be located in the constellation of Eridanus. HIP21192 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD28843. The Id of the star in the Gould Star Catalogue is 234. 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. DZ Eridani has alternative name(s), DZ_Eri.

Location of DZ Eridani

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 DZ Eridani, the location is 04h 32m 37.54 and -03d12`34.2 .

Proper Motion of DZ Eridani

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 -017.16 ± 000.19 towards the north and 017.78 ± 000.35 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of DZ Eridani

DZ Eridani has a spectral type of B9III. This means the star is a blue giant star. The star has a B-V Colour Index of -0.11 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 12,006 Kelvin.

DZ Eridani has been calculated as 2.00 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,388,639.40.km.

DZ Eridani Apparent and Absolute Magnitudes

DZ Eridani has an apparent magnitude of 5.76 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 0.17 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.06. 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 DZ Eridani

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.61 which gave the calculated distance to DZ Eridani as 428.60 light years away from Earth or 131.41 parsecs. It would take a spaceship travelling at the speed of light, 428.60 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 6.86 which put DZ Eridani at a distance of 475.46 light years or 145.77 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.

Variable Type of DZ Eridani

The star is a rotating SX Arietis 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. DZ Eridani brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.0 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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

DZ Eridani Facts

Alternative Names

Traditional NameDZ Eridani
Short NameDZ Eri
Hipparcos Library I.D.21192
Bonner DurchmusterungBD-03 809
Gould I.D.234
Henry Draper Designation28843

Visual Facts

Star Typegiant star
Absolute Magnitude0.17 / -0.06
Apparent Magnitude5.76
Right Ascension (R.A.)04h 32m 37.54
Declination (Dec.)-03d12`34.2
1997 Distance from Earth7.61 Parallax (milliarcseconds)
 428.60 Light Years
 131.41 Parsecs
2007 Revised Distance from Earth6.86 Parallax (milliarcseconds)
 475.46 Light Years
 145.77 Parsecs
Proper Motion Dec.-17.16 ± 0.19 milliarcseconds/year
Proper Motion RA.17.78 ± 0.35 milliarcseconds/year
B-V Index-0.11
Spectral TypeB9III
Colour(B) blue

Variable Star Details

Variable Star ClassRotating
Variable Star TypeSX Arietis
Mean Variability Period in Days1.000

Estimated Facts

Radius (x the Sun)2.00
Calculated Effective Temperature12,006 Kelvin

Sources and Links

SIMBAD SourceLink

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