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56 Eridani, HD30076, HIP22024, HR1508

56 Eridani is a blue eruptive main sequence dwarf star that can be located in the constellation of Eridanus. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

56 Eridani's Alternative Names

The Id of the star in the Yale Bright Star Catalogue is HR1508. HIP22024 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD30076.

56 Eridani has alternative name(s) :- , DX Eri.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 56 Eridani with it shortened to 56 Eri.

The Gould star designation is one that was designed by American astronomer, Benjamin Apthorp Gould. Gould stars are predominantly in the Southern and Equatorial constellations but do appear in northern constellations such as Bootes and Orion. The star has the designation 263 G. Eridani. There are no stars with a Gould designation in Ursa Major for example.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD-08 929.

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

Location of 56 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 56 Eridani, the location is 04h 44m 05.32 and -08° 30` 12.9 .

Proper Motion of 56 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 2.72 ± 0.47 miliarcseconds/year towards the north and 4.92 ± 0.67 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 15.10000 km/s with an error of about 2.90 km/s .

Physical Properties (Colour, Temperature) of 56 Eridani

56 Eridani has a spectral type of B2Ve. This means the star is a blue main sequence dwarf star. The star has a B-V Colour Index of -0.07 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 10,845 Kelvin.

56 Eridani Radius has been calculated as being 7.59 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 5,283,858.75.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 27.57. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

56 Eridani Apparent and Absolute Magnitudes

56 Eridani has an apparent magnitude of 5.78 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 -2.29 If you used the 2007 Parallax value, you would get an absolute magnitude of -5.09. 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 56 Eridani

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.43 which gave the calculated distance to 56 Eridani as 1342.24 light years away from Earth or 411.52 parsecs. It would take a spaceship travelling at the speed of light, 1342.24 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 0.67 which put 56 Eridani at a distance of 4868.11 light years or 1492.54 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 56 Eridani

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. 56 Eridani brightness ranges from a magnitude of 5.823 to a magnitude of 5.718 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.

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56 Eridani Facts

Visual Facts

Alternative NamesHD 30076, HIP 22024, HR 1508, 263 G. Eridani, 56 Eri, BD-08 929, DX Eri
Star Type main sequence Dwarf Star
GalaxyMilky Way
Absolute Magnitude-2.29 / -5.09
Visual / Apparent Magnitude5.78
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)04h 44m 05.32
Declination (Dec.)-08° 30` 12.9
Galactic Latitude-32.12 degrees
Galactic Longitude205.72 degrees
1997 Distance from Earth2.43 Parallax (milliarcseconds)
 1342.24 Light Years
 411.52 Parsecs
2007 Revised Distance from Earth0.67 Parallax (milliarcseconds)
 4868.11 Light Years
 1492.54 Parsecs
Proper Motion Dec.2.72 ± 0.47 milliarcseconds/year
Proper Motion RA.4.92 ± 0.67 milliarcseconds/year
B-V Index-0.07
Radial Velocity15.10 ± 2.90 km/s
Spectral TypeB2Ve
Colour(B) blue

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeGamma Cassiopeiae
Mean Variability Period in Days0.096
Variable Magnitude Range (Brighter - Dimmer)5.718 - 5.823

Estimated Facts

Calculated Effective Temperature10,845 Kelvin

Sources and Links

SIMBAD SourceLink

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