Universe Guide


Beid, Omicron1 Eridani, 38 Eridani, HD26574, HIP19587, HR1298

Beid (Omicron1 Eridani) is a blue to white pulsating giant star that can be located in the constellation of Eridanus. Beid is the brightest star in Eridanus 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.

Omicron1 Eridani is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR1298. HIP19587 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD26574. The Id of the star in the Gould Star Catalogue is 185. 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.

Beid has alternative name(s), 38 Eridani, Omicron1 Eridani , omi01 Eri.

Location of Beid

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 Beid, the location is 04h 11m 51.93 and -06d50`16.0 .

Proper Motion of Beid

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 81.92 ± 0.20 miliarcseconds/year towards the north and 10.76 ± 0.32 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Beid

Beid has a spectral type of F2II-III. This means the star is a blue to white giant star. The star is 7428.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24227.4131923200000000s. The star has a B-V Colour Index of 0.32 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,116 Kelvin.

Beid Radius has been calculated as being 3.68 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,563,923.45.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.57. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is 0.21 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Beid Apparent and Absolute Magnitudes

Beid has an apparent magnitude of 4.04 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 1.11 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.18. 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 Beid

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 25.98 which gave the calculated distance to Beid as 125.54 light years away from Earth or 38.49 parsecs. It would take a spaceship travelling at the speed of light, 125.54 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 26.80 which put Beid at a distance of 121.70 light years or 37.31 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 7,428.00 Parsecs or 24,227.41 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 Beid

The star is a pulsating Delta Scuti 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. Beid brightness ranges from a magnitude of 4.148 to a magnitude of 4.114 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Beid Facts

Alternative Names

Traditional/Proper NameBeid
Short Nameomi01 Eri
Bayer DesignationOmicron1 Eridani
Alternative Name(s)38 Eridani, Omicron1 Eridani
Hipparcos Library I.D.19587
Yale Bright Star Catalogue (HR) Id1298
Bonner DurchmusterungBD-07 764
Gould I.D.185
Henry Draper Designation26574

Visual Facts

Star Typegiant star
Absolute Magnitude1.11 / 1.18
Visual / Apparent Magnitude4.04
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)04h 11m 51.93
Declination (Dec.)-06d50`16.0
Galactic Latitude-38.39 degrees
Galactic Longitude199.32 degrees
1997 Distance from Earth25.98 Parallax (milliarcseconds)
 125.54 Light Years
 38.49 Parsecs
2007 Revised Distance from Earth26.80 Parallax (milliarcseconds)
 121.70 Light Years
 37.31 Parsecs
Galacto-Centric Distance24,227.41 Light Years / 7,428.00 Parsecs
Proper Motion Dec.81.92 ± 0.20 milliarcseconds/year
Proper Motion RA.10.76 ± 0.32 milliarcseconds/year
B-V Index0.32
Radial Velocity11.00 ± 4.10 km/s
Iron Abundance0.21 ± 9.99 Fe/H
Spectral TypeF2II-III
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti
Mean Variability Period in Days0.021
Variable Magnitude Range (Brighter - Dimmer)4.114 - 4.148

Estimated Facts

Calculated Effective Temperature7,116 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Beid in Eridanus

Beid (Omicron1 Eridani) Location in Eridanus

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

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