Universe Guide

BC Eridani

BC Eridani Facts

  • BC Eridani is a eclipsing variable star that can be located in the constellation of Eridanus. The description is based on the spectral class.
  • BC Eridani is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (A6) of the star, the star's colour is blue - white .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • The star is calculated at being about 1399.84 light years away from us. Distance

BC Eridani's Alternative Names

HIP22234 is the reference name for the star in the Hipparcos Star Catalogue.

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

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

Location of BC Eridani

The location of the variable 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 object is compared to the celestial equator and is expressed in degrees. For BC Eridani, the location is 04h 46m 59.00 and -14° 37` 23.3 .

Radial Velocity and Proper Motion of BC Eridani

Proper Motion

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 -6.44 ± 1.01 milliarcseconds/year towards the north and 16.68 ± 1.91 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 65.00000 km/s with an error of about 7.40 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties of BC Eridani

BC Eridani Temperature and Colour

Based on the star's spectral type of A6 , BC Eridani's colour and type is blue - white variable star. The star has a B-V Colour Index of 0.49 which means the star's temperature is about 6,140 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

BC Eridani Radius

BC Eridani estimated radius has been calculated as being 2.33 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,618,169.79.km. If you need the diameter of the star, you just need to multiple the radius by 2. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

BC Eridani Iron Abundance

BC Eridani Iron Abundance is -1.12 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context. The value comes from the Hipparcos Extended Catalog.

BC Eridani Apparent and Absolute Magnitudes

BC Eridani has an apparent magnitude of 10.91 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. Using the supplied Parallax value, you would get an absolute magnitude of 2.75 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 BC Eridani

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.33000 which gave the calculated distance to BC Eridani as 1399.84 light years away from Earth or 429.18 parsecs. If you want that in miles, it is about 8,229,134,942,397,344.62, based on 1 Ly = 5,878,625,373,183.61 miles.

Travel Time to BC Eridani

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A3807361,275,483,671.11
Speed of Sound (Mach 1)767.2691,223,503,076.42
Concorde (Mach 2)1,534.54611,750,740.90
New Horizons Probe33,00028,447,150.97
Speed of Light670,616,629.001,399.84

Variable Type of BC Eridani

The star is a eclipsing W Ursae Majoris/Cont 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. BC Eridani brightness ranges from a magnitude of 11.500 to a magnitude of 10.895 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.5 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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Additional BC Eridani Facts and Figures

Visual Facts

Primary / Proper / Traditional NameBC Eridani
Alternative NamesBC Eri, HIP 22234, BC Eri
Spectral TypeA6
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
GalaxyMilky Way
Absolute Magnitude 2.75
Visual / Apparent Magnitude10.91
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)04h 46m 59.00
Declination (Dec.)-14° 37` 23.3
Galactic Latitude-34.06344605 degrees
Galactic Longitude212.70333546 degrees
Distance from Earth2.33000 Parallax (milliarcseconds)
 1399.84 Light Years
 429.18 Parsecs
 88,524,112.70 Astronomical Units
Proper Motion Dec.-6.44000 ± 1.01000 milliarcseconds/year
Proper Motion RA.16.68000 ± 1.91000 milliarcseconds/year
B-V Index0.49
Radial Velocity65.00000 ± 7.40 km/s
Iron Abundance-1.1200 ± 9.99 Fe/H

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count None/Unaware

Variable Star Details

Variable Star ClassEclipsing
Variable Star TypeW Ursae Majoris/Cont
Mean Variability Period in Days0.527
Variable Magnitude Range (Brighter - Dimmer)10.895 - 11.500

Estimated Calculated Facts

Radius (x the Sun)2.33
Effective Temperature6,140 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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