Universe Guide

BB Eridani

BB Eridani Facts

  • BB Eridani is a pulsating variable star that can be located in the constellation of Eridanus. The description is based on the spectral class.
  • BB Eridani is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (F4) of the star, the star's colour is yellow to white .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 749.80 light years away from us. Distance

BB Eridani's Alternative Names

HIP22750 is the reference name for the star in the Hipparcos Star Catalogue.

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

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

Location of BB 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 BB Eridani, the location is 04h 53m 37.50 and -19° 26` 01.1 .

Radial Velocity and Proper Motion of BB 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 0.03 ± 1.43 milliarcseconds/year towards the north and 32.91 ± 2.80 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 245.00000 km/s with an error of about 2.60 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 BB Eridani

BB Eridani Colour and Temperature

Based on the star's spectral type of F4 , BB Eridani's colour and type is yellow to white variable star. Based on the star's spectral, the stars temperature is between 6,000.00 and 7,500.00 degrees kelvin.

BB Eridani Iron Abundance

BB Eridani Iron Abundance is -1.36 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.

BB Eridani Apparent and Absolute Magnitudes

BB Eridani has an apparent magnitude of 11.71 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 3.83 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.90. 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 BB Eridani

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.66000 which gave the calculated distance to BB Eridani as 1226.18 light years away from Earth or 375.94 parsecs. If you want that in miles, it is about 7,208,252,860,090,278.91, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 4.35000 which put BB Eridani at a distance of 749.80 light years or 229.89 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.

Using the 2007 distance, the star is roughly 47,417,885.90 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

Travel Time to BB 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 A380736683,190,690.79
Speed of Sound (Mach 1)767.269655,348,187.43
Concorde (Mach 2)1,534.54327,673,666.65
New Horizons Probe33,00015,237,222.68
Speed of Light670,616,629.00749.80

Variable Type of BB Eridani

The star is a pulsating RR Lyrae type with a 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. BB Eridani brightness ranges from a magnitude of 12.008 to a magnitude of 11.049 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.6 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 BB Eridani Facts and Figures

Visual Facts

Primary / Proper / Traditional NameBB Eridani
Alternative NamesBB Eri, HIP 22750, BB Eri
Spectral TypeF4
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
ColourYellow - White
GalaxyMilky Way
Absolute Magnitude 3.83 / 4.90
Visual / Apparent Magnitude11.71
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)04h 53m 37.50
Declination (Dec.)-19° 26` 01.1
Galactic Latitude-34.36057177 degrees
Galactic Longitude218.81918225 degrees
1997 Distance from Earth2.66000 Parallax (milliarcseconds)
 1226.18 Light Years
 375.94 Parsecs
2007 Distance from Earth4.35000 Parallax (milliarcseconds)
 749.80 Light Years
 229.89 Parsecs
 47,417,885.90 Astronomical Units
Proper Motion Dec.0.03000 ± 1.43000 milliarcseconds/year
Proper Motion RA.32.91000 ± 2.80000 milliarcseconds/year
B-V Index-99
Radial Velocity245.00000 ± 2.60 km/s
Iron Abundance-1.3600 ± 9.99 Fe/H

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeRR Lyrae type with a
Mean Variability Period in Days0.570
Variable Magnitude Range (Brighter - Dimmer)11.049 - 12.008

Estimated Calculated Facts

Calculated Temperature Range6,000.00 - 7,500.00

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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