Universe Guide


BS Indi, HD202947, HIP105404

BS Indi is a orange to red eclipsing binary system main sequence dwarf star that can be located in the constellation of Indus. BS Indi is the brightest star in Indus based on the Hipparcos 2007 apparent magnitude. The star can not be seen by the naked eye, you need a telescope to see it.

HIP105404 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD202947.

BS Indi has alternative name(s), BS Ind.

Location of BS Indi

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 BS Indi, the location is 21h 20m 59.78 and -52d28`39.2 .

Proper Motion of BS Indi

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 -103.88 ± 0.90 miliarcseconds/year towards the north and 25.45 ± 1.40 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of BS Indi

BS Indi has a spectral type of K0V. This means the star is a orange to red main sequence dwarf star. The star is 7369.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24034.9768193600000000s. The star has a B-V Colour Index of 0.85 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,164 Kelvin.

BS Indi Radius has been calculated as being 0.90 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 624,253.06.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 0.88. 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 -0.72 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

BS Indi Apparent and Absolute Magnitudes

BS Indi has an apparent magnitude of 8.89 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 5.57 If you used the 2007 Parallax value, you would get an absolute magnitude of 5.62. 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 BS Indi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 21.72 which gave the calculated distance to BS Indi as 150.17 light years away from Earth or 46.04 parsecs. It would take a spaceship travelling at the speed of light, 150.17 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 22.15 which put BS Indi at a distance of 147.25 light years or 45.15 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 7,369.00 Parsecs or 24,034.98 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 BS Indi

The star is a eclipsing binary system Beta Lyrae (Sheliak) 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. BS Indi brightness ranges from a magnitude of 9.315 to a magnitude of 9.010 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.4 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.

BS Indi Facts

Alternative Names

Traditional/Proper NameBS Indi
Short NameBS Ind
Hipparcos Library I.D.105404
Henry Draper Designation202947

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude5.57 / 5.62
Visual / Apparent Magnitude8.89
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)21h 20m 59.78
Declination (Dec.)-52d28`39.2
Galactic Latitude-43.69 degrees
Galactic Longitude344.94 degrees
1997 Distance from Earth21.72 Parallax (milliarcseconds)
 150.17 Light Years
 46.04 Parsecs
2007 Revised Distance from Earth22.15 Parallax (milliarcseconds)
 147.25 Light Years
 45.15 Parsecs
Galacto-Centric Distance24,034.98 Light Years / 7,369.00 Parsecs
Proper Motion Dec.-103.88 ± 0.90 milliarcseconds/year
Proper Motion RA.25.45 ± 1.40 milliarcseconds/year
B-V Index0.85
Radial Velocity19.50 ± 7.70 km/s
Iron Abundance-0.72 ± 9.99 Fe/H
Spectral TypeK0V
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeBeta Lyrae (Sheliak)
Mean Variability Period in Days0.435
Variable Magnitude Range (Brighter - Dimmer)9.010 - 9.315

Estimated Facts

Calculated Effective Temperature5,164 Kelvin

Sources and Links

SIMBAD SourceLink

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