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75 Pegasi - HD222133 - HIP116611

75 Pegasi is a blue eclipsing binary system main sequence dwarf star that can be located in the constellation of Pegasus. HIP116611 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD222133. 75 Pegasi has alternative name(s), 75 Pegasi , KS_Peg, 75 Peg.

Location of 75 Pegasi

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 75 Pegasi, the location is 23h 37m 56.77 and +18d24`02.2 .

Proper Motion of 75 Pegasi

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 017.37 ± 000.15 towards the north and 048.85 ± 000.27 east if we saw them in the horizon.

75 Pegasi Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 20.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of 75 Pegasi

75 Pegasi has a spectral type of A1Vn. This means the star is a blue main sequence dwarf star. The star has a B-V Colour Index of 0.01 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,392 Kelvin.

75 Pegasi has been calculated as 2.06 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,431,726.87.km.

75 Pegasi Apparent and Absolute Magnitudes

75 Pegasi has an apparent magnitude of 5.49 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 1.17 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.22. 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 75 Pegasi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 13.65 which gave the calculated distance to 75 Pegasi as 238.95 light years away from Earth or 73.26 parsecs. It would take a spaceship travelling at the speed of light, 238.95 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 14.01 which put 75 Pegasi at a distance of 232.81 light years or 71.38 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 75 Pegasi

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. 75 Pegasi brightness ranges from a magnitude of 6.000 to a magnitude of 5.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.0 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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

75 Pegasi Facts

Alternative Names

Traditional Name75 Pegasi
Short NameKS Peg, 75 Peg
Alternative Name(s)75 Pegasi
Hipparcos Library I.D.116611
Bonner DurchmusterungBD+17 4952
Henry Draper Designation222133

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude1.17 / 1.22
Apparent Magnitude5.49
Right Ascension (R.A.)23h 37m 56.77
Declination (Dec.)+18d24`02.2
1997 Distance from Earth13.65 Parallax (milliarcseconds)
 238.95 Light Years
 73.26 Parsecs
2007 Revised Distance from Earth14.01 Parallax (milliarcseconds)
 232.81 Light Years
 71.38 Parsecs
Proper Motion Dec.17.37 ± 0.15 milliarcseconds/year
Proper Motion RA.48.85 ± 0.27 milliarcseconds/year
B-V Index0.01
Spectral TypeA1Vn
Colour(A) blue

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeBeta Lyrae (Sheliak)
Mean Variability Period in Days1.000
Variable Magnitude Range (Brighter - Dimmer)5.000 - 6.000

Estimated Facts

Radius (x the Sun)2.06
Luminosity (x the Sun)20.0000000
Calculated Effective Temperature9,392 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
222133+17 4952.0A5.4000052.0000017.00000A0White
B11.600001958

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