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OY Pegasi - HD210090 - HIP109212

OY Pegasi is a red eruptive star that can be located in the constellation of Pegasus. HIP109212 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD210090. OY Pegasi has alternative name(s), OY_Peg.

Location of OY 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 OY Pegasi, the location is 22h 07m 29.95 and +18d00`02.8 .

Proper Motion of OY 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 -032.58 ± 000.27 towards the north and 024.17 ± 000.38 east if we saw them in the horizon.

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

OY Pegasi has a spectral type of M1. This means the star is a red star. The star has a B-V Colour Index of 1.6 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,775 Kelvin.

OY Pegasi has been calculated as 34.60 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 24,074,858.09.km.

OY Pegasi Apparent and Absolute Magnitudes

OY Pegasi has an apparent magnitude of 6.31 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 -1.00 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.12. 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 OY Pegasi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.45 which gave the calculated distance to OY Pegasi as 945.40 light years away from Earth or 289.86 parsecs. It would take a spaceship travelling at the speed of light, 945.40 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 3.26 which put OY Pegasi at a distance of 1000.50 light years or 306.75 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 OY Pegasi

The star is a eruptive Irregular 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. OY Pegasi brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

OY Pegasi Facts

Alternative Names

Traditional NameOY Pegasi
Short NameOY Peg
Hipparcos Library I.D.109212
Bonner DurchmusterungBD+17 4693
Henry Draper Designation210090

Visual Facts

Star Type star
Absolute Magnitude-1.00 / -1.12
Apparent Magnitude6.31
Right Ascension (R.A.)22h 07m 29.95
Declination (Dec.)+18d00`02.8
1997 Distance from Earth3.45 Parallax (milliarcseconds)
 945.40 Light Years
 289.86 Parsecs
2007 Revised Distance from Earth3.26 Parallax (milliarcseconds)
 1000.50 Light Years
 306.75 Parsecs
Proper Motion Dec.-32.58 ± 0.27 milliarcseconds/year
Proper Motion RA.24.17 ± 0.38 milliarcseconds/year
B-V Index1.60
Spectral TypeM1
Colour(M) Red

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeIrregular

Estimated Facts

Radius (x the Sun)34.60
Calculated Effective Temperature3,775 Kelvin

Sources and Links

SIMBAD SourceLink

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