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Upsilon Pegasi - HD220657 - HIP115623

Upsilon Pegasi is a blue to white subgiant star that can be located in the constellation of Pegasus. Upsilon Pegasi is the Bayer Classification for the star. HIP115623 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD220657. Upsilon Pegasi has alternative name(s), 68 Pegasi , 68 Peg.

Location of Upsilon 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 Upsilon Pegasi, the location is 23h 25m 22.66 and +23d24`14.4 .

Proper Motion of Upsilon 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 036.12 ± 000.12 towards the north and 192.19 ± 000.18 east if we saw them in the horizon.

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

Upsilon Pegasi has a spectral type of F8IV. This means the star is a blue to white subgiant star. The star has a B-V Colour Index of 0.61 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,859 Kelvin.

Upsilon Pegasi has been calculated as 6.30 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 4,382,612.55.km.

Upsilon Pegasi Apparent and Absolute Magnitudes

Upsilon Pegasi has an apparent magnitude of 4.42 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 0.79 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.83. 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 Upsilon Pegasi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 18.83 which gave the calculated distance to Upsilon Pegasi as 173.21 light years away from Earth or 53.11 parsecs. It would take a spaceship travelling at the speed of light, 173.21 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 19.14 which put Upsilon Pegasi at a distance of 170.41 light years or 52.25 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.

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.

Upsilon Pegasi Facts

Alternative Names

Short Name68 Peg
Bayer DesignationUpsilon Pegasi
Alternative Name(s)68 Pegasi
Hipparcos Library I.D.115623
Bonner DurchmusterungBD+22 4833
Henry Draper Designation220657

Visual Facts

Star Typesubgiant star
Absolute Magnitude0.79 / 0.83
Apparent Magnitude4.42
Right Ascension (R.A.)23h 25m 22.66
Declination (Dec.)+23d24`14.4
1997 Distance from Earth18.83 Parallax (milliarcseconds)
 173.21 Light Years
 53.11 Parsecs
2007 Revised Distance from Earth19.14 Parallax (milliarcseconds)
 170.41 Light Years
 52.25 Parsecs
Proper Motion Dec.36.12 ± 0.12 milliarcseconds/year
Proper Motion RA.192.19 ± 0.18 milliarcseconds/year
B-V Index0.61
Spectral TypeF8IV
Colour(F) blue to white

Estimated Facts

Radius (x the Sun)6.30
Calculated Effective Temperature5,859 Kelvin

Sources and Links

SIMBAD SourceLink

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