Universe Guide


39 Pegasi - HD213617 - HIP111278

39 Pegasi is a blue to white main sequence dwarf star that can be located in the constellation of Pegasus. HIP111278 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD213617. 39 Pegasi has alternative name(s), 39 Pegasi , 39 Peg.

Location of 39 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 39 Pegasi, the location is 22h 32m 35.38 and +20d13`47.8 .

Proper Motion of 39 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 030.03 ± 000.29 towards the north and 166.41 ± 000.46 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 39 Pegasi

39 Pegasi has a spectral type of F1V. This means the star is a blue to white main sequence dwarf star. The star has a B-V Colour Index of 0.35 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,967 Kelvin.

39 Pegasi has been calculated as 1.76 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,222,555.61.km.

39 Pegasi Apparent and Absolute Magnitudes

39 Pegasi has an apparent magnitude of 6.43 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 2.81 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.92. 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 39 Pegasi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 18.90 which gave the calculated distance to 39 Pegasi as 172.57 light years away from Earth or 52.91 parsecs. It would take a spaceship travelling at the speed of light, 172.57 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 19.90 which put 39 Pegasi at a distance of 163.90 light years or 50.25 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. 39 Pegasi brightness ranges from a magnitude of 7.000 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.

39 Pegasi Facts

Alternative Names

Traditional Name39 Pegasi
Short Name39 Peg
Alternative Name(s)39 Pegasi
Hipparcos Library I.D.111278
Bonner DurchmusterungBD+19 4949
Henry Draper Designation213617

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude2.81 / 2.92
Apparent Magnitude6.43
Right Ascension (R.A.)22h 32m 35.38
Declination (Dec.)+20d13`47.8
1997 Distance from Earth18.90 Parallax (milliarcseconds)
 172.57 Light Years
 52.91 Parsecs
2007 Revised Distance from Earth19.90 Parallax (milliarcseconds)
 163.90 Light Years
 50.25 Parsecs
Proper Motion Dec.30.03 ± 0.29 milliarcseconds/year
Proper Motion RA.166.41 ± 0.46 milliarcseconds/year
B-V Index0.35
Spectral TypeF1V
Colour(F) blue to white

Variable Star Details

Variable Magnitude Range (Brighter - Dimmer)6.000 - 7.000

Estimated Facts

Radius (x the Sun)1.76
Calculated Effective Temperature6,967 Kelvin

Sources and Links

SIMBAD SourceLink

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