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7 Pegasi, HD206487, HIP107151, HR8289

7 Pegasi is a red giant star that can be located in the constellation of Pegasus. The description is based on the spectral class. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

7 Pegasi's Alternative Names

The Id of the star in the Yale Bright Star Catalogue is HR8289. HIP107151 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD206487.

7 Pegasi has alternative name(s) :- , NSV 13848.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 7 Pegasi with it shortened to 7 Peg.

The Gould star designation is one that was designed by American astronomer, Benjamin Apthorp Gould. Gould stars are predominantly in the Southern and Equatorial constellations but do appear in northern constellations such as Bootes and Orion. The star has the designation 9 G. Pegasi. There are no stars with a Gould designation in Ursa Major for example.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+05 4850.

More details on star alternative names can be found at Star Names .

Location of 7 Pegasi

The location of the star in the night sky 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 7 Pegasi, the location is 21h 42m 15.44 and +05° 40` 48.5 .

Proper Motion of 7 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 -5.20 ± 0.22 miliarcseconds/year towards the north and 10.80 ± 0.34 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is -12.01000 km/s with an error of about 0.41 km/s .

Physical Properties (Colour, Temperature) of 7 Pegasi

7 Pegasi has a spectral type of M2III. This means the star is a red giant star. The star is 7,314.00 Parsecs from the Galactic Centre or terms of Light Years is 23,855.59 s. The star has a B-V Colour Index of 1.65 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,640 Kelvin.

7 Pegasi Radius has been calculated as being 32.71 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 22,761,041.55.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 45.78. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

7 Pegasi Apparent and Absolute Magnitudes

7 Pegasi has an apparent magnitude of 5.30 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 -0.72 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.45. 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 7 Pegasi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.25 which gave the calculated distance to 7 Pegasi as 521.86 light years away from Earth or 160 parsecs. It would take a spaceship travelling at the speed of light, 521.86 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 4.47 which put 7 Pegasi at a distance of 729.67 light years or 223.71 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 7,314.00 Parsecs or 23,855.59 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*. 7 Pegasi brightness ranges from a magnitude of 5.410 to a magnitude of 5.368 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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7 Pegasi Facts

Visual Facts


Primary / Proper / Traditional Name7 Pegasi
Alternative NamesHD 206487, HIP 107151, HR 8289, 9 G. Pegasi, 7 Peg, BD+05 4850, NSV 13848
Spectral TypeM2III
Multiple Star SystemNo / Unknown
Star TypeGiant Star
Colour red
GalaxyMilky Way
ConstellationPegasus
Absolute Magnitude-0.72 / -1.45
Visual / Apparent Magnitude5.30
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)21h 42m 15.44
Declination (Dec.)+05° 40` 48.5
Galactic Latitude-33.75 degrees
Galactic Longitude61.36 degrees
1997 Distance from Earth6.25 Parallax (milliarcseconds)
 521.86 Light Years
 160 Parsecs
2007 Distance from Earth4.47 Parallax (milliarcseconds)
 729.67 Light Years
 223.71 Parsecs
Galacto-Centric Distance23,855.59 Light Years / 7,314.00 Parsecs
Proper Motion Dec.-5.20 ± 0.22 milliarcseconds/year
Proper Motion RA.10.80 ± 0.34 milliarcseconds/year
B-V Index1.65
Radial Velocity-12.01 ± 0.41 km/s
Eccentricity0.01
Semi-Major Axis7309.00

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Mean Variability Period in Days0.033
Variable Magnitude Range (Brighter - Dimmer)5.368 - 5.410

Estimated Facts


Calculated Effective Temperature3,640 Kelvin

Sources and Links


SIMBAD SourceLink

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