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HD 220773, HIP115697

HD 220773 is a white to yellow star that can be located in the constellation of Pegasus. The star can not be seen by the naked eye, you need a telescope to see it. The star has an estimated age of 5.70 Billion of Years but could be as young as 5.20 to 6.40 according to Hipparcos.

HIP115697 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD220773.

Location of HD 220773

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 HD 220773, the location is 23h 26m 27.43 and +08d 38` 39.8 .

Proper Motion of HD 220773

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 -222.87 ± 0.48 miliarcseconds/year towards the north and 26.90 ± 0.65 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 -37.70000 km/s with an error of about 0.30 km/s .

Physical Properties (Colour, Temperature, Metallicity, Age, Mass, Radius) of HD 220773

HD 220773 has a spectral type of G0. This means the star is a white to yellow star. The star is 7400.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24136.0874560000000000s. The star has a B-V Colour Index of 0.6 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,875 Kelvin.

HD 220773 Radius has been calculated as being 1.66 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,157,007.19.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.74. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 1.16 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is 0.090000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

The stars age according to Hipparcos data files put the star at an age of about 5.70 Billion years old but could be between 5.20 and 6.40 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

HD 220773 Apparent and Absolute Magnitudes

HD 220773 has an apparent magnitude of 7.10 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 3.67 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.57. 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 HD 220773

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 20.65 which gave the calculated distance to HD 220773 as 157.95 light years away from Earth or 48.43 parsecs. It would take a spaceship travelling at the speed of light, 157.95 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 19.65 which put HD 220773 at a distance of 165.99 light years or 50.89 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 7,400.00 Parsecs or 24,136.09 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

HD 220773 Facts

Alternative Names

Traditional/Proper NameHD 220773
Hipparcos Library I.D.115697
Bonner DurchmusterungBD+07 5030
Henry Draper Designation220773

Visual Facts

Star Type star
Age5.70 Billion Years Old
Age Range5.20 - 6.40 Billion Years Old
Absolute Magnitude3.67 / 3.57
Visual / Apparent Magnitude7.10
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)23h 26m 27.43
Declination (Dec.)+08d 38` 39.8
Galactic Latitude-48.72 degrees
Galactic Longitude90.04 degrees
1997 Distance from Earth20.65 Parallax (milliarcseconds)
 157.95 Light Years
 48.43 Parsecs
2007 Revised Distance from Earth19.65 Parallax (milliarcseconds)
 165.99 Light Years
 50.89 Parsecs
Galacto-Centric Distance24,136.09 Light Years / 7,400.00 Parsecs
Proper Motion Dec.-222.87 ± 0.48 milliarcseconds/year
Proper Motion RA.26.90 ± 0.65 milliarcseconds/year
B-V Index0.60
Radial Velocity-37.70 ± 0.30 km/s
Iron Abundance0.10 ± 0.08 Fe/H
Spectral TypeG0
Colour(G) White to Yellow

Estimated Facts

Calculated Effective Temperature5,875 Kelvin
Mass Compared to the Sun1.16

Sources and Links

SIMBAD SourceLink

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