Universe Guide


22 Andromedae, HD571, HIP841

22 Andromedae is a blue to white luminous giant star that can be located in the constellation of Andromeda. 22 Andromedae is the brightest star in Andromeda based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP841 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD571.

Location of 22 Andromedae

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 22 Andromedae, the location is 00h 10m 19.24 and +46d04`20.2 .

Proper Motion of 22 Andromedae

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 0.28 ± 0.14 miliarcseconds/year towards the north and 5.49 ± 0.28 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 22 Andromedae

22 Andromedae has a spectral type of F2II. This means the star is a blue to white luminous giant star. The star is 7562.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24664.4720732800000000s. The star has a B-V Colour Index of 0.4 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,398 Kelvin.

22 Andromedae Radius has been calculated as being 23.38 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 16,267,593.57.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 28.50. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

22 Andromedae Apparent and Absolute Magnitudes

22 Andromedae has an apparent magnitude of 5.01 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 -2.44 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.87. 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 22 Andromedae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.24 which gave the calculated distance to 22 Andromedae as 1006.68 light years away from Earth or 308.64 parsecs. It would take a spaceship travelling at the speed of light, 1006.68 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 2.65 which put 22 Andromedae at a distance of 1230.81 light years or 377.36 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 7,562.00 Parsecs or 24,664.47 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.

22 Andromedae Facts

Alternative Names

Traditional/Proper Name22 Andromedae
Flamsteed Name22 Andromedae
Flamsteed Short Name22 And
Hipparcos Library I.D.841
Bonner DurchmusterungBD+45 17
Henry Draper Designation571

Visual Facts

Star Typeluminous giant star
Absolute Magnitude-2.44 / -2.87
Visual / Apparent Magnitude5.01
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)00h 10m 19.24
Declination (Dec.)+46d04`20.2
Galactic Latitude-16.21 degrees
Galactic Longitude115.52 degrees
1997 Distance from Earth3.24 Parallax (milliarcseconds)
 1006.68 Light Years
 308.64 Parsecs
2007 Revised Distance from Earth2.65 Parallax (milliarcseconds)
 1230.81 Light Years
 377.36 Parsecs
Galacto-Centric Distance24,664.47 Light Years / 7,562.00 Parsecs
Proper Motion Dec.0.28 ± 0.14 milliarcseconds/year
Proper Motion RA.5.49 ± 0.28 milliarcseconds/year
B-V Index0.40
Radial Velocity-8.20 ± 2.20 km/s
Spectral TypeF2II
Colour(F) blue to white

Estimated Facts

Calculated Effective Temperature6,398 Kelvin

Sources and Links

SIMBAD SourceLink

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