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84 Herculis - HD161239 - HIP86731

84 Herculis is a white to yellow giant star that can be located in the constellation of Hercules. HIP86731 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD161239. 84 Herculis has alternative name(s), 84 Herculis , 84 Her.

Location of 84 Herculis

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 84 Herculis, the location is 17h 43m 21.64 and +24d19`39.5 .

Proper Motion of 84 Herculis

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 072.93 ± 000.24 towards the north and -116.57 ± 000.33 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 84 Herculis

84 Herculis has a spectral type of G2IIIb. This means the star is a white to yellow giant star. The star has a B-V Colour Index of 0.68 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,625 Kelvin.

84 Herculis has been calculated as 2.68 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,866,874.36.km.

84 Herculis Apparent and Absolute Magnitudes

84 Herculis has an apparent magnitude of 5.73 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 2.82 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.77. 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 84 Herculis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 26.13 which gave the calculated distance to 84 Herculis as 124.82 light years away from Earth or 38.27 parsecs. It would take a spaceship travelling at the speed of light, 124.82 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 25.60 which put 84 Herculis at a distance of 127.41 light years or 39.06 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.

84 Herculis Facts

Alternative Names

Traditional Name84 Herculis
Short Name84 Her
Alternative Name(s)84 Herculis
Hipparcos Library I.D.86731
Bonner DurchmusterungBD+24 3237
Henry Draper Designation161239

Visual Facts

Star Typegiant star
Absolute Magnitude2.82 / 2.77
Apparent Magnitude5.73
Right Ascension (R.A.)17h 43m 21.64
Declination (Dec.)+24d19`39.5
1997 Distance from Earth26.13 Parallax (milliarcseconds)
 124.82 Light Years
 38.27 Parsecs
2007 Revised Distance from Earth25.60 Parallax (milliarcseconds)
 127.41 Light Years
 39.06 Parsecs
Proper Motion Dec.72.93 ± 0.24 milliarcseconds/year
Proper Motion RA.-116.57 ± 0.33 milliarcseconds/year
B-V Index0.68
Spectral TypeG2IIIb
Colour(G) White to Yellow

Estimated Facts

Radius (x the Sun)2.68
Calculated Effective Temperature5,625 Kelvin

Sources and Links

SIMBAD SourceLink

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