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Groombridge 1830, HD103095, HIP57939

Groombridge 1830 is a white to yellow star that can be located in the constellation of UrsaMajor. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP57939 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD103095. The Gliese ID of the star is GL 451A. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Ref : Star Names.

Groombridge 1830 has alternative name(s), NSV 05374.

Location of Groombridge 1830

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 Groombridge 1830, the location is 11h 52m 55.82 and +37d 43` 58.1 .

Proper Motion of Groombridge 1830

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 -5,813.62 ± 0.22 miliarcseconds/year towards the north and 4,003.98 ± 0.41 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 -98.35000 km/s with an error of about 0.03 km/s .

Groombridge 1830 Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 1.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of Groombridge 1830

Groombridge 1830 has a spectral type of G8Vp. This means the star is a white to yellow star. The star is 7403.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24145.8723563200000000s. The star has a B-V Colour Index of 0.75 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,418 Kelvin.

Groombridge 1830 Radius has been calculated as being 0.50 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 351,273.13.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 0.50. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -1.26 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Groombridge 1830 Apparent and Absolute Magnitudes

Groombridge 1830 has an apparent magnitude of 6.42 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 6.61 If you used the 2007 Parallax value, you would get an absolute magnitude of 6.63. 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 Groombridge 1830

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 109.21 which gave the calculated distance to Groombridge 1830 as 29.87 light years away from Earth or 9.16 parsecs. It would take a spaceship travelling at the speed of light, 29.87 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 109.99 which put Groombridge 1830 at a distance of 29.65 light years or 9.09 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 7,403.00 Parsecs or 24,145.87 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*. Groombridge 1830 brightness ranges from a magnitude of 6.688 to a magnitude of 6.551 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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.

Groombridge 1830 Facts

Alternative Names

Traditional/Proper NameGroombridge 1830
Short NameNSV 05374
Hipparcos Library I.D.57939
Bonner DurchmusterungBD+38 2285
Gliese IDGL 451A
Henry Draper Designation103095

Visual Facts

Star Type star
ConstellationUrsa Major
Absolute Magnitude6.61 / 6.63
Visual / Apparent Magnitude6.42
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)11h 52m 55.82
Declination (Dec.)+37d 43` 58.1
Galactic Latitude73.76 degrees
Galactic Longitude168.51 degrees
1997 Distance from Earth109.21 Parallax (milliarcseconds)
 29.87 Light Years
 9.16 Parsecs
2007 Revised Distance from Earth109.99 Parallax (milliarcseconds)
 29.65 Light Years
 9.09 Parsecs
Galacto-Centric Distance24,145.87 Light Years / 7,403.00 Parsecs
Proper Motion Dec.-5813.62 ± 0.22 milliarcseconds/year
Proper Motion RA.4003.98 ± 0.41 milliarcseconds/year
B-V Index0.75
Radial Velocity-98.35 ± 0.03 km/s
Iron Abundance-1.26 ± 9.99 Fe/H
Spectral TypeG8Vp
Colour(G) White to Yellow

Variable Star Details

Mean Variability Period in Days0.142
Variable Magnitude Range (Brighter - Dimmer)6.551 - 6.688

Estimated Facts

Luminosity (x the Sun)1.0000000
Calculated Effective Temperature5,418 Kelvin

Sources and Links

SIMBAD SourceLink

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