Universe GuideSearchTwitterComments

20 G. Eridani

20 G. Eridani Facts

20 G. Eridani's Alternative Names

HIP12611 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD17006.

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 20 G. Eridani. There are no stars with a Gould designation in Ursa Major for example.

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

Location of 20 G. Eridani

The location of the subgiant 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 object is compared to the celestial equator and is expressed in degrees. For 20 G. Eridani, the location is 02h 42m 08.44 and -46° 31` 27.2 .

Radial Velocity and Proper Motion of 20 G. Eridani

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 -94.41 ± 0.23 miliarcseconds/year towards the north and 9.99 ± 0.31 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 the Sun is 13.00 km/s with an error of about 2.90 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

20 G. Eridani 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 6.86 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature) of 20 G. Eridani

20 G. Eridani has a spectral type of G8IV. This means the star is a white to yellow subgiant star. The star is 7,403.00 Parsecs from the Galactic Centre or in terms of Light Years is 24,145.87 s. The star has a B-V Colour Index of 0.87 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,118 Kelvin.

20 G. Eridani Radius has been calculated as being 2.94 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,047,187.02.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 2.98. 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 0.22 with an error value of 0.06 Fe/H with the Sun has a value of 1 to put it into context.

20 G. Eridani Apparent and Absolute Magnitudes

20 G. Eridani has an apparent magnitude of 6.09 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 3.03 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.00. 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 20 G. Eridani

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 24.47 which gave the calculated distance to 20 G. Eridani as 133.29 light years away from Earth or 40.87 parsecs. It would take a spaceship travelling at the speed of light, 133.29 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 24.07 which put 20 G. Eridani at a distance of 135.51 light years or 41.55 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.

Using the 2007 distance, the star is roughly 8,570,242.98 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

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*.

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.

Hide Explanations
Show GridLines

Additional 20 G. Eridani Facts and Figures

Visual Facts


Primary / Proper / Traditional Name20 G. Eridani
Alternative NamesHD 17006, HIP 12611
Spectral TypeG8IV
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeSubgiant Star
ColourWhite to Yellow
GalaxyMilky Way
ConstellationEridanus
Absolute Magnitude 3.03 / 3.00
Visual / Apparent Magnitude6.09
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)02h 42m 08.44
Declination (Dec.)-46° 31` 27.2
Galactic Latitude-60.83 degrees
Galactic Longitude261.96 degrees
1997 Distance from Earth24.47 Parallax (milliarcseconds)
 133.29 Light Years
 40.87 Parsecs
2007 Distance from Earth24.07 Parallax (milliarcseconds)
 135.51 Light Years
 41.55 Parsecs
 8,570,242.98 Astronomical Units
Galacto-Centric Distance24,145.87 Light Years / 7,403.00 Parsecs
Proper Motion Dec.-94.41 ± 0.23 milliarcseconds/year
Proper Motion RA.9.99 ± 0.31 milliarcseconds/year
B-V Index0.87
Radial Velocity13.00 ± 2.90 km/s
Iron Abundance0.22 ± 0.06 Fe/H
Eccentricity0.13
Semi-Major Axis7206.00
Stellar Luminosity (Lsun)6.86

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Estimated Calculated Facts


Radius (x the Sun)2.98
Effective Temperature5,118 Kelvin

Sources and Links


SIMBAD SourceLink

Related Stars


Comments and Questions

There's no register feature and no need to give an email address if you don't need to. All messages will be reviewed before being displayed. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment.

   
x
This website is using cookies. More info. That's Fine