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236 G. Hya - HD91889 - HIP51933

236 G. Hya is a blue to white main sequence dwarf star that can be located in the constellation of Hydra. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it. The star has an estimated age of 4.10 Billion of Years but could be as young as 3.90 to 6.80 according to Hipparcos.

HIP51933 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD91889. The Id of the star in the Gould Star Catalogue is 236. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major. The Gliese ID of the star is Gliese GL398.1. 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.

Location of 236 G. Hya

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 236 G. Hya, the location is 10h 36m 32.22 and -12d13`42.6 .

Proper Motion of 236 G. Hya

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 -672.57 ± 0.27 miliarcseconds/year towards the north and 268.46 ± 0.37 miliarcseconds/year east if we saw them in the horizon.

236 G. Hya 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 2.0000000 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, Age, Radius) of 236 G. Hya

236 G. Hya has a spectral type of F7V. This means the star is a blue to white main sequence dwarf star. The star is 7404.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24149.1339897600000000s. The star has a B-V Colour Index of 0.52 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,202 Kelvin.

236 G. Hya Radius has been calculated as being 1.43 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 996,064.34.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.46. 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 0.01 Fe/H with the Sun has a value of 1 to put it into context.

The stars age according to Hipparcos data files put the star at an age of about 4.10 Billion years old but could be between 3.90 and 6.80 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

236 G. Hya Apparent and Absolute Magnitudes

236 G. Hya has an apparent magnitude of 5.71 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 3.76 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.71. 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 236 G. Hya

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 40.67 which gave the calculated distance to 236 G. Hya as 80.20 light years away from Earth or 24.59 parsecs. It would take a spaceship travelling at the speed of light, 80.20 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 39.88 which put 236 G. Hya at a distance of 81.79 light years or 25.08 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 7,404.00 Parsecs or 24,149.13 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.

236 G. Hya Facts

Alternative Names

Traditional/Proper Name236 G. Hya
Hipparcos Library I.D.51933
Bonner DurchmusterungBDD-11 2918
Gould I.D.236
Gliese ID398.1
Henry Draper Designation91889

Visual Facts

Star Typemain sequence dwarf star
Age4.10 Billion Years Old
Age Range3.90 - 6.80 Billion Years Old
Absolute Magnitude3.76 / 3.71
Visual / Apparent Magnitude5.71
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)10h 36m 32.22
Declination (Dec.)-12d13`42.6
Galactic Latitude38.82 degrees
Galactic Longitude258.79 degrees
1997 Distance from Earth40.67 Parallax (milliarcseconds)
 80.20 Light Years
 24.59 Parsecs
2007 Revised Distance from Earth39.88 Parallax (milliarcseconds)
 81.79 Light Years
 25.08 Parsecs
Galacto-Centric Distance24,149.13 Light Years / 7,404.00 Parsecs
Proper Motion Dec.-672.57 ± 0.27 milliarcseconds/year
Proper Motion RA.268.46 ± 0.37 milliarcseconds/year
B-V Index0.52
Radial Velocity-6.33 ± 0.15 km/s
Iron Abundance-0.22 ± 0.01 Fe/H
Spectral TypeF7V
Colour(F) blue to white

Estimated Facts

Luminosity (x the Sun)2.0000000
Calculated Effective Temperature6,202 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
91889-11 2918.0A5.40000262.00000-680.00000F8Yellow/White
B10.500001958

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