Universe Guide


HR 4523 - HD102365 - HIP57443

HR 4523 is a white to yellow main sequence dwarf star that can be located in the constellation of Centaurus. It is calculated at being 9.000 Billion Years old. This information comes from ExoPlanet. HIP57443 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD102365. The Id of the star in the Gould Star Catalogue is 66. 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.

Location of HR 4523

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 HR 4523, the location is 11h 46m 32.25 and -40d30`04.8 .

Proper Motion of HR 4523

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 403.67 ± 000.15 towards the north and -1,530.99 ± 000.22 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Age, Mass, Radius) of HR 4523

HR 4523 has a spectral type of G3/G5V. This means the star is a white to yellow main sequence dwarf star. The star has a B-V Colour Index of 0.66 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,689 Kelvin.

HR 4523 has been calculated as 0.93 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 650,528.44.km. The star's solar mass is 1.00 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is -0.280000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

The star is believed to be about 9.00 Billion years old. To put in context, the Sun is believed to be about five billion years old and the Universe is about 13.8 billion years old.

HR 4523 Apparent and Absolute Magnitudes

HR 4523 has an apparent magnitude of 4.89 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 5.06 If you used the 2007 Parallax value, you would get an absolute magnitude of 5.07. 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 HR 4523

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 108.23 which gave the calculated distance to HR 4523 as 30.14 light years away from Earth or 9.24 parsecs. It would take a spaceship travelling at the speed of light, 30.14 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 108.45 which put HR 4523 at a distance of 30.07 light years or 9.22 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.

HR 4523 Facts

Alternative Names

Traditional NameHR 4523
Hipparcos Library I.D.57443
Gould I.D.66
Henry Draper Designation102365

Visual Facts

Star Typemain sequence dwarf star
Age9.000 Billions of Years
Absolute Magnitude5.06 / 5.07
Apparent Magnitude4.89
Right Ascension (R.A.)11h 46m 32.25
Declination (Dec.)-40d30`04.8
1997 Distance from Earth108.23 Parallax (milliarcseconds)
 30.14 Light Years
 9.24 Parsecs
2007 Revised Distance from Earth108.45 Parallax (milliarcseconds)
 30.07 Light Years
 9.22 Parsecs
Proper Motion Dec.403.67 ± 0.15 milliarcseconds/year
Proper Motion RA.-1530.99 ± 0.22 milliarcseconds/year
B-V Index0.66
Spectral TypeG3/G5V
Colour(G) White to Yellow

Estimated Facts

Radius (x the Sun)0.93
Calculated Effective Temperature5,689 Kelvin
Mass Compared to the Sun1.00

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
102365-39 7301.2A5.80000-1532.00000400.00000G5Yellow

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