Universe Guide


Ogma - HD149026 - HIP80838

Ogma is a white to yellow star that can be located in the constellation of Hercules. It is calculated at being 2.000 Billion Years old. This information comes from ExoPlanet. HIP80838 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD149026.

Location of Ogma

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 Ogma, the location is 16h 30m 29.68 and +38d20`49.8 .

Proper Motion of Ogma

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 053.07 ± 000.59 towards the north and -076.27 ± 000.70 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Metallicity, Age, Mass, Radius) of Ogma

Ogma has a spectral type of G0. This means the star is a white to yellow star. The star has a B-V Colour Index of 0.61 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,852 Kelvin.

Ogma has been calculated as 1.68 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,166,119.79.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 0.360000, 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 2.00 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.

Ogma Apparent and Absolute Magnitudes

Ogma has an apparent magnitude of 8.15 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 3.67 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.65. 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 Ogma

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 12.68 which gave the calculated distance to Ogma as 257.23 light years away from Earth or 78.86 parsecs. It would take a spaceship travelling at the speed of light, 257.23 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 12.59 which put Ogma at a distance of 259.07 light years or 79.43 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.

Ogma Facts

Alternative Names

Traditional NameOgma
Hipparcos Library I.D.80838
Bonner DurchmusterungBD+38 2787
Henry Draper Designation149026

Visual Facts

Star Type star
Age2.000 Billions of Years
Absolute Magnitude3.67 / 3.65
Apparent Magnitude8.15
Right Ascension (R.A.)16h 30m 29.68
Declination (Dec.)+38d20`49.8
1997 Distance from Earth12.68 Parallax (milliarcseconds)
 257.23 Light Years
 78.86 Parsecs
2007 Revised Distance from Earth12.59 Parallax (milliarcseconds)
 259.07 Light Years
 79.43 Parsecs
Proper Motion Dec.53.07 ± 0.59 milliarcseconds/year
Proper Motion RA.-76.27 ± 0.70 milliarcseconds/year
B-V Index0.61
Spectral TypeG0
Colour(G) White to Yellow

Estimated Facts

Radius (x the Sun)1.68
Calculated Effective Temperature5,852 Kelvin
Mass Compared to the Sun1.00

Sources and Links

SIMBAD SourceLink

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