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Terebellum, Omega Sagittarii, 58 Sagittarii, HD188376, HIP98066

Terebellum (Omega Sagittarii) is a white to yellow giant star that can be located in the constellation of Sagittarius. Terebellum is the brightest star in Sagittarius based on the Hipparcos 2007 apparent magnitude. 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 2.60 Billion of Years but could be as young as 2.30 to 2.90 according to Hipparcos.

Omega Sagittarii is the Bayer Classification for the star. HIP98066 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD188376. The Id of the star in the Gould Star Catalogue is 248. 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 GL770.1. 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 Terebellum

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 Terebellum, the location is 19h 55m 50.23 and -26d17`58.9 .

Proper Motion of Terebellum

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 62.39 ± 1.50 miliarcseconds/year towards the north and 209.41 ± 2.66 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Age, Radius) of Terebellum

Terebellum has a spectral type of G3/G5III. This means the star is a white to yellow giant star. The star is 7377.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24061.0698868800000000s. The star has a B-V Colour Index of 0.74 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,446 Kelvin.

Terebellum Radius has been calculated as being 2.86 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,991,612.63.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.12. 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 0.03 with an error value of 0.02 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 2.60 Billion years old but could be between 2.30 and 2.90 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

Terebellum Apparent and Absolute Magnitudes

Terebellum has an apparent magnitude of 4.70 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 2.82 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.63. 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 Terebellum

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 42.03 which gave the calculated distance to Terebellum as 77.60 light years away from Earth or 23.79 parsecs. It would take a spaceship travelling at the speed of light, 77.60 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 38.48 which put Terebellum at a distance of 84.76 light years or 25.99 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 7,377.00 Parsecs or 24,061.07 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.

Terebellum Facts

Alternative Names

Traditional/Proper NameTerebellum
Flamsteed Name58 Sagittarii
Flamsteed Short Name58 Sgr
Bayer DesignationOmega Sagittarii
Hipparcos Library I.D.98066
Gould I.D.248
Gliese ID770.1
Henry Draper Designation188376

Visual Facts

Star Typegiant star
Age2.60 Billion Years Old
Age Range2.30 - 2.90 Billion Years Old
Absolute Magnitude2.82 / 2.63
Visual / Apparent Magnitude4.70
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)19h 55m 50.23
Declination (Dec.)-26d17`58.9
Galactic Latitude-25.04 degrees
Galactic Longitude14.87 degrees
1997 Distance from Earth42.03 Parallax (milliarcseconds)
 77.60 Light Years
 23.79 Parsecs
2007 Revised Distance from Earth38.48 Parallax (milliarcseconds)
 84.76 Light Years
 25.99 Parsecs
Galacto-Centric Distance24,061.07 Light Years / 7,377.00 Parsecs
Proper Motion Dec.62.39 ± 1.50 milliarcseconds/year
Proper Motion RA.209.41 ± 2.66 milliarcseconds/year
B-V Index0.74
Radial Velocity-39.14 ± 11.89 km/s
Iron Abundance0.03 ± 0.02 Fe/H
Spectral TypeG3/G5III
Colour(G) White to Yellow

Estimated Facts

Calculated Effective Temperature5,446 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Location of Terebellum in Sagittarius


Terebellum (Omega Sagittarii) Location in Sagittarius

The map was generated using Night Vision, an awesome free application by Brian Simpson.


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