Universe Guide


103 G. Sagittarii - HD173928 - HIP92301

103 G. Sagittarii is a blue main sequence dwarf star that can be located in the constellation of Sagittarius. HIP92301 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD173928. The Id of the star in the Gould Star Catalogue is 103. 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 103 G. Sagittarii

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 103 G. Sagittarii, the location is 18h 48m 45.41 and -18d36`04.2 .

Proper Motion of 103 G. Sagittarii

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 003.08 ± 000.78 towards the north and 002.80 ± 001.11 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 103 G. Sagittarii

103 G. Sagittarii has a spectral type of A1V + K1III. This means the star is a blue coloured main sequence dwarf star. The star has a B-V Colour Index of 0.9 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,052 Kelvin.

103 G. Sagittarii has been calculated as 15.20 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 10,579,517.44.km.

103 G. Sagittarii Apparent and Absolute Magnitudes

103 G. Sagittarii has an apparent magnitude of 6.46 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 -0.48 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.01. 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 103 G. Sagittarii

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.10 which gave the calculated distance to 103 G. Sagittarii as 795.52 light years away from Earth or 243.90 parsecs. In 2007, Hipparcos data was revised with a new parallax of 3.20 which put 103 G. Sagittarii at a distance of 1019.26 light years or 312.5 parsecs.

It would take a spaceship travelling at the speed of light, 795.52 years using the 1997 distance to get there. We don't have the technology or spaceship that can carry people over that distance yet.

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.

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103 G. Sagittarii Facts

Alternative Names

Traditional Name103 G. Sagittarii
Hipparcos Library I.D.92301
Bonner DurchmusterungBD-18 5079
Gould I.D.103
Henry Draper Designation173928

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude-0.48 / -1.01
Apparent Magnitude6.46
Right Ascension (R.A.)18h 48m 45.41
Declination (Dec.)-18d36`04.2
1997 Distance from Earth4.10 Parallax (milliarcseconds)
 795.52 Light Years
 243.90 Parsecs
2007 Distance from Earth3.20 Parallax (milliarcseconds)
 1019.26 Light Years
 312.5 Parsecs
Proper Motion Dec.3.08 ± 0.78 milliarcseconds/year
Proper Motion RA.2.80 ± 1.11 milliarcseconds/year
B-V Index0.90
Spectral TypeA1V + K1III
Colour(A) blue

Estimated Facts

Radius (x the Sun)15.20
Calculated Effective Temperature5,052 Kelvin

Sources and Links

SIMBAD SourceLink

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
173928-18 5079.0A7.00000-7.00000-3.00000A0White

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