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Epsilon Scuti - HD173009 - HIP91845

Epsilon Scuti is a white to yellow luminous giant star that can be located in the constellation of Scutum. Epsilon Scuti is the Bayer Classification for the star. HIP91845 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD173009.

Location of Epsilon Scuti

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 Epsilon Scuti, the location is 18h 43m 31.24 and -08d16`30.9 .

Proper Motion of Epsilon Scuti

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 009.11 ± 000.33 towards the north and 021.06 ± 000.64 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Epsilon Scuti

Epsilon Scuti has a spectral type of G8II. This means the star is a white to yellow luminous giant star. The star has a B-V Colour Index of 1.11 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,742 Kelvin.

Epsilon Scuti has been calculated as 23.39 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 16,273,310.95.km.

Epsilon Scuti Apparent and Absolute Magnitudes

Epsilon Scuti has an apparent magnitude of 4.88 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 -1.14 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.21. 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 Epsilon Scuti

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.24 which gave the calculated distance to Epsilon Scuti as 522.70 light years away from Earth or 160.26 parsecs. It would take a spaceship travelling at the speed of light, 522.70 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 6.06 which put Epsilon Scuti at a distance of 538.22 light years or 165.02 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.

Epsilon Scuti Facts

Alternative Names

Bayer DesignationEpsilon Scuti
Hipparcos Library I.D.91845
Bonner DurchmusterungBD-08 4686
Henry Draper Designation173009

Visual Facts

Star Typeluminous giant star
Absolute Magnitude-1.14 / -1.21
Apparent Magnitude4.88
Right Ascension (R.A.)18h 43m 31.24
Declination (Dec.)-08d16`30.9
1997 Distance from Earth6.24 Parallax (milliarcseconds)
 522.70 Light Years
 160.26 Parsecs
2007 Revised Distance from Earth6.06 Parallax (milliarcseconds)
 538.22 Light Years
 165.02 Parsecs
Proper Motion Dec.9.11 ± 0.33 milliarcseconds/year
Proper Motion RA.21.06 ± 0.64 milliarcseconds/year
B-V Index1.11
Spectral TypeG8II
Colour(G) White to Yellow

Estimated Facts

Radius (x the Sun)23.39
Calculated Effective Temperature4,742 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
173009-08 4686.0A5.1000020.000007.00000G5Yellow
B14.600001910
C13.700001910
D14.700001934

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