Universe Guide


S Scuti, HD174325, HIP92442

S Scuti is a pulsating luminous giant star that can be located in the constellation of Scutum. S Scuti is the brightest star in Scutum based on the Hipparcos 2007 apparent magnitude. The star can not be seen by the naked eye, you need a telescope to see it.

HIP92442 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD174325.

S Scuti has alternative name(s), S Sct.

Location of S 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 S Scuti, the location is 18h 50m 20.03 and -07d54`27.4 .

Proper Motion of S 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 -4.55 ± 0.33 miliarcseconds/year towards the north and 7.92 ± 0.57 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Temperature, Radius) of S Scuti

S Scuti has a spectral type of C5II. This means the star is a luminous giant star. The star has a B-V Colour Index of 2.99 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 0 Kelvin. 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 -0.10 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

S Scuti Apparent and Absolute Magnitudes

S Scuti has an apparent magnitude of 6.82 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 -1.16 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.11. 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 S Scuti

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.53 which gave the calculated distance to S Scuti as 1289.18 light years away from Earth or 395.26 parsecs. It would take a spaceship travelling at the speed of light, 1289.18 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 2.59 which put S Scuti at a distance of 1259.32 light years or 386.10 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.

Variable Type of S Scuti

The star is a pulsating Semiregular late- (M, C, S or Me, Ce, Se) giants with poorly defined periodicity variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. S Scuti brightness ranges from a magnitude of 6.868 to a magnitude of 6.535 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.3 days (variability).

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.

S Scuti Facts

Alternative Names

Traditional/Proper NameS Scuti
Short NameS Sct
Hipparcos Library I.D.92442
Bonner DurchmusterungBD-08 4726
Henry Draper Designation174325

Visual Facts

Star Typeluminous giant star
Absolute Magnitude-1.16 / -1.11
Visual / Apparent Magnitude6.82
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)18h 50m 20.03
Declination (Dec.)-07d54`27.4
Galactic Latitude-3.35 degrees
Galactic Longitude25.76 degrees
1997 Distance from Earth2.53 Parallax (milliarcseconds)
 1289.18 Light Years
 395.26 Parsecs
2007 Revised Distance from Earth2.59 Parallax (milliarcseconds)
 1259.32 Light Years
 386.10 Parsecs
Proper Motion Dec.-4.55 ± 0.33 milliarcseconds/year
Proper Motion RA.7.92 ± 0.57 milliarcseconds/year
B-V Index2.99
Radial Velocity-0.20 ± 1.60 km/s
Iron Abundance-0.10 ± 9.99 Fe/H
Spectral TypeC5II

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemiregular late- (M, C, S or Me, Ce, Se) giants with poorly defined periodicity
Mean Variability Period in Days0.320
Variable Magnitude Range (Brighter - Dimmer)6.535 - 6.868

Estimated Facts

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
174325-08 4726.0A1.000002.00000NB

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