Universe Guide

RS Scorpii

RS Scorpii Facts

RS Scorpii's Alternative Names

HIP82833 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD152476.

RS Scorpii has alternative name(s) :- RS Sco, RS Sco.

More details on objects' alternative names can be found at Star Names .

Location of RS Scorpii

The location of the variable star in the night sky 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 object is compared to the celestial equator and is expressed in degrees. For RS Scorpii, the location is 16h 55m 37.80 and -45° 06` 10.4 .

Radial Velocity and Proper Motion of RS Scorpii

Proper Motion

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 -39.87 ± 1.68 milliarcseconds/year towards the north and 19.99 ± 2.27 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 7.40 km/s with an error of about 3.30 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties (Colour, Temperature) of RS Scorpii

RS Scorpii Colour and Temperature

RS Scorpii has a spectral type of M6e. This means the star is a red variable star. The star has a B-V Colour Index of 1.5 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,014 Kelvin.

RS Scorpii Radius

Radius has been calculated as being 5.49 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,821,257.39.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.00. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

RS Scorpii Apparent and Absolute Magnitudes

RS Scorpii has an apparent magnitude of 10.32 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 2.73 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.04. 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 RS Scorpii

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.04 which gave the calculated distance to RS Scorpii as 1072.91 light years away from Earth or 328.95 parsecs. It would take a spaceship travelling at the speed of light, 1072.91 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 5.54 which put RS Scorpii at a distance of 588.74 light years or 180.51 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.

Using the 2007 distance, the star is roughly 37,232,600.74 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

Variable Type of RS Scorpii

The star is a pulsating Omicron Ceti 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. RS Scorpii brightness ranges from a magnitude of 10.594 to a magnitude of 6.141 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 319.2 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.

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Additional RS Scorpii Facts and Figures

Visual Facts

Primary / Proper / Traditional NameRS Scorpii
Alternative NamesRS Sco, HD 152476, HIP 82833, RS Sco
Spectral TypeM6e
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
GalaxyMilky Way
Absolute Magnitude 2.73 / 4.04
Visual / Apparent Magnitude10.32
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)16h 55m 37.80
Declination (Dec.)-45° 06` 10.4
Galactic Latitude-1.08 degrees
Galactic Longitude341.08 degrees
1997 Distance from Earth3.04 Parallax (milliarcseconds)
 1072.91 Light Years
 328.95 Parsecs
2007 Distance from Earth5.54 Parallax (milliarcseconds)
 588.74 Light Years
 180.51 Parsecs
 37,232,600.74 Astronomical Units
Proper Motion Dec.-39.87 ± 1.68 milliarcseconds/year
Proper Motion RA.19.99 ± 2.27 milliarcseconds/year
B-V Index1.50
Radial Velocity7.40 ± 3.30 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeOmicron Ceti
Mean Variability Period in Days319.200
Variable Magnitude Range (Brighter - Dimmer)6.141 - 10.594

Estimated Calculated Facts

Radius (x the Sun)3.00
Effective Temperature4,014 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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