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SX Cassiopeiae - HD232121 - HIP871

SX Cassiopeiae is a blue eclipsing binary system giant star that can be located in the constellation of Cassiopeia. The star can not be seen by the naked eye, you need a telescope to see it.

HIP871 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD232121.

SX Cassiopeiae has alternative name(s), SX_Cas.

Location of SX Cassiopeiae

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 SX Cassiopeiae, the location is 00h 10m 42.07 and +54d53`29.4 .

Proper Motion of SX Cassiopeiae

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 -0.88 ± 1.79 miliarcseconds/year towards the north and 7.48 ± 2.62 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of SX Cassiopeiae

SX Cassiopeiae has a spectral type of B7IIIe+K3III. This means the star is a blue giant star. The star has a B-V Colour Index of 0.67 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,656 Kelvin.

SX Cassiopeiae Radius has been calculated as being 8.99 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 6,257,017.36.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.70. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

SX Cassiopeiae Apparent and Absolute Magnitudes

SX Cassiopeiae has an apparent magnitude of 8.97 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 0.17 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.10. 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 SX Cassiopeiae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.74 which gave the calculated distance to SX Cassiopeiae as 1874.50 light years away from Earth or 574.71 parsecs. It would take a spaceship travelling at the speed of light, 1874.50 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 4.23 which put SX Cassiopeiae at a distance of 771.07 light years or 236.41 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 SX Cassiopeiae

The star is a eclipsing binary system Beta Lyrae (Sheliak) 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. SX Cassiopeiae brightness ranges from a magnitude of 10.000 to a magnitude of 9.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

SX Cassiopeiae Facts

Alternative Names

Traditional/Proper NameSX Cassiopeiae
Short NameSX Cas
Hipparcos Library I.D.871
Bonner DurchmusterungBDD+54 7
Henry Draper Designation232121

Visual Facts

Star Typegiant star
Absolute Magnitude0.17 / 2.10
Visual / Apparent Magnitude8.97
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)00h 10m 42.07
Declination (Dec.)+54d53`29.4
Galactic Latitude-7.51 degrees
Galactic Longitude117.04 degrees
1997 Distance from Earth1.74 Parallax (milliarcseconds)
 1874.50 Light Years
 574.71 Parsecs
2007 Revised Distance from Earth4.23 Parallax (milliarcseconds)
 771.07 Light Years
 236.41 Parsecs
Proper Motion Dec.-0.88 ± 1.79 milliarcseconds/year
Proper Motion RA.7.48 ± 2.62 milliarcseconds/year
B-V Index0.67
Radial Velocity-6.50 ± 0.30 km/s
Spectral TypeB7IIIe+K3III
Colour(B) blue

Variable Star Details

Variable Star ClassEclipsing binary system
Variable Star TypeBeta Lyrae (Sheliak)
Variable Magnitude Range (Brighter - Dimmer)9.000 - 10.000

Estimated Facts

Calculated Effective Temperature5,656 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
232121+54 7.0A8.900008.00000-4.00000A7White
B1966

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