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V636 Cassiopeiae - HD9250 - HIP7192

V636 Cassiopeiae is a white to yellow pulsating very luminous supergiant 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.

HIP7192 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD9250.

V636 Cassiopeiae has alternative name(s), V636_Cas.

Location of V636 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 V636 Cassiopeiae, the location is 01h 32m 43.23 and +63d35`37.7 .

Proper Motion of V636 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 0.03 ± 0.42 miliarcseconds/year towards the north and -0.54 ± 0.62 miliarcseconds/year east if we saw them in the horizon.

V636 Cassiopeiae Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 9600.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Radius) of V636 Cassiopeiae

V636 Cassiopeiae has a spectral type of G0Ib. This means the star is a white to yellow supergiant star. The star has a B-V Colour Index of 1.3 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,386 Kelvin.

V636 Cassiopeiae Radius has been calculated as being 34.42 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 23,947,858.11.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 29.84. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V636 Cassiopeiae Apparent and Absolute Magnitudes

V636 Cassiopeiae has an apparent magnitude of 7.18 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 -1.64 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.33. 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 V636 Cassiopeiae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.72 which gave the calculated distance to V636 Cassiopeiae as 1896.30 light years away from Earth or 581.40 parsecs. It would take a spaceship travelling at the speed of light, 1896.30 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 1.99 which put V636 Cassiopeiae at a distance of 1639.01 light years or 502.51 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.

Variable Type of V636 Cassiopeiae

The star is a pulsating Delta Cepheid 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. V636 Cassiopeiae brightness ranges from a magnitude of 7.000 to a magnitude of 7.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 8.0 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.

V636 Cassiopeiae Facts

Alternative Names

Traditional/Proper NameV636 Cassiopeiae
Short NameV636 Cas
Hipparcos Library I.D.7192
Bonner DurchmusterungBDD+62 264
Henry Draper Designation9250

Visual Facts

Star Typesupergiant star
Absolute Magnitude-1.64 / -1.33
Visual / Apparent Magnitude7.18
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)01h 32m 43.23
Declination (Dec.)+63d35`37.7
Galactic Latitude1.09 degrees
Galactic Longitude127.50 degrees
1997 Distance from Earth1.72 Parallax (milliarcseconds)
 1896.30 Light Years
 581.40 Parsecs
2007 Revised Distance from Earth1.99 Parallax (milliarcseconds)
 1639.01 Light Years
 502.51 Parsecs
Proper Motion Dec.0.03 ± 0.42 milliarcseconds/year
Proper Motion RA.-0.54 ± 0.62 milliarcseconds/year
B-V Index1.30
Radial Velocity-25.00 ± 0.30 km/s
Spectral TypeG0Ib
Colour(G) White to Yellow

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Cepheid
Mean Variability Period in Days8.000

Estimated Facts

Luminosity (x the Sun)9,600.0000000
Calculated Effective Temperature4,386 Kelvin

Sources and Links

SIMBAD SourceLink

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