Universe Guide

ZZ Cassiopeiae

ZZ Cassiopeiae Facts

ZZ Cassiopeiae's Alternative Names

HIP2644 is the reference name for the star in the Hipparcos Star Catalogue.

ZZ Cassiopeiae has alternative name(s) :- ZZ Cas, ZZ Cas.

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

Location of ZZ Cassiopeiae

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 ZZ Cassiopeiae, the location is 00h 33m 30.39 and +62° 30` 40.2 .

Radial Velocity and Proper Motion of ZZ Cassiopeiae

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 -0.91 ± 1.38 milliarcseconds/year towards the north and -3.28 ± 2.01 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 -45.00 km/s with an error of about 10.00 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 ZZ Cassiopeiae

ZZ Cassiopeiae Colour and Temperature

ZZ Cassiopeiae has a spectral type of B3. This means the star is a blue variable star. The star has a B-V Colour Index of 0.4 which means the star's temperature is about 6,398 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu at being .

ZZ Cassiopeiae Radius

Radius has been calculated as being 1.31 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 914,664.77.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 1.81. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

ZZ Cassiopeiae Apparent and Absolute Magnitudes

ZZ Cassiopeiae has an apparent magnitude of 11.11 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 3.81 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.12. 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 ZZ Cassiopeiae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.47 which gave the calculated distance to ZZ Cassiopeiae as 939.95 light years away from Earth or 288.18 parsecs. If you want that in miles, it is 630,346,100,429.

In 2007, Hipparcos data was revised with a new parallax of 2.52 which put ZZ Cassiopeiae at a distance of 1294.30 light years or 396.83 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 81,851,492.71 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.

Travel Time to ZZ Cassiopeiae

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A3807361,179,319,433.31
Speed of Sound (Mach 1)767.2691,131,257,880.76
Concorde (Mach 2)1,534.54565,628,203.18
New Horizons Probe33,00026,302,397.06
Speed of Light670,616,629.001,294.30

Variable Type of ZZ Cassiopeiae

The star is a eclipsing 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. ZZ Cassiopeiae brightness ranges from a magnitude of 11.580 to a magnitude of 10.984 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.2 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.

Hide Explanations
Show GridLines

Additional ZZ Cassiopeiae Facts and Figures

Visual Facts

Primary / Proper / Traditional NameZZ Cassiopeiae
Alternative NamesZZ Cas, HIP 2644, ZZ Cas
Spectral TypeB3
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
GalaxyMilky Way
Absolute Magnitude 3.81 / 3.12
Visual / Apparent Magnitude11.11
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)00h 33m 30.39
Declination (Dec.)+62° 30` 40.2
Galactic Latitude-0.29 degrees
Galactic Longitude120.86 degrees
1997 Distance from Earth3.47 Parallax (milliarcseconds)
 939.95 Light Years
 288.18 Parsecs
2007 Distance from Earth2.52 Parallax (milliarcseconds)
 1294.30 Light Years
 396.83 Parsecs
 81,851,492.71 Astronomical Units
Proper Motion Dec.-0.91 ± 1.38 milliarcseconds/year
Proper Motion RA.-3.28 ± 2.01 milliarcseconds/year
B-V Index0.40
Radial Velocity-45.00 ± 10.00 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassEclipsing
Variable Star TypeBeta Lyrae (Sheliak)
Mean Variability Period in Days1.244
Variable Magnitude Range (Brighter - Dimmer)10.984 - 11.580

Estimated Calculated Facts

Radius (x the Sun)1.81
Effective Temperature6,398 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

There's no register feature and no need to give an email address if you don't need to. All messages will be reviewed before being displayed. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment.

You can decline to give a name which if that is the case, the comment will be attributed to a random star. A name is preferred even if its a random made up one by yourself.

This website is using cookies. More info. That's Fine