Universe Guide

AA Cassiopeiae

AA Cassiopeiae Facts

  • AA Cassiopeiae is a pulsating giant star that can be located in the constellation of Cassiopeia. The description is based on the spectral class.
  • AA Cassiopeiae is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (M6III) of the star, the star's colour is red .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 776.58 light years away from us. Distance

AA Cassiopeiae's Alternative Names

HIP6191 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD7861.

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

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+55 290.

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

Location of AA Cassiopeiae

The location of the giant 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 AA Cassiopeiae, the location is 01h 19m 25.66 and +56° 19` 45.1 .

Radial Velocity and Proper Motion of AA 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 -4.62 ± 1.19 milliarcseconds/year towards the north and -0.12 ± 1.87 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 5.00000 km/s with an error of about 4.50 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 of AA Cassiopeiae

AA Cassiopeiae Colour and Temperature

Based on the star's spectral type of M6III , AA Cassiopeiae's colour and type is red giant star. The star has a B-V Colour Index of 1.4 which means the star's temperature is about 4,159 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

AA Cassiopeiae Radius

AA Cassiopeiae estimated radius has been calculated as being 10.25 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 7,135,066.29.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 8.768196009500481752696445512. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

AA Cassiopeiae Apparent and Absolute Magnitudes

AA Cassiopeiae has an apparent magnitude of 8.44 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 1.22 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.56. 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 AA Cassiopeiae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.59000 which gave the calculated distance to AA Cassiopeiae as 908.53 light years away from Earth or 278.55 parsecs. If you want that in miles, it is about 5,340,907,510,298,505.19, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 4.20000 which put AA Cassiopeiae at a distance of 776.58 light years or 238.10 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.

Using the 2007 distance, the star is roughly 49,111,308.16 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 AA 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 A380736707,591,659.98
Speed of Sound (Mach 1)767.269678,754,728.46
Concorde (Mach 2)1,534.54339,376,921.91
New Horizons Probe33,00015,781,438.23
Speed of Light670,616,629.00776.58

Variable Type of AA Cassiopeiae

The star is a pulsating Slow Irregular 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. AA Cassiopeiae brightness ranges from a magnitude of 8.449 to a magnitude of 7.663 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.7 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 AA Cassiopeiae Facts and Figures

Visual Facts

Primary / Proper / Traditional NameAA Cassiopeiae
Alternative NamesHD 7861, HIP 6191, BD+55 290, AA Cas
Spectral TypeM6III
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeGiant Star
GalaxyMilky Way
Absolute Magnitude 1.22 / 1.56
Visual / Apparent Magnitude8.44
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)01h 19m 25.66
Declination (Dec.)+56° 19` 45.1
Galactic Latitude-6.33065761 degrees
Galactic Longitude126.82854821 degrees
1997 Distance from Earth3.59000 Parallax (milliarcseconds)
 908.53 Light Years
 278.55 Parsecs
2007 Distance from Earth4.20000 Parallax (milliarcseconds)
 776.58 Light Years
 238.10 Parsecs
 49,111,308.16 Astronomical Units
Proper Motion Dec.-4.62000 ± 1.19000 milliarcseconds/year
Proper Motion RA.-0.12000 ± 1.87000 milliarcseconds/year
B-V Index1.4
Radial Velocity5.00000 ± 4.50 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSlow Irregular
Mean Variability Period in Days0.706
Variable Magnitude Range (Brighter - Dimmer)7.663 - 8.449

Estimated Calculated Facts

Radius (x the Sun)8.77
Effective Temperature4,159 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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