Universe Guide

AY Centauri

AY Centauri Facts

  • AY Centauri is a pulsating variable star that can be located in the constellation of Centaurus. The description is based on the spectral class.
  • AY Centauri is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (K0) of the star, the star's colour is orange to 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 12544.74 light years away from us. Distance

AY Centauri's Alternative Names

HIP55726 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD99325.

AY Centauri has alternative name(s) :- AY Cen, AY Cen.

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

Location of AY Centauri

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 AY Centauri, the location is 11h 25m 05.76 and -60° 44` 04.7 .

Radial Velocity and Proper Motion of AY Centauri

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 1.73 ± 0.91 milliarcseconds/year towards the north and -7.09 ± 1.29 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 -15.50000 km/s with an error of about 0.90 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 AY Centauri

AY Centauri Temperature and Colour

Based on the star's spectral type of K0 , AY Centauri's colour and type is orange to red variable star. The star has a B-V Colour Index of 0.97 which means the star's temperature is about 5,038 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

AY Centauri Radius

AY Centauri Apparent and Absolute Magnitudes

AY Centauri has an apparent magnitude of 8.76 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 If you used the 2007 Parallax value, you would get an absolute magnitude of -4.17. 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 AY Centauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as -0.24000 which gave the calculated distance to AY Centauri as -13590.14 light years away from Earth or -4166.67 parsecs. If you want that in miles, it is about -79,891,341,829,117,505.61, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 0.26000 which put AY Centauri at a distance of 12544.74 light years or 3846.15 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 793,319,856.62 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 AY Centauri

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 A38073611,430,314,199.02
Speed of Sound (Mach 1)767.26910,964,487,357.73
Concorde (Mach 2)1,534.545,482,236,533.74
New Horizons Probe33,000254,930,643.95
Speed of Light670,616,629.0012,544.74

Variable Type of AY Centauri

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. AY Centauri brightness ranges from a magnitude of 9.235 to a magnitude of 8.670 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 5.3 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 AY Centauri Facts and Figures

Visual Facts

Primary / Proper / Traditional NameAY Centauri
Alternative NamesAY Cen, HD 99325, HIP 55726, AY Cen
Spectral TypeK0
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeVariable Star
ColourOrange to Red
GalaxyMilky Way
Absolute Magnitude / -4.17
Visual / Apparent Magnitude8.76
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)11h 25m 05.76
Declination (Dec.)-60° 44` 04.7
Galactic Latitude0.38842757 degrees
Galactic Longitude292.57098507 degrees
1997 Distance from Earth-0.24000 Parallax (milliarcseconds)
 -13590.14 Light Years
 -4166.67 Parsecs
2007 Distance from Earth0.26000 Parallax (milliarcseconds)
 12544.74 Light Years
 3846.15 Parsecs
 793,319,856.62 Astronomical Units
Proper Motion Dec.1.73000 ± 0.91000 milliarcseconds/year
Proper Motion RA.-7.09000 ± 1.29000 milliarcseconds/year
B-V Index0.97
Radial Velocity-15.50000 ± 0.90 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Cepheid
Mean Variability Period in Days5.309
Variable Magnitude Range (Brighter - Dimmer)8.670 - 9.235

Estimated Calculated Facts

Effective Temperature5,038 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Comments and Questions

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