Universe Guide

AR Doradus

AR Doradus Facts

AR Doradus's Alternative Names

HIP24221 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD34349.

AR Doradus has alternative name(s) :- , AR Dor.

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

Location of AR Doradus

The location of the main sequence 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 AR Doradus, the location is 05h 12m 03.01 and -65° 10` 33.1 .

Radial Velocity and Proper Motion of AR Doradus

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 58.88 ± 0.34 milliarcseconds/year towards the north and 39.88 ± 0.36 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 62.80 km/s with an error of about 23.20 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.

AR Doradus 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 4.92 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature, Age) of AR Doradus

AR Doradus Colour and Temperature

AR Doradus has a spectral type of F5V. This means the star is a yellow to white main sequence star. The star has a B-V Colour Index of 0.43 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,590 Kelvin.

AR Doradus Radius

Radius has been calculated as being 1.82 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,269,368.87.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 1.72. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is 0.06 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

The stars age according to Hipparcos data files put the star at an age of about 2.00 Billion years old but could be between 1.70 and 2.20 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

AR Doradus Apparent and Absolute Magnitudes

AR Doradus has an apparent magnitude of 7.03 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 2.97 If you used the 2007 Parallax value, you would get an absolute magnitude of 3.10. 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 AR Doradus

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 15.26 which gave the calculated distance to AR Doradus as 213 light years away from Earth or 65 parsecs. If you want that in miles, it is 142,841,341,977.

In 2007, Hipparcos data was revised with a new parallax of 16.27 which put AR Doradus at a distance of 200 light years or 61 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 12,582,065.51 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.

The star's Galacto-Centric Distance is 7,396.00 Parsecs or 24,123.04 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to AR Doradus

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 A380736182,232,779.00
Speed of Sound (Mach 1)767.269174,806,131.00
Concorde (Mach 2)1,534.5487,402,951.00
New Horizons Probe33,0004,064,343.00
Speed of Light670,616,629.00200.00

Variable Type of AR Doradus

The star is a eclipsing binary sys Eclipsing 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. This is a some uncertainty as to the type but the type mentioned is the current variable star classification for this star. AR Doradus brightness ranges from a magnitude of 7.196 to a magnitude of 7.120 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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 AR Doradus Facts and Figures

Visual Facts

Primary / Proper / Traditional NameAR Doradus
Alternative NamesHD 34349, HIP 24221, AR Dor
Spectral TypeF5V
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star Type Main Sequence Dwarf Star
ColourYellow - White
GalaxyMilky Way
Age2.00 Billion Years Old
Age Range1.70 - 2.20 Billion Years Old
Absolute Magnitude 2.97 / 3.10
Visual / Apparent Magnitude7.03
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)05h 12m 03.01
Declination (Dec.)-65° 10` 33.1
Galactic Latitude-34.81 degrees
Galactic Longitude275.29 degrees
1997 Distance from Earth15.26 Parallax (milliarcseconds)
 213 Light Years
 65 Parsecs
2007 Distance from Earth16.27 Parallax (milliarcseconds)
 200 Light Years
 61 Parsecs
 12,582,065.51 Astronomical Units
Galacto-Centric Distance24,123.04 Light Years / 7,396.00 Parsecs
Proper Motion Dec.58.88 ± 0.34 milliarcseconds/year
Proper Motion RA.39.88 ± 0.36 milliarcseconds/year
B-V Index0.43
Radial Velocity62.80 ± 23.20 km/s
Iron Abundance0.06 ± 9.99 Fe/H
Semi-Major Axis5085.00
Stellar Luminosity (Lsun)4.92

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassEclipsing binary sys
Variable Star TypeEclipsing probably
Mean Variability Period in Days0.118
Variable Magnitude Range (Brighter - Dimmer)7.120 - 7.196

Estimated Calculated Facts

Radius (x the Sun)1.72
Effective Temperature6,590 Kelvin

Sources and Links

SIMBAD SourceLink

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