Algiedi Prima / Alpha Capricorni Facts (Type, Distance, Magnitude, Colour, Luminosity, Location & more)

Algiedi Prima Facts

• Algiedi Prima is a very luminous Supergiant Star less luminour Supergiant Star. Algiedi Prima is a G3IB supergiant star based on the spectral type that was recorded in the Hipparcos star catalogue.
• Algiedi Prima is a main star in the constellation Capricornus and makes up the constellation outline.
• Based on the spectral type (G3Ib) of the star, the Algiedi Prima colour is yellow .
• The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
• Algiedi Prima is a Binary or Multiple star system.
• Using the most recent figures given by the 2007 Hipparcos data, Algiedi Prima distance from Earth is 569.22 light years.

Algiedi Prima Location

The location of the supergiant 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 Algiedi Prima, the location is 20h 17m 38.86 and -12° 30` 29.6 .

Algiedi Prima Radial Velocity and Proper Motion

Algiedi Prima 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 1.28 ± 0.14 milliarcseconds/year towards the north and 22.98 ± 0.33 milliarcseconds/year east if we saw them in the horizon.

Algiedi Prima Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -26.70000 km/s with an error of about 0.40 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.

Algiedi Prima Physical Properties

Algiedi Prima Colour and Temperature

Based on the star's spectral type of G3Ib , Algiedi Prima's colour and type is yellow supergiant star. Based on the spectral type, we can deduce that the surface temperature of the star is in the order of between 5,000 and 6,000K based on the notes from Harvard University. To put this in context, the temperature of our Sun is about 5,778 Kelvin as said by Google.

Algiedi Prima 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 651.39 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Algiedi Prima Radius

Algiedi Prima estimated radius has been calculated as being 34.14 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 23,757,248.96.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 28.27. 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.

Algiedi Prima Apparent (Brightness) and Absolute Magnitudes

Algiedi Prima apparent magnitude is 4.30, this is a measure of the brightness of the star as seen from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, Algiedi Prima absolute magnitude is -2.32 If you used the 2007 Parallax value, Algiedi Prima absolute magnitude is -1.91.

Absolute Magnitude is the apparent magnitude of the star from a distance of 10 parsecs or 32.6 light years. This assumes that there is nothing in between the object and the viewer such as dust clouds. To really compare the brightness of the star, it is best to use Absolute rather than Apparent Magnitude.

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.

Algiedi Prima Distance from Earth

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.75000 which means Algiedi Prima distance from Earth is 686.66 light years away from Earth or 210.53 parsecs. If you want that in miles, it is about 4,036,616,898,750,257.64, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 5.73000 which puts Algiedi Prima distance from Earth as 569.22 light years or 174.52 parsecs. It should not be taken as though the star is moving closer or further away from Earth. It is purely that the distance was recalculated.

Using the 2007 distance, the star is roughly 35,997,083.16 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. The star's Galacto-Centric Distance is 7,266.00 Parsecs or 23,699.03 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Alternative Names and Meanings

• The Id of the star in the Yale Bright Star Catalogue is HR7747.
• HIP100027 is the reference name for the star in the Hipparcos Star Catalogue.
• The Id of the star in the Henry Draper catalogue is HD192876. The catalogue was started by the American doctor and has been expanded on over the years.
• The star is catalogued in the Tycho-2 star catalogue as TYC-5748-2598-1. The catalogue lists 2 millions stars and its homepage is E.S.A.
• Flamsteed designations such as 5 Capricorni (5 Cap) are named after the creator, Sir John Flamsteed. Sir John named the stars in the constellation with a number and its latin name, this star's Flamsteed designation is 5 Capricorni. The Flamsteed name can be shortened to 5 Cap.
• 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-12 5683.

Algiedi Prima Travel Time

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.

Mach 1 is the speed of sound, Mach 2 is twice the speed of sound. Corncorde before it was retired was the fastest commercial airline across the Atlantic and only one that could do Mach 2.

Meteor Showers Radiating Near Algiedi Prima

The Alpha Capricornids Meteor Shower radiants from a point near this star. The meteor shower runs typically between Jul 03 - Aug 15 with a peak date of 30th Jul.. The speed of a meteor in the shower is 23 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 23.

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.