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Meridiana, Alpha Coronae Australis, HD178253, HIP94114, HR7254

Meridiana Location in Corona Australis

Primary Facts on Meridiana

  • Meridiana's star type is main sequence dwarf star that can be located in the constellation of Corona Australis. The description is based on the spectral class.
  • Meridiana is a main star of the constellation outline.
  • Based on the spectral type (A0/A1V) of the star, the star's colour is blue .
  • Alpha Coronae Australis is the Bayer name for the star. It was assigned this name by Johann Bayer in 1603. The closer to the start of the Greek Alphabet the name, the brighter the star is. Alpha stars tend to be the brightest in the constellation. A notable exception is Pollux (Beta Geminorum) which is the brighest star in the Gemini constellation.
  • The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 125.35 light years away from us.

Meridiana's Alternative Names

Alpha Coronae Australis (Alf Cra) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR7254. HIP94114 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD178253.

Meridiana has alternative name(s) :- Alphecca Meridiana.

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

Location of Meridiana

The location of the 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 star is compared to the celestial equator and is expressed in degrees. For Meridiana, the location is 19h 09m 28.28 and -37° 54` 15.3 .

Radial Velocity and Proper Motion of Meridiana

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 -95.99 ± 0.14 miliarcseconds/year towards the north and 84.87 ± 0.25 miliarcseconds/year east if we saw them in the horizon.

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -18.40 km/s with an error of about 1.78 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.

Meridiana 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 30.49 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) of Meridiana

Meridiana has a spectral type of A0/A1V. This means the star is a blue main sequence dwarf star. The star is 7,364.00 Parsecs from the Galactic Centre or in terms of Light Years is 24,018.67 s. The star has a B-V Colour Index of 0.04 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,025 Kelvin.

Meridiana Radius has been calculated as being 2.29 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,593,978.69.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 2.21. 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 0.26 with an error value of 9.99 Fe/H with the Sun has a value of 1 to put it into context.

Meridiana Apparent and Absolute Magnitudes

Meridiana has an apparent magnitude of 4.11 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 1.11 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.19. 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 Meridiana

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 25.15 which gave the calculated distance to Meridiana as 129.69 light years away from Earth or 39.76 parsecs. It would take a spaceship travelling at the speed of light, 129.69 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 26.02 which put Meridiana at a distance of 125.35 light years or 38.43 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 7,926,701.27 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 7,364.00 Parsecs or 24,018.67 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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 Meridiana Facts and Figures

Visual Facts

Primary / Proper / Traditional NameMeridiana
Alternative NamesAlpha Coronae Australis, Alf Cra, Alphecca Meridiana, HD 178253, HIP 94114, HR 7254
Spectral TypeA0/A1V
Constellation's Main StarYes
Multiple Star SystemNo / Unknown
Star Type main sequence Dwarf Star
Colour blue
GalaxyMilky Way
ConstellationCorona Australis
Absolute Magnitude 1.11 / 1.19
Visual / Apparent Magnitude4.11
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)19h 09m 28.28
Declination (Dec.)-37° 54` 15.3
Galactic Latitude-19.59 degrees
Galactic Longitude359.54 degrees
1997 Distance from Earth25.15 Parallax (milliarcseconds)
 129.69 Light Years
 39.76 Parsecs
2007 Distance from Earth26.02 Parallax (milliarcseconds)
 125.35 Light Years
 38.43 Parsecs
 7,926,701.27 Astronomical Units
Galacto-Centric Distance24,018.67 Light Years / 7,364.00 Parsecs
Proper Motion Dec.-95.99 ± 0.14 milliarcseconds/year
Proper Motion RA.84.87 ± 0.25 milliarcseconds/year
B-V Index0.04
Radial Velocity-18.40 ± 1.78 km/s
Iron Abundance0.26 ± 9.99 Fe/H
Semi-Major Axis7593.00
Stellar Luminosity (Lsun)30.49

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Facts

Calculated Effective Temperature9,025 Kelvin

Sources and Links

SIMBAD SourceLink

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