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Nu2 Arae - HD161917 - HIP87379

Nu2 Arae is a blue subgiant star that can be located in the constellation of Ara. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Nu2 Arae is the Bayer Classification for the star. HIP87379 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD161917.

Location of Nu2 Arae

The location of the star in the galaxy 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 Nu2 Arae, the location is 17h 51m 11.03 and -53d07`49.0 .

Proper Motion of Nu2 Arae

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 0.08 ± 0.24 miliarcseconds/year towards the north and 15.79 ± 0.43 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Nu2 Arae

Nu2 Arae has a spectral type of B9.5III/IV. This means the star is a blue subgiant star. The star is 7259.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23676.1971409600000000s. The star has a B-V Colour Index of 0.01 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 9,392 Kelvin.

Nu2 Arae Radius has been calculated as being 3.32 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,311,374.86.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 3.34. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Nu2 Arae Apparent and Absolute Magnitudes

Nu2 Arae has an apparent magnitude of 6.09 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 0.13 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.12. 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 Nu2 Arae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.42 which gave the calculated distance to Nu2 Arae as 508.04 light years away from Earth or 155.76 parsecs. It would take a spaceship travelling at the speed of light, 508.04 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 6.41 which put Nu2 Arae at a distance of 508.84 light years or 156.01 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.

The star's Galacto-Centric Distance is 7,259.00 Parsecs or 23,676.20 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.

Nu2 Arae Facts

Alternative Names

Bayer DesignationNu2 Arae
Hipparcos Library I.D.87379
Henry Draper Designation161917

Visual Facts

Star Typesubgiant star
Absolute Magnitude0.13 / 0.12
Visual / Apparent Magnitude6.09
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)17h 51m 11.03
Declination (Dec.)-53d07`49.0
Galactic Latitude-13.06 degrees
Galactic Longitude339.43 degrees
1997 Distance from Earth6.42 Parallax (milliarcseconds)
 508.04 Light Years
 155.76 Parsecs
2007 Revised Distance from Earth6.41 Parallax (milliarcseconds)
 508.84 Light Years
 156.01 Parsecs
Galacto-Centric Distance23,676.20 Light Years / 7,259.00 Parsecs
Proper Motion Dec.0.08 ± 0.24 milliarcseconds/year
Proper Motion RA.15.79 ± 0.43 milliarcseconds/year
B-V Index0.01
Radial Velocity18.80 ± 1.20 km/s
Spectral TypeB9.5III/IV
Colour(B) blue

Estimated Facts

Calculated Effective Temperature9,392 Kelvin

Sources and Links

SIMBAD SourceLink

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