Proxima Centauri is the closest star to the Earth after the Sun. It is a small red dwarf and as such, it lay undiscovered in the heavens. It is a faint star, one that is not possible to see with the naked eye.
Red Dwarf stars are the most efficient stars in the Universe, they convert hydrogen into helium at a very slow rate compared to giant stars such as Betelgeuse for example. A red dwarf star will live longer than most other other stars due to the way it uses its fuel reserves. Long after the Sun has died, Proxima Centauri will still be alive, continuing to convert hydrogen into helium.
In addition to be the second closest star at a mere 4 light years away, it is also the nearest star with an extrasolar planet in orbit. The bad news is that the planet is constantly being flamed by its star and therefore you can rule out there being any life on the planet.
(Alpha Centauri C) is the Bayer Classification for the star. HIP70890 is the reference name for the star in the Hipparcos Star Catalogue. The Gliese ID of the star is GL 551. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Star Names
Proxima Centauri has alternative name(s) :- , Proxima Cen.
More details on star alternative names can be found at Star Names .
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 Proxima Centauri, the location is 14h 29m 47.75 and -62° 40` 52.9 .
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 765.54 ± 1.57 miliarcseconds/year towards the north and -3,775.75 ± 2.60 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 -22.40 km/s with an error of about 0.50 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.
Proxima Centauri has a spectral type of M5Ve. This means the star is a red main sequence star. The star is 7,399.00 Parsecs from the Galactic Centre or in terms of Light Years is 24,132.83 s. The star has a B-V Colour Index of 1.8 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 2,942 Kelvin.
Proxima Centauri Radius has been calculated as being 0.03 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 20,227.90.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 0.03. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.
Proxima Centauri has an apparent magnitude of 11.01 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 15.46 If you used the 2007 Parallax value, you would get an absolute magnitude of 15.44. 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.
Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 772.33 which gave the calculated distance to Proxima Centauri as 4.22 light years away from Earth or 1.29 parsecs. It would take a spaceship travelling at the speed of light, 4.22 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 771.64 which put Proxima Centauri at a distance of 4.23 light years or 1.30 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 268,142.38 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 7,399.00 Parsecs or 24,132.83 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.
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.
|Primary / Proper / Traditional Name||Proxima Centauri|
|Alternative Names||Alpha Centauri C, HIP 70890, Gliese 551, Proxima Cen|
|Constellation's Main Star||No|
|Multiple Star System||Yes|
|Star Type||main sequence Dwarf Star|
|Absolute Magnitude||15.46 / 15.44|
|Visual / Apparent Magnitude||11.01|
|Naked Eye Visible||Requires a 4.5 - 6 Inch Telescope - Magnitudes|
|Right Ascension (R.A.)||14h 29m 47.75|
|Declination (Dec.)||-62° 40` 52.9|
|Galactic Latitude||-1.93 degrees|
|Galactic Longitude||313.95 degrees|
|1997 Distance from Earth||772.33 Parallax (milliarcseconds)|
|4.22 Light Years|
|2007 Distance from Earth||771.64 Parallax (milliarcseconds)|
|4.23 Light Years|
|268,142.38 Astronomical Units|
|Galacto-Centric Distance||24,132.83 Light Years / 7,399.00 Parsecs|
|Proper Motion Dec.||765.54 ± 1.57 milliarcseconds/year|
|Proper Motion RA.||-3775.75 ± 2.60 milliarcseconds/year|
|Radial Velocity||-22.40 ± 0.50 km/s|
|Associated / Clustered Stars||Rigil Kentaurus|
|Calculated Effective Temperature||2,942 Kelvin|
|Name||Status||Mass (Jupiters)||Orbital Period (Days)||Eccentricity||Discovered||Semi-Major Axis||Periastron|
|Proxima Cen b||Confirmed||0.0006||11.186||0.0||2016||0.0485|
This is a N.A.S.A. impression of what the solar system might look like. If the star is not on display, its because its so small compared to the orbits of the outer planets. The green area denotes the habital zone which if the planet is within that area, life could exist. The habital zone might not appear on the picture because its outside the area for the picture. Our planets show the orbit of the planet if its was in our solar system. For more information about the planet and other exoplanetary stuff, visit N.A.S.A.
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