R136a1 is a wolf-rayet star that is not located in our galaxy but is in the NGC 2070 open cluster in the Tarantula Nebula. The star can not be seen by the naked eye, you need a telescope to see it.
R136a1 with its catchy easy to roll off the tongue name is one of the massive stars in the universe. I say universe because it is not in the the milky way. The star is situated within the Tarantula nebula, a massive globular star cluster. The Tarantula Nebula is not in the Milky Way but in a satellitegalaxy known as the Large Magellanic Cloud.
The current largest widely recognised star in the universe is UY Scuti. R136a1 is the most massive, defined by having the biggest mass of all the stars so far looked at. There could be a bigger more massive star out there but we've not discovered it, it could be in a galaxy far far away (sounds like stars wars doesn't it.). The star is believed to have grown to such a size by merging with other stars, cannibalised them in other words.
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 R136a1, the location is 05h 38m 42.43 and -69 ° 06` 02.2 .
R136a1 has a spectral type of WN5h. R136a1 lies at a distance of 163,000.00 light years away from our Sun and our planet Earth or to put it another way, 49,974.96 parsecs away from the Sun. The star has a B-V Colour Index of 1 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,973 Kelvin.
R136a1 has been calculated as 28.80 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 20,039,040.00.km. If you need the diameter of the star, you just need to multiple the radius by 2.
R136a1 has an apparent magnitude of 12.23 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual 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.
R136a1 is an estimated 163,000.00 light years from our Solar System (Earth and Sun). It would take a spaceship 163,000.00 years travelling at the speed of light to get there. We don't have a space ship that can travel that distance or at that speed yet.
|Primary / Proper / Traditional Name||R136a1, Most Massive Star in the Universe|
|Multiple Star System||No / Unknown|
|Star Type||Wolf-Rayet star|
|Galaxy||Tarantula Nebula (NGC2070)|
|Visual / Apparent Magnitude||12.23|
|Naked Eye Visible||Requires a 4.5 - 6 Inch Telescope - Magnitudes|
|Right Ascension (R.A.)||05h 38m 42.43|
|Declination (Dec.)||-69 ° 06` 02.2|
|Distance from the Sun / Earth||163,000.00 Light Years|
|Radius (x the Sun)||28.80|