R136c

R136c is a Wolf–Rayet star of the spectral type WN5h and with a temperature of , making it one of hottest stars known. It is one of the most massive stars known, with a mass of , and it is one of the most luminous stars known, with a luminosity of 3.8 million . The extreme luminosity is produced by the CNO fusion process in its highly compressed hot core. Typical of all Wolf–Rayet stars, R136c has been losing mass by means of a strong stellar wind with speeds over and mass loss rates in excess of solar masses per year. It is strongly suspected to be a binary, due to the detection of hard x-ray emission typical of colliding wind binaries, but the companion is thought to make only a small contribution to the total luminosity. Absorption lines in the spectrum, tentatively assigned to the companion, indicate that it is considerably more massive than the Wolf-Rayet component. An orbit has been derived, but with low confidence and even the period is uncertain, between 5 and 47 days. == Evolution ==

R136c is so energetic that it has already lost a substantial fraction of its initial mass, even though it is only a few million years old. It is still effectively on the main sequence, fusing hydrogen at its core via the CNO cycle, but it has convected and mixed fusion products to the surface and these create a powerful stellar wind and emission spectrum normally only seen in highly evolved stars. ==References==