Washington DC: Using the NASA/ESA Hubble Space Telescope, an international team of scientists has identified nine monster stars, which are bigger and brighter than our Sun.
The team led by University of Sheffield combined images taken with the Wide Field Camera 3 (WFC3) with the unprecedented ultraviolet spatial resolution of the Space Telescope Imaging Spectrograph (STIS) to successfully dissect the young star cluster R136 in the ultraviolet for the first time.
R136, which is only a few light-years across and is located in the Tarantula Nebula within the Large Magellanic Cloud, about 170 000 light-years away, hosts many extremely massive, hot and luminous stars.
As well as finding dozens of stars exceeding 50 solar masses, this new study was able to reveal a total number of nine very massive stars in the cluster, all more than 100 times more massive as the Sun. However, the current record holder R136a1 does keep its place as the most massive star known in the Universe, at over 250 solar masses. The detected stars are not only extremely massive, but also extremely bright. Together these nine stars outshine the Sun by a factor of 30 million.
Lead author Paul Crowther said identifying individual stars in this crowded region of space was only possible because of Hubble and he praised the work done by astronauts who risked their lives in 2009 to repair the STIS.
In 2010 Crowther and his collaborators showed the existence of four stars within R136, each with over 150 times the mass of the Sun. At that time the extreme properties of these stars came as a surprise as they exceeded the upper-mass limit for stars that was generally accepted at that time. Now, this new census has shown that there are five more stars with more than 100 solar masses in R136. The results gathered from R136 and from other clusters also raise many new questions about the formation of massive stars as the origin of these behemoths remains unclear.