source: It contains approximately 150 young, very hot stars that are many times larger and more massive than the Sun. Such stars live for only a few million years before exhausting their hydrogen fuel, due to their extreme luminosity.
target: It contains approximately 150 young, very hot stars. The stars are many times larger and more massive than the Sun.  Such stars live for only a few million years. At their end-of-life they exhaust their hydrogen fuel. The exhaustion occurs due to the stasr' extreme luminosity.
references: It contains approximately 150 young, very hot stars. The stars are many times larger and more massive than the Sun.  Such stars live for only a few million years. At their end-of-life they exhaust their hydrogen fuel. The exhaustion occurs due to the stasr' extreme luminosity.