Runaway Star

Runaway stars are massive stars traveling rapidly through interstellar space. Like a ship plowing through the interstellar medium , runaway star HD 77581 has produced this graceful arcing bow wave or “bow shock” - compressing the gaseous material in its path. Located near the centre of this European Southern Observatory photograph , HD 77581 itself is so bright that it saturates the sensitive camera and produces the spiky cross shape . This star is over 6,000 light-years away in the constellation Vela , and appears to move at over 50 miles per second. What force could set this star in motion? A clue to the answer may lie in its optically invisible companion star, an X-ray bright pulsar known as Vela X-1. This pulsar is clearly the remnant of a supernova explosion ... which seems to have given this massive star and its companion a mighty kick !