Hyper-Velocity Stars Are Escaping Their Home Galaxies

Excited for the August 21 eclipse? Visit our Eclipse 2017 page to explore the science, history, and myths of the event. The Curiosity team will be viewing the eclipse alongside NASA in Carbondale, Illinois. Follow us on Facebook for live videos, trivia, and interviews on the big day.

Hypervelocity stars can travel through space fast enough to overcome the escape velocity of their home galaxies, hence the term "unbound." (Some of the rogue stars in our galaxy may have originated in the Magellanic Cloud!) US 708, the fastest known unbound star in the Milky Way, is heading toward intergalactic space at a blistering 2.6 million miles per hour (4.2 million kilometers per hour). It's a hot subdwarf star that consists mostly of helium, but astronomers speculate that it may have started out as a red giant.

Share the knowledge!

Key Facts In This Video

  1. The star US 708 is moving at 745 miles per second (1,200 km/sec) toward intergalactic space. 00:25

  2. US 708 may have originally been a red giant in a binary system with a white dwarf. 02:50

  3. Astronomers analyze Type 1A supernovae to calculate how far away other galaxies are, and how fast they're moving. 03:49

If you liked this you'll love our podcast! Check it out on iTunes, Stitcher, Google Play Music, SoundCloud, search 'curiosity' on your favorite podcast app or add the RSS Feed URL.