Have you ever heard of runaway stars? Sounds funny and bizarre right! But it’s true, there are such stars which are called Runaway stars. Now if you are wondering what are they and why are they named so, you will find the answers in the following paragraphs.
The stars that are moving faster than the expected speed or in a direction that seems unusual relative to the surrounding interstellar medium are called runaway stars. For many years these observations have puzzled astronomers. Among the thousands of very young, heavy, and hot stars that have been observed in our Milky Way galaxy, there exist some runaway stars among them that move with exceptionally high velocities. The motion of such stars may be above 100 km/sec or ten times more than normal and it often points exactly away from a stellar association.
Their existence could be the result of
- Collision or encounters between stellar systems that disrupted both systems where some stars are accelerated to high velocities or even ejected at relatively high speeds.
- A supernova explosion in a multiple star system that accelerated the associated stars which didn’t explode along a new path.
- Gravitational interactions between stars in a stable star system that resulted in large accelerations of one or more associated stars.
Some of the runaway stars that are found until now are AE Aurigae, 53 Arietis, Delta Columbae, etc. The first runaway yellow supergiant star was discovered in the Small Magellanic Cloud- a small satellite galaxy of our Milky Way. It was discovered by astronomers at Lowell Observatory in Flagstaff, Arizona on March 27, 2018. This star is speeding across its little galaxy at about 482,800 km/hour and it is believed to have been in a multiple-star system.
Another such star was found in Tarantula Nebula which is a very large star-forming region than any other nearby galaxies including the Milky Way galaxy. In the heart of this nebula, there are a few clusters where astronomers have found lots of very massive stars. A Runaway star called ‘30 Dor 016’ is believed to have its origin in one of these clusters. From different observations, it was found that this star was about 90 times the mass of the Sun and was moving with a velocity greater than 250,000 miles per hour. It is located about 400 light-years away from the cluster. Based on these observations astronomers have found a few more stars of similar behaviour in that region.
Check out our article: “The Evolution of Stars“
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