Intergalactic star

In 2015, a study of supernovae in intergalactic space suggested that the progenitor stars had been expelled from their host galaxies during a galactic collision between two giant ellipticals, as their supermassive black hole centres merged.

[5] In this respect, model calculations (from 1988) predict the supermassive black hole in the center of our Milky Way galaxy to expel one star every 100,000 years on average.

In 2005, at the Smithsonian Center for Astrophysics, Warren Brown and his team attempted to measure the speeds of hypervelocity stars by using the Doppler Technique, by which light is observed for the similar changes that occur in sound when an object is moving away or toward something.

"One of the newfound exiles is moving in the direction of the constellation Ursa Major at about 1.25 million mph with respect to the galaxy.

[9] Some recently discovered supernovae have been confirmed to have exploded hundreds of thousands of light-years from the nearest star or galaxy.

Since then, several other anisotropies at other wavelengths – including blue and x-ray – have been detected with other space telescopes and they are now collectively described as the diffuse extragalactic background radiation.

Several explanations have been discussed by scientists, but in 2012, it was suggested and shown how for the first time this diffuse radiation might originate from intergalactic stars.

The study led by Kelly Holley-Bockelmann and Lauren Palladino from Vanderbilt University highlighted the unusual red coloration and high velocities of these stars, indicating their dramatic journey from the galactic center.