Experts at the Sydney Institute of Astronomy at the University of Sydney (Australia) have discovered a massive “graveyard” of dead stars. Their “remains” have been ejected from the Milky Way and currently exist as neutron stars or black holes.
Neutron stars and black holes are formed when large stars—at least 8 times the size of our Sun—exhaust their fuel and suddenly collapse.
The research team estimates that this “graveyard” of dead stars is about three times larger than the Milky Way itself. This challenges what scientists know about our galaxy.
“Graveyard” of dead stars in the Milky Way – (Photo: PHYS.ORG)
This study was published by the Royal Astronomical Society of Australia.
The Milky Way is the name of a spiral galaxy that contains our Solar System, with an estimated 100 to 400 billion stars.
Finding this special “graveyard” was not an easy task. Over millions of years since these ancient stars were born and died, the galaxy has transformed and is now sparkling with new stars.
The research team had to consider movement dynamics, such as the force from a supernova explosion of a dying star, to predict where the “remains” of the stars would land.
The study found that nearly one-third of the dead stars following a supernova explosion were pushed far away from the boundaries of the Milky Way and have rearranged themselves in an area akin to a “graveyard” dedicated to them.
The fact that dead stars are “ejected” from their galactic home serves as a reminder that supernova “explosions”—traveling at speeds of up to millions of kilometers per hour—are more powerful than scientists previously thought.
Dr. Hirai from the Sydney Institute of Astronomy noted that perhaps the most surprising discovery from this research is that these “explosions” of supernovae are so powerful that the Milky Way may completely lose some remnants of dead stars. “They explode with such force that about 30% of neutron stars are blasted into intergalactic space and never return.”
These strange “remains” are created by the supernova explosion, casting them into the darkness of interstellar space. This goes beyond the current vision and knowledge of astronomers.
The quest to find the hidden “remains” of these ancient stars is described by Professor Tuthill, a member of the research team at the Sydney Institute of Astronomy, as: “It’s like trying to find the graveyard of mythical elephants, referring to a place where, according to legend, old elephants go to die alone, far from their herds.”
Interestingly, active stars can also be displaced from their galaxies.
In 2006, experts from Harvard University discovered a pair of stars racing away from the Milky Way at speeds exceeding 1.6 million kilometers per hour.
Even more fascinating, a direct view shows that the “underground” of the galaxy is “inflated” much more than the Milky Way—resulting from the momentum pumped in by supernovae, lifting them into a visible halo around the Milky Way.
