Astronomers have discovered the universe’s gold mine in the form of colliding dead stars. Scientists already knew of the extraterrestrial origins of the precious metal, but the discovery sheds light on just how much gold is created by the collision of two neutron stars.
Gold is rare throughout the universe and can be created only as a byproduct of explosions or other catastrophic cosmic events. Led by Edo Berger, from the Harvard-Smithsonian Center for Astrophysics, CfA, a team of researchers observed a collision between two neutron stars, dead stars that previously exploded as supernovae, and the resulting gamma-ray burst, GRB, in June. A neutron star is the remnant of a massive star whose core has collapsed, causing the star to go supernova. The study was published in the Astrophysical Journal Letters.
The astronomers observed a glow from the GRB in the days after the collision that did not match the typical “afterglow” signature of such an event. The glow indicated the creation of heavy elements, such as gold, reports the CfA press release. Despite the GRB lasting just two-tenths of a second, the amount of gold produced from the event is rather impressive. The team estimated the gold produced from the event to weigh up to 10 moon masses, which is “quite a lot of bling,” according to Berger.
A GRB is flash of gamma rays from an explosion and can last between a few milliseconds and several minutes. The GRB in June was considered a short event and the glow being emitted after the collision did not match the typical afterglow caused by particles ejected from the explosion colliding into debris in the surrounding area. According to the CfA release, the researchers believe the glow from the GRB may have been caused by radioactive elements created by ejected neutron particles colliding with the surrounding environment. The glow caused by the elements undergoing radioactive decay could be a definitive signature of a GRB, something that researchers could use in the future to observe such events. Co-author Wen-fai Fong said a statement, “We've been looking for a 'smoking gun' to link a short gamma-ray burst with a neutron star collision. The radioactive glow from GRB 130603B may be that smoking gun.”
By estimating how much gold may have been produced in a single short GRB, the researchers then multiplied that estimate with the number of known short GRBs that have occurred in the history of the universe. According to CfA, based on the calculation, it is possible that all the gold produced in the universe is the result of GRBs.