Deanna Csomo McCool | October 17, 2017
Third-year physics graduate students Kaitlin Rasmussen and Devin Whitten were settling into their observation work in August on the 2.5-meter Irénée du Pont Telescope atop a rocky mountain in Las Campanas, Chile, scouring for a type of star enhanced by a set of reactions called the rapid-neutron capture process, or r-process.
What the two University of Notre Dame students—both advised by astrophysics professor Timothy Beers, Notre Dame Chair in Astrophysics—witnessed instead was perhaps one of the most significant discoveries so far in the field of astrophysics. A stroke of luck for them, a brief flash of gamma rays had been detected 143 million light years away in galaxy NGC 4993, located in the constellation Hydra. And accompanying the bright burst were gravitational waves detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO). All data pointed to a never-before seen event: the merger of two neutron stars.
The event was announced in a series of papers first published online Oct. 16 in Science. Neutron star mergers have proven to be responsible, either in whole or in part, for the formation of nearly half the metals heavier than iron in our solar system. These include gold, platinum, and uranium.
“It was pretty amazing,” Whitten said about being present at the observatory in Chile during the discovery. Rasmussen said she immediately called her mom out of sheer excitement. “Calls are pretty expensive from Chile though, so I sent some texts,” Whitten joked.