Astronomers have for the first time seen the birth of a magnetar—a highly magnetized, spinning neutron star—and confirmed that it’s the power source behind some of the brightest exploding stars in the cosmos. The finding corroborates a theory proposed by a UC Berkeley physicist 16 years ago and establishes a new phenomenon in exploding stars: supernovae with a “chirp” in their light curve that is caused by general relativity. A paper describing the phenomenon was published in the journal Nature.
Superluminous supernovae—which can be 10 or more times brighter than run-of-the-mill supernovae—have puzzled astronomers since their discovery in the early 2000s. They were thought to result from the explosion of very massive stars, perhaps 25 times the mass of our sun, but they stayed bright much longer than would be expected when a star’s iron core collapses and its outer layers are subsequently blown off.
In 2010, Dan Kasen, now a UC Berkeley theoretical astrophysicist and professor of physics, was the first to propose that a magnetar was powering the long-lasting glow.





