Bright Star Shines Light on Mysterious X-ray Sources: A Q&A with MKI’s Deepto Chakrabarty

The Kavli Foundation, Tuesday, October 14, 2014

A newly discovered pulsar, the brightest ever discovered, raises questions about a mysterious category of cosmic objects called ultraluminous X-ray sources. Researcher Deepto Chakrabarty discusses the discovery and how to go about aligning our understanding of the universe with this new revelation.

A team of astronomers including Deepto Chakrabarty of the MIT Kavli Institute announced last week that they have discovered a pulsating star that appears to shine with the energy of 10 million suns. That makes it the brightest pulsar – a type of rotating neutron star that emits a bright beam of energy that regularly sweeps past Earth like a lighthouse beam – ever seen.

The pulsar is so bright that it’s classified as an “ultraluminous X-ray source,” a category of celestial object that’s too bright to be explained by any known process of stellar radiation.

The discovery, published in the journal Nature and made possible by observations with the Nuclear Spectroscopic Telescope Array (NuSTAR), raises even more questions about ultraluminous X-ray (ULX) sources. For example, pulsars are by nature not very massive objects and so have always been assumed only capable of relatively moderate X-ray signals. The fact that the newly discovered pulsar both doesn’t match that understanding and falls into the enigmatic ULX category only adds to the mystery.

The Kavli Foundation asked Chakrabarty, head of the astrophysics division at MIT and a member of the MIT Kavli Institute, what the discovery could mean for our understanding of the ultraluminous universe.  Read the Q&A here.