Spitzer Image: Supernova Whimpers

While searching the skies for black holes using the Spitzer Space Telescope Deep Wide Field Survey, Ohio State University astronomers discovered a giant supernova that was smothered in its own dust.

In this artists rendering, an outer shell of gas and dust, which erupted from the star hundreds of years ago, obscures the supernova within.


This event in a distant galaxy hints at one possible future for the brightest star system in our own Milky Way.

A giant star in a faraway galaxy recently ended its life with a dust-shrouded whimper instead of the more typical bang.


Ohio State University researchers suspect that this odd event -- the first one of its kind ever viewed by astronomers – was more common early in the universe.

It also hints at what we would see if the brightest star system in our galaxy became a supernova.
In a paper published online in the Astrophysical Journal, Christopher Kochanek, a professor of astronomy at Ohio State, and his colleagues describe how the supernova appeared in late August 2007, as part of the Spitzer Space Telescope Deep Wide Field Survey.

The astronomers were searching the survey data for active galactic nuclei (AGN), super-massive black holes at the centers of galaxies. AGN radiate enormous amounts of heat as material is sucked into the black hole.

In particular, the astronomers were searching for hot spots that varied in temperature, since these could provide evidence of changes in how the material was falling into the black hole.

Normally, astronomers wouldn’t expect to find a supernova this way, explained then-Ohio State postdoctoral researcher Szymon Kozlowski. Supernovae release most of their energy as light, not heat.

But one very hot spot, which appeared in a galaxy some 3 billion  light years from Earth, didn’t match the typical heat signal of an AGN.

The visible spectrum of light emanating from the galaxy didn’t show the presence of an AGN, either – the researchers confirmed that fact using the 10-meter Keck Telescope in Hawaii.

Enormous heat flared from the object for a little over six months, then faded away in early March 2008 – another clue that the object was a supernova.

“Over six months, it released more energy that our sun could produce in its entire lifetime,” Kozlowski said.