GSFC: Fermi Detects Gamma Rays from Nova Cygni 2010

[bystander]

Fermi Detects 'Shocking' Surprise from Supernova's Little Cousin
NASA GSFC Fermi | 11 Aug 2010

Fermi's Large Area Telescope (LAT) saw no sign of a nova in the 19 days prior to March 10 (left), but the eruption is obvious in the following 19 days (right). (Credit: NASA/DOE/Fermi LAT Collaboration)

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Astronomers using NASA's Fermi Gamma-ray Space Telescope have detected gamma-rays from a nova for the first time, a finding that stunned observers and theorists alike. The discovery overturns the notion that novae explosions lack the power to emit such high-energy radiation.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion.

"In human terms, this was an immensely powerful eruption, equivalent to about 1,000 times the energy emitted by the sun every year," said Elizabeth Hays, a Fermi deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "But compared to other cosmic events Fermi sees, it was quite modest. We're amazed that Fermi detected it so strongly."

[bystander]

Fermi Detects Gamma Rays from Exploding Nova
Naval Research Laboratory | PR 89-10r | 23 Aug 2010

Using the Large Area Telescope (LAT) onboard NASA's Fermi Gamma-ray Space Telescope satellite, astronomers have detected gamma rays from a nova for the first time, a finding that surprises both observers and theorists. The discovery dispels the long-held idea that nova explosions are not powerful enough to produce such high-energy radiation. These findings are published in the August 13th edition of Science with Teddy Cheung, an astrophysicist at the Naval Research Laboratory, as the lead author.

A nova is a sudden, rapid increase in the brightness of a star. The explosion occurs when a white dwarf ignites in an enormous thermonuclear explosion. The newly detected explosion is equivalent to about 1,000 times the energy that the sun gives off every year. However, compared to what Fermi is capable of detecting, this exploding nova is a relatively modest event.

Gamma rays are the most energetic form of light, and scientists believe the observed gamma-ray emission arises as a million-mile-per-hour shock wave races from the site of the explosion. Fermi's LAT detected the nova for 15 days.

Gamma-Ray Emission Concurrent with the Nova in the Symbiotic Binary V407 Cygni - Fermi-LAT Collaboration

• Science 329 5993 (13 Aug 2010) DOI: 10.1126/science.1192537