# NASA Missions Study Shock Waves in Nova Explosion bsfITaEonlU

Unprecedented observations of a nova outburst in 2018 by a trio of satellites, including NASA’s Fermi and NuSTAR space telescopes, have captured the first direct evidence that most of the explosion’s visible light arose from shock waves — abrupt changes of pressure and temperature formed in the explosion debris.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. It occurs when a stream of hydrogen from a companion star flows onto the surface of a white dwarf, a compact stellar cinder not much larger than Earth.

The 2018 outburst originated from a star system later dubbed V906 Carinae, which lies about 13,000 light-years away in the constellation Carina. Over time — perhaps tens of thousands of years for a so-called classical nova like V906 Carinae — the white dwarf’s deepening hydrogen layer reaches critical temperatures and pressures. It then erupts in a runaway reaction that blows off all of the accumulated material.

Fermi detected its first nova in 2010 and has observed 14 to date. Gamma rays the highest-energy form of light require processes that accelerate subatomic particles to extreme energies, which happens in shock waves. When these particles interact with each other and with other matter, they produce gamma rays. Because the gamma rays appear at about the same time as a nova's peak in visible light, astronomers concluded that shock waves play a more fundamental role in the explosion and its aftermath.

The Fermi and BRITE data show…

- Kind: Short
- Year: 2020
- Runtime: 1 min
- By: NASA Goddard
- Genres: Space
- Archive: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:NASA_Missions_Study_Shock_Waves_in_Nova_Explosion_bsfITaEonlU.webm)
- Licence or status: Public domain (as the archive states it)
- Credit: NASA Goddard
- Who can watch: Tweens profiles and older (the archive gives no rating; placed by Invisible Network from its collection and subjects)

[Watch now](https://invisiblenetwork.ai/watch/archive/commons/96296496?play=1)