Nova

A nova is a cataclysmic variable star. It represents a sudden, dramatic brightening of a star, typically a white dwarf in a binary system. This brightening can increase a star's luminosity by factors of thousands to millions, making it appear as a 'new' star in the night sky.

The event is caused by a thermonuclear explosion on the surface of the white dwarf, triggered by the accretion of matter (usually hydrogen) from a companion star.

While the star brightens dramatically, it is not a complete destruction of the star, and the process can repeat over time, meaning a nova isn't necessarily a one-time event.

Nova meaning with examples

• The amateur astronomer excitedly pointed through their telescope, exclaiming, "Look! A nova!" The sudden increase in brightness was undeniable, showcasing a previously unseen star in the constellation of Cygnus. They quickly documented the event, eager to follow the fading luminosity in the coming days.
• Astronomers dedicated many observing hours searching for the faintest signs of a pre-nova star, predicting it would explode. Then one night their anticipation was rewarded when the telescopes detected an unusual spectral signature. A sudden, brilliant light, and the birth of a new nova was immediately confirmed.
• The Hubble Space Telescope captured stunning images of the expanding shell of gas ejected by a previous nova. This visual evidence confirmed that the white dwarf had indeed undergone a thermonuclear flash, leaving behind a beautiful, expanding cloud of stellar debris.
• Scientists developed sophisticated models to understand the complex physics of a nova. By simulating the accretion process and the resulting thermonuclear runaway, they aimed to predict the frequency and characteristics of these dramatic stellar events and study their properties.