nova

A star that suddenly increases in luminosity and then gradually returns to its original brightness over a period of weeks to years.

A ‘new’ or temporary star; a star which makes its appearance suddenly and gradually fades away, the whole decline generally occupying some years and leaving the star still visible in large telescopes. About twenty such stars have thus far been recorded.

A star which suddenly increases in brightness thousands of times, then fades back to near its original intensity. It may appear as a “new” star if its original brightness was too low for routine observation. A star which suddenly increases in brightness to many millions of times its original intensity is a supernova, and the postulated mechanisms for the increases of brightness of novae and supernovae are different.

Any sudden brightening of a previously inconspicuous star.

a star that ejects some of its material in the form of a cloud and become more luminous in the process