Nova 2013 Delphini

Nova 2013 Delphinus, discovered by Mr Koichi Itagaki (Teppo-cho, Yamagata, Japan)

on 14th of August 2013 with magnitude 6.8

A nova (plural novae (opens in a new tab) or novas) is a cataclysmic (opens in a new tab) nuclear explosion (opens in a new tab) in a white dwarf (opens in a new tab) star (opens in a new tab). It is caused by the accretion (opens in a new tab) of hydrogen on to the surface of the star, which ignites and starts nuclear fusion (opens in a new tab) in a runaway manner. Novae are not to be confused with supernovae (opens in a new tab) or luminous red novae (opens in a new tab). A nova is a sudden brightening of a star. Novae are thought to occur on the surface of a white dwarf star in a binary system (opens in a new tab). If these two stars are close enough, material from one star can be pulled off the companion star’s surface and onto the white dwarf.

Subtypes

Novae are classified according to the light curve development speed, thus in

NA: Fast novae, with a rapid brightness increase, followed by a brightness decline of 3 magnitudes — to about 1⁄16 brightness — within 100 days.

NB: Slow novae, with a 3 magnitudes decline in 150 days or more.

NC: Very slow novae, staying at maximum light for a decade or more, fading very slowly. It is possible that NC type novae are objects differing physically very much from normal novae, for example planetary nebulae (opens in a new tab) in formation, exhibiting Wolf-Rayet star (opens in a new tab) like features.

NR/RN: Recurrent novae, novae with two or more outbursts separated by 10–80 years have been observed