The following is a list of all

nova A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...

e that are known to have occurred in 2019. A nova is an energetic astronomical event caused by a

white dwarf A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

accreting matter from a star it is orbiting (typically a

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

, whose outer layers are more weakly attached than smaller, denser stars) Alternatively, novae can be caused by a pair of stars merging with each other, however such events are vastly less common than novae caused by white dwarfs. In 2019, at least sixteen Milky Way novae were discovered, eight of which were

dwarf nova A U Geminorum-type variable star, or dwarf nova (pl. novae) is one of several types of cataclysmic variable star, consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from its companion. Dw ...

eruptions, one of the variable system V386 Serpentis, one from the known nova-like system 2E 1516.6-6827, and four from previously unidentified white dwarf binaries. One of these binaries, TCP J18200437-1033071, may have possibly been involved in another outburst in 1951. The recurrent nova V3890 Sgr, which had been seen to erupt in 1962 and 1990, also erupted again in 2019.

List of novae in 2019

In the Milky Way

In the Andromeda Galaxy

Novae are also frequently spotted in the Andromeda Galaxy, and are even slightly more commonly found than in the Milky Way, as there is less intervening dust to prevent their detection. Furthermore, Andromeda is circumpolar for observers north of latitude +48-50, roughly the latitude of the Canadian-American border, allowing observers north of that to search for transients all year. In 2019, 11 novae have been seen in the Andromeda galaxy.

In other galaxies

Any galaxy within 20 million light-years of the Sun could theoretically have nova events bright enough to be detected from Earth, although in practice most are only detected in galaxies within 10-15 million light-years of the Milky Way, such as the

Triangulum Galaxy The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC (''New General Catalogue)'' 598. With the D25 isophotal diameter of , the Triangulum Galax ...

Messier 81 Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major. It has a D25 isophotal diameter of . Because of its relative proximity to the Milky Way ga ...

, Messier 82, Messier 83, and Messier 94. In 2019, two novae were observed in Messier 81, and another in the Triangulum Galaxy. A luminous red nova was observed in the Whirlpool Galaxy (Messier 51a), probably caused by a merger of two stars.

Notes

References

External links

List of all galactic novae
{{2019 in space 2019 in space Novae Novae in 2019

Novae A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...