A micronova is a type of thermonuclear explosion on the surface of 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 ...

much smaller than the strength of a

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 ...

; being about in strength, about a millionth that of a typical nova. The phenomenon was first described in April 2022.

History

A team led by

Durham University , mottoeng = Her foundations are upon the holy hills (Psalm 87:1) , established = (university status) , type = Public , academic_staff = 1,830 (2020) , administrative_staff = 2,640 (2018/19) , chancellor = Sir Thomas Allen , vice_chan ...

researchers announced on 20 April 2022 that they identified three micronovae using data from the

Transiting Exoplanet Survey Satellite Transiting Exoplanet Survey Satellite (TESS, Explorer 95 or MIDEX-7) is a space telescope for NASA's Explorer program, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the ''Kepler' ...

(TESS). The team discovered with TESS that two of the micronovae occurred on white dwarfs, with the astronomers confirming with the

Very Large Telescope The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, ...

that the third occurred on a white dwarf as well. The phenomenon had previously been observed in the white dwarf binary TV Columbae using data from the International Ultraviolet Explorer. However the data was not sufficient to infer the physical mechanism behind the explosion.

Formation

Micronovae specifically form on white dwarfs that have strong magnetic fields, as fields send material toward the star's magnetic poles. This causes the hydrogen fusion explosions on the surface to be more localized and small than a typical nova.

History

Formation

References

See also