V533 Herculis was 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 ...

visible to the naked eye, which occurred in 1963 in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the Gr ...

. The nova was discovered by the Swedish amateur astronomer Elis Dahlgren on 6 February 1963, and independently by an American amateur,

Leslie Peltier Leslie Copus Peltier (January 2, 1900 – May 10, 1980) was an American amateur astronomer and discoverer of several comets and novae, including Nova Herculis 1963. He was once described as "the world's greatest non-professional astronomer" by ...

, on 7 February 1963. Both reported it to be a 4th

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

star. Subsequent examination of pre-discovery images, taken by the Baker-Nunn satellite tracking group at the Tokyo Observatory, showed that the star had begun its nova event as early as 18:36 UT on 26 January 1963, when it had an magnitude of 8. It had attained its peak brightness, magnitude 3, by 17:38 UT on 30 January 1968. All novae are binary stars, with a "donor" star transferring matter to 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 ...

. In the case of V533 Herculis, the pair's orbital period is 3.43 hours. Thorstensen and Taylor analysed spectra of the star in its quiescent state, and concluded that it is a non-eclipsing SW Sextantis variable, implying that the donor star is a

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

. Knigge derived a mass of 0.225 M_⊙, and a radius of 0.333 R_⊙, for the donor star. V533HerNebulaExpanding

Images of V533 Herculis taken with the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

show a faint, approximately circular shell (

nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...

) with a diameter of 10±1.4 arc seconds, surrounding the star. The shell is expanding at 850±150 km/sec. Santamaria ''et al.'' obtained similar results by comparing images of the shell taken in 1993 and 2018. They found that by 2018 the slightly elliptical shell had major and minor axis of 16.8×15.2 arc seconds, and it was expanding at a rate of 0.152×0.139 arc seconds per year, implying a physical expansion rate of 850×770 km/sec. V533HerLocation

References

External links

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{{DEFAULTSORT:V533 Herculis Novae Hercules (constellation) 1963 in science Herculis, V533