V728 Scorpii, also known as Nova Scorpii 1862, was a

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

that occurred in the constellation of

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation whose recognition pred ...

. It was discovered on 4 October 1862 by

John Tebbutt John Tebbutt (25 May 1834 – 29 November 1916) was an Australian astronomer and meteorologist, famous for discovering the Great Comets of C/1861 J1, 1861 and C/1881 K1, 1881. Early life Tebbutt was born at Windsor, New South Wales, the only son ...

, an astronomer living in

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

, Australia, while observing a comet. He reported that the star was in the constellation

Ara Ara may refer to: Biology * ''Ara'' (bird), a genus of parrots * Ara (fish) (''Niphon spinosus''), a species of fish * L-arabinose operon, also known as ara Places * Ara (mountain), a mountain in Armenia * Ara, Armenia, a village in Armenia ...

. At the time of its discovery, the nova had an

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

of 5, making it visible to the unaided eye. Nine days later, it faded below 11th magnitude, indicating that it was a very fast nova. V728ScoLightCurve

Tappert ''et al.'' conducted an observing program from 2009 to 2011 to investigate nova candidates. Using photometric and

spectroscopic Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectrosc ...

observations, they identified the post-nova star corresponding to Nova Scorpii 1862. On 20 May 2009, the star had a visible-band magnitude of 18.5. They reported that the spectrum resembled that of a

dwarf nova A dwarf nova (pl. wiktionary:nova, novae), or U Geminorum variable, 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 accretion disk, accretes matter ...

with a high orbital inclination, suggesting that it might be an

eclipsing variable A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

. Follow-up observations by the same team found that V728 Scorpii was indeed an eclipsing system. All novae are binary stars, in a very close orbit with a "donor" star transferring material to a

white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...

companion. The eclipses in this system appear to be eclipses of the

accretion disk An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...

surrounding the white dwarf, rather than either star. The orbital period is 3.32 hours.

References

{{Stars of Scorpius Scorpius 1862, Nova Scorpius Scorpii, V728 Eclipsing binaries