V1059 Sagittarii (also called Nova Sagittarii 1898) 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 ...

, which lit up in 1898 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 ...

Sagittarius. The star reached

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

4.5, making it easily visible to the naked eye. It was discovered on 8 March 1898, by

Williamina Fleming (15 May 1857 – 21 May 1911) was a Scottish-American astronomer. She was a single mother, hired by the director of the Harvard College Observatory to help in the photographic classification of stellar spectra. She helped develop a common d ...

on a

photographic plate Photographic plates preceded photographic film as a capture medium in photography, and were still used in some communities up until the late 20th century. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinn ...

taken at the

Harvard College Observatory The Harvard College Observatory (HCO) is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, United St ...

. The discovery plate was an

objective prism Slitless spectroscopy is astronomical spectroscopy done without a small slit to allow only light from a small region to be diffracted. It works best in sparsely populated fields, as it spreads each point source out into its spectrum, and crowded f ...

plate, part of the Henry Draper Memorial Photographs, and Ms Fleming identified it as a nova based on its spectral characteristics. The astronomical literature contains a variety of values for V1059 Sagittarii's peak brightness. Özdönmez ''et al.'' list the peak magnitude as 2.0 (

visual The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (the ...

), while Downes ''et al.'' report a much fainter value of magnitude 4.9 (

photographic Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed i ...

). Novae are usually classified as "fast" or "slow" based on the time it takes the star to drop from peak brightness by more than 3 magnitudes (T3), but for this nova the decline from maximum was poorly observed, and no T3 value has been reported. Nonetheless, it is classified as a fast nova. Vogt ''et al.'' monitored the quiescent nova 116 years after the nova event, and saw minor (0.5 to 0.8 magnitude) variations occurring at irregular intervals, similar to low amplitude

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 ...

outbursts. All novae are binary stars, with a "donor" star orbiting 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 ...

. The two stars are so close to each other that matter is transferred from the donor to the white dwarf. In the case of V1059 Sagittarii, pair's orbital period is 6.866±0.017 hours.

References

External links

* Novae Sagittarius (constellation) 1898 in science Sagittarii, V1059 176654 J19015056-1309420 {{var-star-stub