V849 Ophiuchi or Nova Ophiuchi 1919 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 ...

that erupted in 1919, 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 ...

Ophiuchus, and reached a

blue band The Pennsylvania State University Marching Blue Band, known generally as the Blue Band, is the marching band of Pennsylvania State University. Founded in 1899, it is the largest recognized student organization at the University Park campus o ...

brightness of magnitude 7.2. Joanna C. S. Mackie discovered the star while she was examining Harvard College Observatory

photographic plates 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 ...

. The earliest plate it was visible on was exposed on August 20, 1919, when the star was at magnitude 9.4. It reached magnitude 7.5 on September 13 of that year. In its quiescent state it has a visual magnitude of about 18.8. V849 Ophiuchi is classified as a "slow nova"; it took six months for it to fade by three magnitudes. All novae are

binary star A binary star 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 using a telescope as separate stars, in wh ...

s, and V849 is an eclipsing binary. Its orbital period is 4.146128 hours.

References

External links

*https://web.archive.org/web/20050909054008/http://www.tsm.toyama.toyama.jp/curators/aroom/var/nova/1910.htm Novae Ophiuchus ? Ophiuchi, V849 167276 {{Var-star-stub