V1974 Cygni or Nova Cygni 1992 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, 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 ...

Cygnus. It was discovered visually with 10×50 binoculars on February 19, 1992, by Peter Collins, an amateur astronomer living in

Boulder, Colorado Boulder is a home rule city that is the county seat and most populous municipality of Boulder County, Colorado, United States. The city population was 108,250 at the 2020 United States census, making it the 12th most populous city in Color ...

. At that time he first noticed it, it had an apparent magnitude of 7.2. Nine hours later he saw it again, and it had brightened by a full magnitude. For this discovery Collins was awarded the AAVSO Nova Award in 1993. The nova reached magnitude 4.4 at 22:00 UT on 22 February 1992. Images from the Palomar Sky Survey taken before the nova event showed identified a possible precursor which had photographic magnitudes of 18 (blue light) and 17 (red light), but the identification of the precursor is not firm. V1974 Cygni declined from peak brightness by three magnitudes in 43 days, making it a "fast" nova. Its light curve is classified as type P (Plateau), and it may be a recurrent nova. In 1995, V1974 Cygni was observed with the Very Large Array at 1.49, 4.9, 8.4, 14.9 and 22.5 GHz. It was also studied with the Hubble Space Telescope instrument the High Speed Photometer. The instrument recorded a short amount of ultraviolet photometry. The nova was also observed in the far-ultraviolet by Voyager 2. It was observed, but not detected, with the Compton Gamma Ray Observatory. It was the first nova to be observed throughout the electromagnetic spectrum, from radio waves to

γ-rays A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nucleus, atomic nuclei. It consists of the shortest wavelength electromagnetic wav ...

All novae are binary stars, with a "donor" star orbiting a white dwarf. The two stars are so close to each other that matter is transferred from the donor to the white dwarf. In the case of V1974 Cygni, the binary's orbital period is 1 hour, 57 minutes. The nova has an oxygen-neon-magnesium white dwarf primary, making it a

neon 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 ...

. Estimates of the mass of the white dwarf range from 0.98 to 1.12, and it is estimated to be acquiring of material from the donor star. V1974 Cygni has a nova remnant shell which has been observed several times with the Hubble Space Telescope, as well as with the Infrared Space Observatory. The shell is nearly circular, and its radius as of 10 February 1998 was 0.983 arc seconds. It is expanding at a rate of about 0.26 milli arc seconds per day. The remnant was also imaged in 6 cm radio waves with the

MERLIN Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mage, with several other main roles. His usual depiction, based on an amalgamation of historic and le ...

interferometer.

References

External links

* https://web.archive.org/web/20050915104557/http://www.tsm.toyama.toyama.jp/curators/aroom/var/nova/1990.htm * http://www.aavso.org/v1974-cyg-nova-cygni-1992 {{Novae Cygni, V1974 Novae Cygnus (constellation) 1992 in science

See also

References

External links