V1974 Cygni orNova Cygni 1992 was anova, visible to the naked eye, in theconstellationCygnus.It was discovered visually with 10×50 binoculars on February 19, 1992, byPeter Collins, an amateur astronomer living inBoulder, Colorado. At that time he first noticed it, it had anapparent 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.[6][7] The nova reached magnitude 4.4 at 22:00 UT on 22 February 1992. Images from thePalomar Sky Survey taken before the nova event showed a possible precursor which hadphotographic magnitudes of 18 (blue light) and 17 (red light), but the identification of the precursor is not firm.[8][9]
V1974 Cygni declined from peak brightness by three magnitudes in 43 days, making it a "fast" nova.[10] Its light curve is classified as type P (Plateau), and it may be arecurrent nova.[11]
In 1995, V1974 Cygni was observed with theVery Large Array at 1.49, 4.9, 8.4, 14.9 and 22.5 GHz.[12] It was also studied with theHubble Space Telescope instrument theHigh Speed Photometer.[13] The instrument recorded a short amount of ultraviolet photometry.[13] The nova was also observed in the far-ultraviolet byVoyager 2.[14]It was observed, but not detected, with theCompton Gamma Ray Observatory.[15]It was the first nova to be observed throughout the electromagnetic spectrum, from radio waves toγ-rays.[16]
The location of V1974 Cygni (circled in red)
All novae are binary stars, with a "donor" star orbiting awhite 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 aneon nova.[9] Estimates of the mass of the white dwarf range from 0.98M☉ to 1.12M☉, and it is estimated to be acquiring3.2 × 10−10M☉ yr−1 of material from the donor star.[17]
V1974 Cygni has anova remnant shell which has been observed several times with theHubble Space Telescope, as well as with theInfrared 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.[16] The remnant was also imaged in 6 cm radio waves with theMERLIN interferometer.[12]
^abCutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003)."VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)".CDS/ADC Collection of Electronic Catalogues.2246: II/246.Bibcode:2003yCat.2246....0C.
