V603 Aquilae (or Nova Aquilae 1918) was a bright nova first observed (from Earth) in the constellation Aquila in 1918. It is a binary system, comprising a white dwarf and donor low-mass star in close orbit to the point of being only semidetached. The white dwarf sucks matter off its companion, which has filled its Roche lobe, onto its accretion disk and surface until the excess material is blown off in a thermonuclear event. This material then forms an expanding shell, which eventually thins out and disappears.
Epoch J2000 Equinox J2000
|Right ascension||18h 48m 54.6366s|
|Declination||+00° 35′ 02.863″|
|Apparent magnitude (V)||11.64|
|B−V color index||-0.2 ± 0.5|
|Variable type||Variable star|
|Radial velocity (Rv)||−23 km/s|
|Proper motion (μ)|| RA: 10.81 mas/yr |
Dec.: −8.86 mas/yr
|Absolute magnitude (MV)||11.65|
Nova Aql 1918, Nova Aquilae 1918, EM* CDS 1028, HD 174107, 1RXS J184854.7+003501, ALS 9992, 1ES 1846+00.5, SBC7 706, AN 7.1918, FASTT 1189, HIP 92316, UBV M 51004, CSI+00-18463, GCRV 68659, KPD 1846+0031, 2E 1846.3+0031, LS IV +00 3, 2E 4138, GSC 00448-00423, 2MASS J18485464+0035030, EM* RJHA 116, HBHA 202-05, PLX 4341, AAVSO 1843+00.
First seen by Zygmunt Laskowski, a medical professor and amateur astronomer, and then confirmed on the night of 8 June 1918 by the UK amateur astronomer Grace Cook, The nova is estimated at between 784 to 839 light years distance from Earth . Nova Aquilae reached a peak magnitude of −0.5; it was the brightest nova recorded in the era of the telescope. It was brighter than all stars but Sirius and Canopus. Tycho's and Kepler's supernovae were brighter, but both occurred before the invention of the telescope. Originally a star system with a magnitude of 11.43, it took twelve days to fade three magnitudes and then 18.6 years to fade to quiescence. In 1964 Robert P. Kraft ascertained that it was a binary system, recently[when?] determined to be true for several other novae at the time.
The star system has settled to an average apparent magnitude of 11.4 since the 1940s, fading by around 1/100 of a magnitude per decade. Spectroscopic analysis conducted by Arenas and colleagues indicated the system consisted of a white dwarf of about 1.2 times as massive as the sun, with an accretion disk, and a companion star with about 20% of the Sun's mass. This second star is most likely a red dwarf. The two stars orbit each other approximately every 3 hours 20 minutes.
- Harrison, Thomas E.; et al. (2013). "Hubble Space Telescope Fine Guidance Sensor Parallaxes for Four Classical Novae". The Astrophysical Journal. 767 (1). 7. arXiv:1302.3245. Bibcode:2013ApJ...767....7H. doi:10.1088/0004-637X/767/1/7. S2CID 118376206.
- Selvelli, P. L.; Cassatella, A. (1981). "Nova AQL 1918 - A nude old nova". In: Effects of Mass Loss on Stellar Evolution; Proceedings of the Fifty-ninth Colloquium, Trieste, Italy, September 15–19, 1980. (A82-33926 16-90) Dordrecht, D. Reidel Publishing Co. Astrophysics and Space Science Library. 89: 515–522. Bibcode:1981ASSL...89..515S. doi:10.1007/978-94-009-8500-1_74. ISBN 978-94-009-8502-5.
- Johnson, Christopher B.; Schaefer, Bradley E.; Kroll , Peter; Henden, Arne A. (2013). "Nova Aquilae 1918 (V603 Aql) Faded by 0.44 mag/century from 1938-2013". The Astrophysical Journal. 780 (2): L25. arXiv:1310.6802. Bibcode:2014ApJ...780L..25J. doi:10.1088/2041-8205/780/2/L25. S2CID 118403602.
- The Contribution of Amateurs to Astronomy, Proceedings of Colloquium 98 of the International Astronomical Union, June 20–24, 1987, page 41
- Mobberley, Martin (2009). Cataclysmic Cosmic Events and How to Observe Them. Springer. p. 46. ISBN 978-0-387-79946-9.
- Moore, Patrick (2006). The Amateur Astronomer. Springer. p. 145. ISBN 978-1-84628-286-7.
- Drechsel, H.; Holm, A.; Krautter, J. & Rahe, J. (1981). "Phase-dependent optical and ultraviolet observations of the old nova V603 Aquilae (1918)". Astronomy & Astrophysics. 99 (1): 166–72. Bibcode:1981A&A....99..166D.
- Kraft, Robert P. (1964). "Binary stars among cataclysmic variables. III. Ten old novae". Astrophysical Journal. 139: 457–75. Bibcode:1964ApJ...139..457K. doi:10.1086/147776.
- Arenas, J.; Catalán, M. S.; Augusteijn, T.; Retter, A. (2000). "A spectroscopic study of V603 Aquilae: stellar parameters and continuum-line variations". Monthly Notices of the Royal Astronomical Society. 311 (1): 135–48. Bibcode:2000MNRAS.311..135A. doi:10.1046/j.1365-8711.2000.03061.x.