CP Lacertae

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CP Lacertae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lacerta
Right ascension 22h 15m 41.09s[1]
Declination +55° 37′ 01.4″[1]
Apparent magnitude (V) 2.1 Max.
16.6 Min.[2]
Variable type Nova[2]
Distance 1,670±610[3] pc
Other designations
Nova Lac 1936, AAVSO 2212+55
Database references

CP Lacertae (also known as Nova Lacertae 1936 or CP Lac) was a nova, which lit up on June 18, 1936 in the constellation Lacerta. It was discovered independently by several observers including Leslie Peltier in the USA and E. Loreta in Italy. The nova reached a peak brightness of 2.1 mag,[4] making it readily visible to the naked eye during night time. Following the outbreak, the brightness of CP Lacertae decreased thereafter, falling 3 magnitudes after nine days.

Located at an estimated distance of 5.4 ± 2.0 kly (1.67 ± 0.61 kpc),[3] this is a close binary system with a degenerate white dwarf primary in orbit with a cool red dwarf secondary over a period of 0.145143 days.[5] Matter from the red dwarf is being drawn off onto an accretion disk orbiting the white dwarf. The mean brightness of the system varies with an amplitude of 0.5 magnitude from day to day. The observational data shows a general period of 0.037 days, which may be related to the rotation period of the white dwarf component.[6]


  1. ^ a b Cutri, R. M.; et al. (June 2003), "2MASS All Sky Catalog of point sources", The IRSA 2MASS All-Sky Point Source Catalog, NASA/IPAC, Bibcode:2003tmc..book.....C. 
  2. ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S. 
  3. ^ a b Özdönmez, Aykut; et al. (September 2016), "The distances of the Galactic novae", Monthly Notices of the Royal Astronomical Society, 461 (2): 1177−1201, arXiv:1606.01907Freely accessible, Bibcode:2016MNRAS.461.1177O, doi:10.1093/mnras/stw1362. 
  4. ^ Howarth, I. D. (October 1978), "CP Lacertae (Nova 1936)", Journal of the British Astronomical Association, 88: 608−618, Bibcode:1978JBAA...88..608H. 
  5. ^ Pavlenko, E. P.; et al. (May 2007), "The Photometric Study of Nova Lacertae 1936 = CP Lac Between 2003 -- 2005", in Demircan, O.; Selam, S. O.; Albayrak, B., Solar and Stellar Physics Through Eclipses ASP Conference Series, Vol. 370, proceedings of the conference held 27-29 March, 2006 at Ankara University, ÖRSEM Campus, Side, Antalya, Turkey, Astronomical Society of the Pacific, p. 324, Bibcode:2007ASPC..370..324P. 
  6. ^ Litvinchova, A. A.; Pavlenko, E. P. (December 2010), "The Photometric Investigation of the Active Post-Nova CP Lac in High and Low State of Brightness in 2006-2008 yrs", Odessa Astronomical Publications, 23: 76, Bibcode:2010OAP....23...76L.