RR Pictoris

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RR Pictoris

Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pictor
Right ascension 06h 35m 36.25s
Declination −62° 38′ 22.0″
Apparent magnitude (V) 1.2Max.
Distance 400[1] pc
Absolute magnitude (MV) -6.9[1]
Other designations

RR Pictoris, also known as Nova Pictoris 1925, is a cataclysmic variable star system that flared up as a nova that lit up in the constellation Pictor in 1925. It was first noticed by South African astronomer R. Watson on 25 May 1925 when it had an apparent magnitude of 2.3. It continued to brighten to magnitude 1.2, which it reached on 9 June 1925. It dimmed to magnitude 4 by 4 July, but brightened again to 1.9 on 9 August. Six months after its peak brightness, RR Pictoris faded to be invisible to the unaided eye, and was magnitude 12.5 by 1975.[2]

Novae are close binary systems composed of a white dwarf and secondary star that is so close it is filling up its Roche lobe with stellar material, which is then transferred onto the first star's accretion disc. Once this material reaches a critical mass, it ignites and the system brightens tremendously. The two stars of RR Pictoris orbit each other every 3.48 hours. Calculations of the speed suggest the secondary star is not dense enough for its size to still be on the main sequence, so it itself must have begun expanding and cooling already as its core has run out of hydrogen fuel.[3] The RR Pictoris system is estimated to lie around 400 parsecs (1300 light-years) distant from Earth.[1]


  1. ^ a b c Duerbeck, Hilmar W. (1981). "Light Curve Types, Absolute Magnitudes, and Physical Properties of Galactic Novae". Publications of the Astronomical Society of the Pacific. 93: 165–75. Bibcode:1981PASP...93..165D. doi:10.1086/130799. 
  2. ^ Burnham, Robert (2013) [1977]. Burnham's Celestial Handbook, Volume Three: An Observer's Guide to the Universe Beyond the Solar System. New York, New York: Courier Dover Publications. pp. 1460–62. ISBN 9780486318035. 
  3. ^ Ribeiro, Fabíola M. A.; Diaz, Marcos P. (2006). "A Tomographic Study of the Classical Nova RR Pictoris". Publications of the Astronomical Society of the Pacific. 118 (839): 84–93. arXiv:astro-ph/0510042free to read. Bibcode:2006PASP..118...84R. doi:10.1086/498458. JSTOR 498458.