From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
CTA 102
Observation data (Epoch J2000)
Right ascension 22h 32m 36.4s[1]
Declination+11° 43′ 51s″[1]
Other designations
CTA-102 , Q2230+11 , QSR B2230+114 , QSO J2232+1143 , 4C +11.69 ,
See also: Quasar, List of quasars

In astronomy, CTA 102, also known by its B1950 coordinates as 2230+114 (QSR B2230+114) and its J2000 coordinates as J2232+1143 (QSO J2232+1143), is a quasar discovered in the early 1960s by a radio survey carried out by the California Institute of Technology.[2] It has been observed by a large range of instruments since its discovery, including WMAP, EGRET, GALEX, VSOP and Parkes,[1] and has been regularly imaged by the Very Long Baseline Array since 1995.[3] It has also been detected in gamma rays, and a gamma-ray flare has been detected from it.[4]

In 1963 Nikolai Kardashev proposed that the then-unidentified radio source could be evidence of a Type II or III extraterrestrial civilization on the Kardashev scale.[2] Follow-up observations were announced in 1965 by Gennady Sholomitskii, who found that the object's radio emission was varying;[5] a public announcement of these results on April 12, 1965, caused a worldwide sensation.[6] The idea that the emission was caused by a civilization was rejected when the radio source was later identified as one of the many varieties of a quasar.[2]

CTA 102 is one of the two great false alarms in the history of SETI, the other being the discovery of pulsars, specifically PSR B1919+21, which are rotating neutron stars.

The American folk rock band The Byrds whimsically reflected the original view that CTA-102 was a sign of extraterrestrial intelligence in their song "C.T.A.-102" from their 1967 album Younger Than Yesterday.[7]

In late 2016 CTA 102, usually glowing around magnitude +17, had a bright outburst in visible light to magnitude +11 (~250 times brighter than usual).[8][9] This likely was the most luminous blazar state ever observed,[10] with an absolute magnitude in excess of -32.

A new outburst began in December 2017, with increased gamma-ray[11] and optical activity.[12] As of 22 December 2017, it has reached magnitude +14.[13]


  1. ^ a b c d "CTA 102 in the NASA Extragalactic Database". Retrieved 2008-12-24.
  2. ^ a b c "CTA-102". Internet Encyclopedia of Space; David Darling. Retrieved 2008-12-14.
  3. ^ "MOJAVE Sample: 2230+114". Retrieved 2008-12-25.
  4. ^ "Fermi LAT detection of a GeV flare from blazar CTA 102". Astronomers Telegram. 3 May 2011. Retrieved 3 May 2011.
  5. ^ Sholomitsky, G. B. (1965). "Variability of the Radio Source CTA-102". Information Bulletin on Variable Stars. 83: 1. Bibcode:1965IBVS...83....1S.
  6. ^ "Is Man Not Alone in the Universe? Space Signals Stir Experts", Milwaukee Sentinel, April 13, 1965, p1-3
  7. ^ Rogan, Johnny (2011). Byrds: Requiem for the Timeless. Rogan House. pp. 317–320. ISBN 978-0-95295-408-8.
  8. ^ http://www.skyandtelescope.com/observing/quasar-cta-102-historically-bright-violently-variable/
  9. ^ http://www.astronomerstelegram.org/?read=9924
  10. ^ http://www.astronomerstelegram.org/?read=9868
  11. ^ http://www.astronomerstelegram.org/?read=11045
  12. ^ http://www.astronomerstelegram.org/?read=11081
  13. ^ https://www.aavso.org/apps/webobs/results/?start=2017-12-01&end=2017-12-23&num_results=25&obs_types=all&star=CTA+102

See also[edit]