CTA 102, also known by its
B1950 coordinates as 2230+114 (QSR B2230+114) and its
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to ...
coordinates as J2232+1143 (QSO J2232+1143), is a
blazar
A blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet composed of ionized matter traveling at nearly the speed of light) directed very nearly towards an observer. Relativistic beaming of electromagnetic radiation from the ...
-type
quasar
A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...
discovered in the early 1960s by a radio survey carried out by the
California Institute of Technology
The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...
.
It has been observed by a large range of instruments since its discovery, including
WMAP
The Wilkinson Microwave Anisotropy Probe (WMAP), originally known as the Microwave Anisotropy Probe (MAP and Explorer 80), was a NASA spacecraft operating from 2001 to 2010 which measured temperature differences across the sky in the cosmic mic ...
,
EGRET
Egrets ( ) are herons, generally long-legged wading birds, that have white or buff plumage, developing fine plumes (usually milky white) during the breeding season. Egrets are not a biologically distinct group from herons and have the same build ...
,
GALEX,
VSOP and
Parkes,
and has been regularly imaged by the
Very Long Baseline Array since 1995.
It has also been detected in
gamma rays
A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...
, and a gamma-ray flare has been detected from it.
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
The Kardashev scale () is a method of measuring a civilization's level of technology, technological advancement based on the amount of energy it is capable of harnessing and using. The measure was proposed by Soviet astronomer Nikolai Kardashev i ...
.
Follow-up observations were announced in 1965 by Gennady Sholomitskii, who found that the object's radio emission was varying;
a public announcement of these results on April 12, 1965, caused a worldwide sensation. 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
A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...
.
The American
folk rock
Folk rock is a fusion genre of rock music with heavy influences from pop, English and American folk music. It arose in the United States, Canada, and the United Kingdom in the mid-1960s. In the U.S., folk rock emerged from the folk music re ...
band
The Byrds
The Byrds () were an American Rock music, rock band formed in Los Angeles, California, in 1964. The band underwent multiple lineup changes throughout its existence, with frontman Roger McGuinn (known as Jim McGuinn until mid-1967) being the so ...
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
''Younger Than Yesterday'' is the fourth studio album by the American rock band the Byrds, released on February 6, 1967, by Columbia Records. It saw the band continuing to integrate elements of psychedelic music, psychedelia and jazz into their ...
''.
In late 2016 CTA 102, usually glowing around
magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
+17, had a bright outburst in visible light to magnitude +11 (~250 times brighter than usual). This likely was the most luminous
blazar
A blazar is an active galactic nucleus (AGN) with a relativistic jet (a jet composed of ionized matter traveling at nearly the speed of light) directed very nearly towards an observer. Relativistic beaming of electromagnetic radiation from the ...
state ever observed, with an
absolute magnitude in excess of -32.
A new outburst began in December 2017, with increased gamma-ray and optical activity. As of 22 December 2017, it has reached magnitude +14.
See also
*
PSR B1919+21, the first pulsar discovered, mistaken for an alien radio signal
*
HD 164595
References
{{Extraterrestrial life
Search for extraterrestrial intelligence
2819036
Quasars
Pegasus (constellation)