CTA-102

{{Short description|Blazar-type quasar}}

{{Quasar

| name = CTA 102

| image =

| caption=

| epoch = J2000

| ra = {{RA|22|32|36.4}}{{cite web | url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=CTA+102 | title=CTA 102 in the NASA Extragalactic Database | accessdate=2008-12-24}}

| dec = {{DEC|+11|43|51s}}

| constellation name = Pegasus

| z = 1.037

| dist_ly = 8 billion light years{{Cite web |last=Christensen |first=Andrea |last2=University |first2=Brigham Young |date=19 December 2017 |title=Galaxy 8 billion light years away offers insight into supermassive black holes |url=https://phys.org/news/2017-12-galaxy-billion-years-insight-supermassive.html |access-date=5 August 2019 |website=Phys.org |language=en}}

| type =

| appmag_v =

| size_v =

| notes =

| names = CTA-102, Q2230+11, QSR B2230+114, QSO J2232+1143, 4C +11.69, PGC 2819036

}}

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 blazar-type quasar discovered in the early 1960s by a radio survey carried out by the California Institute of Technology. It has been observed by a large range of instruments since its discovery, including WMAP, EGRET, GALEX, VSOP and Parkes, and has been regularly imaged by the Very Long Baseline Array since 1995.{{cite web | url=http://www.physics.purdue.edu/MOJAVE/sourcepages/2230+114.shtml | title=MOJAVE Sample: 2230+114 | accessdate=2008-12-25 | archive-date=2016-08-06 | archive-url=https://web.archive.org/web/20160806174409/http://www.physics.purdue.edu/MOJAVE/sourcepages/2230+114.shtml | url-status=dead }} It has also been detected in gamma rays, and a gamma-ray flare has been detected from it.{{cite web | url=http://www.astronomerstelegram.org/?read=3320 | title=Fermi LAT detection of a GeV flare from blazar CTA 102 | publisher=Astronomers Telegram | date=3 May 2011 | accessdate=3 May 2011}}

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. Follow-up observations were announced in 1965 by Gennady Sholomitskii, who found that the object's radio emission was varying;{{cite journal | title=Variability of the Radio Source CTA-102 | last=Sholomitsky | first= G. B. | year=1965 | journal=Information Bulletin on Variable Stars | volume=83 | pages=1 | bibcode=1965IBVS...83....1S}} a public announcement of these results on April 12, 1965, caused a worldwide sensation.{{Cite web |last=Charbonneau |first=Rebecca |date=5 April 2023 |title=This Month in Astronomical History: April 2023 |url=https://aas.org/posts/news/2023/04/month-astronomical-history-april-2023 |website=American Astronomical Society}} 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.{{cite web | url=http://www.daviddarling.info/encyclopedia/C/CTA102.html | title=CTA-102 | publisher=Internet Encyclopedia of Space; David Darling | accessdate=2008-12-14}}

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.{{Cite book|last=Rogan|first=Johnny|authorlink=Johnny Rogan|pages=317–320|year=2011|title=Byrds: Requiem for the Timeless|publisher=Rogan House|isbn=978-0-95295-408-8}}

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).{{Cite news|url=http://www.skyandtelescope.com/observing/quasar-cta-102-historically-bright-violently-variable/|title = Quasar CTA 102: Historically Bright, Violently Variable| newspaper=Sky & Telescope |date = 23 November 2016}}{{cite web | url=http://www.astronomerstelegram.org/?read=9924 | title=Swift XRT and UVOT flares accompany brightest ever gamma-ray flare of CTA 102 | publisher=Astronomers Telegram | date=1 Jan 2017 | accessdate=23 July 2020}} This likely was the most luminous blazar state ever observed,{{cite web | url=http://www.astronomerstelegram.org/?read=9868 | title=CTA 102 brightens up to the most luminous optical blazar state ever detected. | publisher=Astronomers Telegram | date=16 Dec 2016 | accessdate=23 July 2020}} with an absolute magnitude in excess of -32.

A new outburst began in December 2017, with increased gamma-ray{{cite web | url=http://www.astronomerstelegram.org/?read=11045 | title=AGILE detection of increasing gamma-ray activity from CTA 102 | publisher=Astronomers Telegram | date=9 Dec 2017 | accessdate=23 July 2020}} and optical activity.{{cite web | url=http://www.astronomerstelegram.org/?read=11081 | title=CRTS-II Detection of Increased Optical Activity from CTA 102 | publisher=Astronomers Telegram | date=9 Dec 2017 | accessdate=23 July 2020}} As of 22 December 2017, it has reached magnitude +14.{{Cite web|url=https://www.aavso.org/apps/webobs/results/?start=2017-12-01&end=2017-12-23&num_results=25&obs_types=all&star=CTA+102|title = AAVSO – WebObs Search Results}}