{{Short description|BL Lac object in the constellation Cancer}} {{Quasar | name = OJ 287 | image = SizesCompared-GalaxyOJ287CentralBlackHoles&SolarSystem.jpg | caption= Comparisons of large and small black holes in galaxy OJ 287 to the Solar System | epoch = J2000 | ra = {{RA|08|54|48.9}}<ref name="ned">{{cite web | work=NASA/IPAC Extragalactic Database | title=NED results for object OJ +287 | url=http://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=OJ+%2B287&extend=no&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES | access-date=2008-07-10 }}</ref> | dec = {{DEC|+20|06|31}}<ref name="ned" /> | constellation name = Cancer | z = 0.306000 <ref name="ned" /> | type = BL Lac<ref name="ned" /> | dist_ly = {{convert|4|Gly|Gpc|3|lk=on|abbr=on}} | appmag_v = 15.43<ref>{{cite simbad|title= QSO J0854+2006|access-date=15 March 2018}}</ref> | names = EGO 0851+202,<ref name="ned" /> 3EG J0853+1941,<ref name="ned" /> RGB J0854+201<ref name="ned" /> }}

'''OJ 287''' is a BL Lacertae object 4 billion light-years from Earth that has produced quasi-periodic optical outbursts going back approximately 120 years, as first apparent on photographic plates from 1891. Seen on photographic plates since at least 1887,<ref name=SnT-2015-01-13>{{cite news |url= http://www.skyandtelescope.com/astronomy-news/black-hole-binary-en-route-merger-0113201423/ |title= Black Hole Binary En Route to Merger? |date= 13 January 2015 |author= Camille M. Carlisle |publisher= Sky & Telescope }}</ref> it was first detected at radio wavelengths during the course of the Ohio Sky Survey. It is a supermassive black hole binary (SMBHB).<ref name="Laine2020">{{cite journal |last1=Laine |first1=S. |last2=Dey |first2=L. |last3=Valtonen |first3=M. |last4=Gopakumar |first4=A. |last5=Zola |first5=S. |last6=Komossa |first6=S. |last7=Kidger |first7=M. |last8=Pihajoki |first8=P. |last9=Gómez |first9=J.L. |last10=Caton |first10=D. |last11=Ciprini |first11=S. |last12=Drozdz |first12=M. |last13=Gazeas |first13=K. |last14=Godunova |first14=V. |last15=Haque |first15=S. |year=2020 |title=Spitzer Observations of the Predicted Eddington Flare from Blazar OJ 287 |url=https://authors.library.caltech.edu/102834/1/Laine_2020_ApJL_894_L1.pdf |journal=The Astrophysical Journal |volume=894 |issue=1 |pages=L1 |arxiv=2004.13392 |bibcode=2020ApJ...894L...1L |doi=10.3847/2041-8213/ab79a4 |doi-access=free |last16=Hildebrandt |first16=F. |last17=Hudec |first17=R. |last18=Jermak |first18=H. |last19=Kong |first19=A.K.H. |last20=Lehto |first20=H. |last21=Liakos |first21=A. |last22=Matsumoto |first22=K. |last23=Mugrauer |first23=M. |last24=Pursimo |first24=T. |last25=Reichart |first25=D.E. |last26=Simon |first26=A. |last27=Siwak |first27=M. |last28=Sonbas |first28=E. |s2cid=216562421}}</ref> The intrinsic brightness of the flashes corresponds to over a trillion times the Sun's luminosity, greater than the entire Milky Way galaxy's light output.<ref name="JPL2020-04" />

==Characteristics== Given the variability in the SMBHB's bursts and properties, multiple models have been proposed to account for these flashes. Analysis of a light curve spanning 130 years give a mass for the central black hole to be {{solar mass|18,350,000,000}}.<ref name=Valtonen>{{Cite journal |last1=Valtonen |first1=Mauri J. |last2=Zola |first2=Staszek |last3=Gopakumar |first3=Achamveedu |last4=Lähteenmäki |first4=Anne |last5=Tornikoski |first5=Merja |last6=Dey |first6=Lankeswar |last7=Gupta |first7=Alok C. |last8=Pursimo |first8=Tapio |last9=Knudstrup |first9=Emil |last10=Gomez |first10=Jose L. |last11=Hudec |first11=Rene |last12=Jelínek |first12=Martin |last13=Štrobl |first13=Jan |last14=Berdyugin |first14=Andrei V. |last15=Ciprini |first15=Stefano |date=2023-08-09 |title=On the need of an ultramassive black hole in OJ 287 |journal=Monthly Notices of the Royal Astronomical Society |volume=525 |issue=1 |pages=1153–1157 |doi=10.1093/mnras/stad2249 |doi-access=free |arxiv=2308.03017 |issn=0035-8711}}</ref> thumb|left|Black Hole Disk Flares In Galaxy OJ 287 (1:22; animation; 28 April 2020) [[File:Observing—and Imaging—Active Galactic Nuclei with the Event Horizon Telescope Fig4a.png|thumb|Interferometric observations of OJ287 by the VLBA resolved with the CHIRP algorithm and another algorithm by a group from Boston university.<ref>{{Cite journal |last1=Fish |first1=Vincent |last2=Akiyama |first2=Kazunori |last3=Bouman |first3=Katherine |last4=Chael |first4=Andrew |last5=Johnson |first5=Michael |last6=Doeleman |first6=Sheperd |last7=Blackburn |first7=Lindy |last8=Wardle |first8=John |last9=Freeman |first9=William |last10=the Event Horizon Telescope Collaboration |date=2016-10-27 |title=Observing—and Imaging—Active Galactic Nuclei with the Event Horizon Telescope |journal=Galaxies |language=en |volume=4 |issue=4 |pages=54 |doi=10.3390/galaxies4040054 |arxiv=1607.03034 |bibcode=2016Galax...4...54F |issn=2075-4434|doi-access=free }}</ref> OJ287 is a target candidate of the Event Horizon Telescope; 3C279 was targeted by it in 2017.]] The optical light curve shows that OJ&nbsp;287 has a periodic variation of 11–12&nbsp;years with a narrow double peak at maximum brightness.<ref>{{cite journal|title=A new model for the periodic outbursts of the BL Lac object OJ287| last1=Shi| first1=Weizhao| last2=Liu | first2=Xiang | last3=Song | first3=Huagang | journal=Astrophysics and Space Science| volume=310| issue= 1–2| pages= 59–63| date=2007| doi=10.1007/s10509-007-9413-z|bibcode = 2007Ap&SS.310...59S | s2cid=121149840}}</ref> This kind of variation suggests that it is a binary supermassive black hole.<ref>{{Cite journal | last1 = Valtonen | first1 = M. J. | last2 = Nilsson | first2 = K. | last3 = Sillanpää | first3 = A. | last4 = Takalo | first4 = L. O. | last5 = Lehto | first5 = H. J. | last6 = Keel | first6 = W. C. | last7 = Haque | first7 = S. | last8 = Cornwall | first8 = D. | last9 = Mattingly | first9 = A. | display-authors = 3 | title = The 2005 November Outburst in OJ 287 and the Binary Black Hole Model | doi = 10.1086/505039 | journal = The Astrophysical Journal | volume = 643 | issue = 1 | pages = L9–L12 | year = 2006 |bibcode = 2006ApJ...643L...9V | doi-access = free }}</ref> The double-burst variability is thought to result from the smaller black hole punching through the accretion disc of the larger black hole twice in every 12 years.<ref name="JPL2020-04">{{cite web |url= https://www.jpl.nasa.gov/news/news.php?release=2020-080|title= Spitzer Telescope Reveals the Precise Timing of a Black Hole Dance|date= 28 April 2020|website= JPL.NASA.gov|publisher= Jet Propulsion Laboratory|access-date= 2020-05-03}}</ref>

A secondary black hole orbits the larger one with an observed orbital period of approximately 12 years and a calculated eccentricity of approximately 0.65.<ref name="Laine2020" /> The maximum brightness is obtained when the minor component moves through the accretion disk of the supermassive component at perinigricon. The perinigricon and aponigricon of its orbit are about 3,250 and 17,500&nbsp;AU.{{Citation needed|date=June 2025}} In recent models, the mass of the secondary supermassive black hole has been estimated to be approximately 150 million solar masses.<ref name=Valtonen/>

An independent Swift/XRT X-ray spectral analysis based on the bulk-motion Comptonization scaling method yielded a comparable estimate of about 2 × 10^8 solar masses for the secondary component of the binary, although the authors noted that this interpretation depends on the assumption that a significant fraction of the observed X-ray emission is produced by bulk-motion Comptonization rather than being jet-dominated.<ref name="Kuznetsov2024MNRAS">{{cite journal |last1=Kuznetsov |first1=Sergey |title=Black hole mass estimate in OJ 287 based on the bulk-motion comptonization model |journal=Monthly Notices of the Royal Astronomical Society |year=2024 |volume=535 |issue=4 |pages=3732–3737 |doi=10.1093/mnras/stae2596 |url=https://academic.oup.com/mnras/article/535/4/3732/7905873 |doi-access=free }}</ref>

An international collaboration led by Stefanie Komossa reported that a predicted major outburst of OJ 287 in October 2022 was not observed. This absence places constraints on specific binary supermassive black hole scenarios and on models that require extremely high primary black hole masses with precise orbital timing.<ref name="Komossa2023MNRASL">{{cite journal |last1=Komossa |first1=Stefanie |last2=Grupe |first2=Dirk |last3=Kraus |first3=Alexander |title=Absence of the predicted 2022 October outburst of OJ 287 and implications for binary SMBH scenarios |journal=Monthly Notices of the Royal Astronomical Society: Letters |year=2023 |volume=522 |issue=1 |pages=L84–L88 |doi=10.1093/mnrasl/slad016 |url=https://academic.oup.com/mnrasl/article/522/1/L84/7044769 |display-authors=etal |doi-access=free |arxiv=2302.11646 }}</ref>

Other analyses argue that an ultramassive primary black hole is still required to reproduce the historical outburst record.<ref name="Valtonen"/>

In order to reproduce all the known outbursts, the rotation of the primary black hole is calculated to be 38% of the maximum allowed rotation for a Kerr black hole.<ref>{{cite journal|doi=10.1088/0004-637X/709/2/725|title=Measuring the Spin of the Primary Black Hole in OJ287| last1=Valtonen|first1= M. J. |last2=Mikkola|first2= S.|author2-link=Seppo Mikkola|last3=Merritt|first3= D.|author3-link=David Merritt|last4=Gopakumar|first4= A.| last5=Lehto|first5= H. J.|last6= Hyvönen|first6=T.|last7=Rampadarath|first7=H.|last8= Saunders|first8=R.|last9=Basta|first9=M.|last10=Hudec|first10=R. | display-authors = 3 | journal=The Astrophysical Journal| volume= 709| issue= 1| pages= 725–732|date=February 2010| bibcode=2010ApJ...709..725V|arxiv = 0912.1209|s2cid=119276181}}</ref><ref name="Laine2020" />

The companion's orbit is decaying via the emission of gravitational radiation and it is expected to merge with the central black hole within approximately 10,000&nbsp;years.<ref name="newscientist">{{cite news |last=Shiga |first=David |date=10 January 2008 |title=Biggest black hole in the cosmos discovered |publisher=NewScientist.com news service |url=https://www.newscientist.com/article/dn13166-biggest-black-hole-in-the-cosmos-discovered.html}}</ref><ref>{{Cite journal | last1 = Valtonen | first1 = M. J. | last2 = Lehto | first2 = H. J. | last3 = Sillanpaa | first3 = A. | last4 = Nilsson | first4 = K. | last5 = Mikkola | first5 = S. | last6 = Hudec | first6 = R. | last7 = Basta | first7 = M. | last8 = Terasranta | first8 = H. | last9 = Haque | first9 = S. | last10 = Rampadarath | first10 = H. | display-authors = 3 | title = Predicting the Next Outbursts of OJ 287 in 2006–2010 | doi = 10.1086/504884 | journal = The Astrophysical Journal | volume = 646 | issue = 1 | pages = 36–48 | year = 2006 |bibcode = 2006ApJ...646...36V | doi-access = free }}.</ref><ref name="Dey2019">{{cite journal |last1=Dey |first1=L. |last2=Gopakumar |first2=A. |last3=Valtonen |first3=M. |last4=Zola |first4=S. |last5=Susobhanan |first5=A. |last6=Hudec |first6=R. |last7=Pihajoki |first7=P. |last8=Pursimo |first8=T. |last9=Berdyugin |first9=A. |last10=Piirola |first10=V. |last11=Ciprini |first11=S. |last12=Nilsson |first12=K. |last13=Jermak |first13=H. |last14=Kidger |first14=M. |last15=Komossa |first15=S. |year=2019 |title=The Unique Blazar OJ 287 and Its Massive Binary Black Hole Central Engine |journal=Universe |volume=5 |issue=5 |pages=108 |arxiv=1905.02689 |bibcode=2019Univ....5..108D |doi=10.3390/universe5050108 |doi-access=free |s2cid=146808185}}</ref>

==References== {{reflist}}

==External links== * {{WikiSky|z=12}} * [https://web.archive.org/web/20150912112348/http://www.caha.es/18-billions-of-suns-support-einstein.html 18 Billions of Suns Support Einstein] (Calar Alto Observatory) * [http://www.astro.utu.fi/OJ287MMVI/img/OJ287opticalhistorical.gif Historical lightcurve of OJ 287] * [http://astronomy.swin.edu.au/sao/SAO_Observers/OJ287.html Object: OJ 287] {{Webarchive|url=https://web.archive.org/web/20060925173343/http://astronomy.swin.edu.au/sao/SAO_Observers/OJ287.html |date=2006-09-25 }} (SAO Observers) * [http://www.astro.utu.fi/OJ287MMVI/ OJ 287 2005-2008 Project] (Tuorla Observatory) * [http://www.centauri-dreams.org/?p=644 A Supermassive Black Hole Pairing] (Centauri Dreams) * [https://www.jpl.nasa.gov/news/news.php?release=2020-080 Spitzer Telescope Reveals the Precise Timing of a Black Hole Dance] * [https://academic.oup.com/mnras/article/521/4/6143/7086128?login=false#407231012 Refining the OJ 287 2022 impact flare arrival epoch] * [https://www.researchgate.net/publication/368662047_OJ_287_A_new_BH_mass_estimate_of_the_secondary OJ 287: A new BH mass estimate of the secondary]

{{Sky|08|54|48.9|+|20|06|31|3500000000}} {{Stars of Cancer}} {{Portal bar|Astronomy|Stars|Outer space|Science}}

{{DEFAULTSORT:OJ 287}} Category:BL Lacertae objects Category:Quasars Category:Supermassive black holes Category:Cancer (constellation) Category:Binary systems