OJ 287 is a BL Lac object 4

billion Billion is a word for a large number, and it has two distinct definitions: * 1,000,000,000, i.e. one thousand million, or (ten to the ninth power), as defined on the short scale. This is now the most common sense of the word in all varieties of ...

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s 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, it was first detected at radio wavelengths during the course of the Ohio Sky Survey. It is a

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...

binary (SMBHB). 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.

Characteristics

Given the variability in the SMBHB's bursts and properties, multiple models have been proposed to account for these flashes. The initial model estimates the mass of the primary black hole to be approximately 18.35 billion

solar masses The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies ...

and the secondary black hole around 150 million solar masses. More recent models estimate that the central supermassive black hole has a mass of 100 million solar masses, much less than previous estimations. This would make its

Schwarzschild radius The Schwarzschild radius is a parameter in the Schwarzschild solution to Einstein's field equations that corresponds to the radius of a sphere in flat space that has the same surface area as that of the event horizon of a Schwarzschild black ho ...

about 1.97 AU. The optical light curve shows that OJ 287 has a periodic variation of 11–12 years with a narrow double peak at maximum brightness. This kind of variation suggests that it is a binary supermassive black hole. The double-burst variability is thought to result from the smaller

black hole A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

punching through the

accretion disc An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...

of the larger black hole twice in every 12 years. A secondary black hole orbits the larger one with an observed orbital period of approximately 12 years and a calculated

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-Centre (geometry), center, in geometry * Eccentricity (g ...

of approximately 0.65. The maximum brightness is obtained when the minor component moves through the

accretion disk An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and ...

of the supermassive component at perinigricon. The perinigricon and aponigricon of its orbit are about 3,250 and 17,500 AU. In recent models, the mass of the secondary

has been estimated to be approximately 125 million solar masses, although this has been debated through multiple studies. An international research group, led by Stefanie Komossa, calculated the mass of the primary black hole. "The results show that an exceptionally massive black hole exceeding 10 billion solar masses is no longer needed...the results favor models with a smaller mass of 100 million solar masses for the primary black hole". 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 The Kerr metric or Kerr geometry describes the geometry of empty spacetime around a rotating uncharged axially symmetric black hole with a quasispherical event horizon. The Kerr metric is an exact solution of the Einstein field equations of gen ...

. The companion's orbit is decaying via the emission of

gravitational radiation Gravitational waves are oscillations of the gravitational field that travel through space at the speed of light; they are generated by the relative motion of gravitating masses. They were proposed by Oliver Heaviside in 1893 and then later by ...

and it is expected to merge with the central black hole within approximately 10,000 years..

References

External links

*
18 Billions of Suns Support Einstein
(

Calar Alto Observatory The Calar Alto Observatory (Centro Astronómico Hispano en Andalucía or "Spanish Astronomical Centre in Andalusia") is an astronomical observatory located in Almería province in Spain on Calar Alto, a mountain in the Sierra de Los Filabre ...

)
Historical lightcurve of OJ 287

(SAO Observers)
OJ 287 2005-2008 Project
(Tuorla Observatory)
A Supermassive Black Hole Pairing
(Centauri Dreams)
Spitzer Telescope Reveals the Precise Timing of a Black Hole Dance

Refining the OJ 287 2022 impact flare arrival epoch

OJ 287: A new BH mass estimate of the secondary
{{DEFAULTSORT:OJ 287 BL Lacertae objects Quasars Supermassive black holes Cancer (constellation)