Circumbinary planet

The first confirmed circumbinary planet was found orbiting the system PSR B1620-26, which contains a millisecond pulsar and a white dwarf and is located in the globular cluster M4. The existence of the third body was first reported in 1993,{{cite conference|author=Backer, D.C.|title=A pulsar timing tutorial and NRAO Green Bank observations of PSR 1257+12|year=1993|book-title=Planets around Pulsars|publisher=California Institute of Technology|location=Pasadena|pages=11–18|bibcode=1993ASPC...36...11B}} and was suggested to be a planet based on 5 years of observational data. In 2003 the planet was characterised as being 2.5 times the mass of Jupiter in a low eccentricity orbit with a semimajor axis of 23 AU.{{cite journal|author1=Sigurðsson, Steinn |author2=Richer, Harvey B. |author3=Hansen, Brad M. |author4=Stairs, Ingrid H. |author5=Thorsett, Stephen E. |title=A Young White Dwarf Companion to Pulsar B1620-26: Evidence for Early Planet Formation|journal=Science|volume=301|issue=5630|pages=193–196|year=2003|doi=10.1126/science.1086326|bibcode=2003Sci...301..193S|pmid=12855802|arxiv = astro-ph/0307339 |s2cid=39446560 }}

The first circumbinary planet around a main sequence star was found in 2005 in the system HD 202206: a Jupiter-size planet orbiting a system composed of a Sun-like star and a brown dwarf.

HD 202206 is a Sun-like star orbited by two objects, one of 17 M_J and one of 2.4 M_J. The classification of HD 202206 b as a brown dwarf or "superplanet" is now clear. HD 202206 b is actually a red dwarf with 0.089 solar masses. The two objects could have both formed in a protoplanetary disk with the inner one becoming a superplanet, or the outer planet could have formed in a circumbinary disk.

A dynamical analysis of the system further shows a 5:1 mean motion resonance between the planet and the brown dwarf.

These observations raise the question of how this system was formed, but numerical simulations show that a planet formed in a circumbinary disk can migrate inward until it is captured in resonance.{{cite journal|author=Nelson, Richard P.|title=On the evolution of giant protoplanets forming in circumbinary discs|journal=Monthly Notices of the Royal Astronomical Society

|volume=345|issue=1|pages=233–242|year=2003|doi=10.1046/j.1365-8711.2003.06929.x|bibcode=2003MNRAS.345..233N|doi-access=free}}

On 15 September 2011, astronomers, using data from NASA's Kepler space telescope, announced the first partial-eclipse-based discovery of a circumbinary planet.Doyle, Laurance, et al. Science, 16 September 2011."Kepler uncovers planet orbiting two stars", Astronomy, January 2012, p. 23. The planet, called Kepler-16b, is about 200 light years from Earth, in the constellation Cygnus, and is believed to be a frozen world of rock and gas, about the mass of Saturn. It orbits two stars that are also circling each other, one about two-thirds the size of the Sun, the other about a fifth the size of the Sun. Each orbit of the stars by the planet takes 229 days, while the planet orbits the system's center of mass every 225 days; the stars eclipse each other every three weeks or so.

In 2012 volunteers of the Planet Hunters project discovered PH1b (Planet Hunters 1 b), a circumbinary planet in a quadruple star system.{{Cite web|url=https://blog.planethunters.org/2012/10/15/ph1-a-planet-in-a-four-star-system/|title=PH1: A planet in a four-star system|last=chrislintott|date=2012-10-15|website=Planet Hunters|language=en|access-date=2020-02-14}}

In 2015, astronomers confirmed the existence of Kepler-453b, a circumbinary planet with orbital period of 240.5 days.

A new planet, called Kepler-1647b, was announced on June 13, 2016. It was discovered using the Kepler telescope. The planet is a gas giant, similar in size to Jupiter which makes it the second largest circumbinary planet ever discovered, next to PSR B1620-26. It is located in the stars' habitable zone, and it orbits the star system in 1107 days, which makes it the longest period of any confirmed transiting exoplanet so far.

A massive planet or brown dwarf around this low-mass X-ray binary (LMXB) system was found by the method of periodic delay in X-ray eclipses.

A large planet called TOI-1338 b, around 6.9 times as large as Earth and 1,300 light years away, was announced on January 6, 2020.{{Cite web|url=https://svs.gsfc.nasa.gov/13510|title=GMS: TESS Satellite Discovered Its First World Orbiting Two Stars|website=svs.gsfc.nasa.gov|date=6 January 2020 |access-date=2020-01-16}}

File:AK Scorpii.png, a young system in the constellation Scorpius. The image of the disk was taken with ALMA.]]

Claims of a planet discovered via microlensing, orbiting the close binary pair MACHO-1997-BLG-41, were announced in 1999.{{cite journal|author1=Bennett, D. P. |author2=Rhie, S. H. |author3=Becker, A. C. |author4=Butler, N. |author5=Dann, J. |author6=Kaspi, S. |author7=Leibowitz, E. M. |author8=Lipkin, Y. |author9=Maoz, D. |author10=Mendelson, H. |author11=Peterson, B. A. |author12=Quinn, J. |author13=Shemmer, O. |author14=Thomson, S. |author15=Turner, S. E. |title=Discovery of a planet orbiting a binary star system from gravitational microlensing|journal=Nature|volume=402|issue=6757|pages=57–59|year=1999|doi=10.1038/46990|bibcode=1999Natur.402...57B|arxiv = astro-ph/9908038 |s2cid=205061885 |url=https://digital.library.unt.edu/ark:/67531/metadc1225792/ |type=Submitted manuscript }} The planet was said to be in a wide orbit around the two red dwarf companions, but the claims were later retracted, as it turned out the detection could be better explained by the orbital motion of the binary stars themselves.{{cite journal|author1=Albrow, M. D. |author2=Beaulieu, J.-P. |author3=Caldwell, J. A. R. |author4=Dominik, M. |author5=Gaudi, B. S. |author6=Gould, A. |author7=Greenhill, J. |author8=Hill, K. |author9=Kane, S. |author10=Martin, R. |author11=Menzies, J. |author12=Naber, R. M. |author13=Pollard, K. R. |author14=Sackett, P. D. |author15=Sahu, K. C. |author16=Vermaak, P. |author17=Watson, R. |author18=Williams, A. |author19=Bond, H. E. |author20=van Bemmel, I. M. |title=Detection of Rotation in a Binary Microlens: PLANET Photometry of MACHO 97-BLG-41|journal=The Astrophysical Journal|year=2000|volume=534|issue=2|pages=894–906|doi=10.1086/308798|bibcode=2000ApJ...534..894A|arxiv = astro-ph/9910307 |s2cid=3000437 |url=https://cds.cern.ch/record/403976 |type=Submitted manuscript }}

Several attempts have been made to detect planets around the eclipsing binary system CM Draconis, itself part of the triple system GJ 630.1. The eclipsing binary has been surveyed for transiting planets, but no conclusive detections were made and eventually the existence of all the candidate planets was ruled out.{{cite web|url=http://www.iac.es/project/tep/tephome.html|title=The TEP network}}{{cite journal|title=Observational Limits on Terrestrial-sized Inner Planets around the CM Draconis System Using the Photometric Transit Method with a Matched-Filter Algorithm|author1=Doyle, Laurance R. |author2=Deeg, Hans J. |author3=Kozhevnikov, Valerij P. |author4=Oetiker, Brian |author5=Martín, Eduardo L. |author6=Blue, J. Ellen |author7=Rottler, Lee |author8=Stone, Remington P. S. |author9=Ninkov, Zoran |author10=Jenkins, Jon M. |author11=Schneider, Jean |author12=Dunham, Edward W. |author13=Doyle, Moira F. |author14=Paleologou, Efthimious |journal=The Astrophysical Journal|volume=535|issue=1|pages=338–349|year=2000|doi=10.1086/308830|bibcode=2000ApJ...535..338D|arxiv = astro-ph/0001177 |s2cid=18639250 }} More recently, efforts have been made to detect variations in the timing of the eclipses of the stars caused by the reflex motion associated with an orbiting planet, but at present no discovery has been confirmed. The orbit of the binary stars is eccentric, which is unexpected for such a close binary as tidal forces ought to have circularised the orbit. This may indicate the presence of a massive planet or brown dwarf in orbit around the pair whose gravitational effects maintain the eccentricity of the binary.{{cite journal|author1=Morales, Juan Carlos |author2=Ribas, Ignasi |author3=Jordi, Carme |author3-link=Carme Jordi|author4=Torres, Guillermo |author5=Gallardo, José |author6=Guinan, Edward F. |author7=Charbonneau, David |author8=Wolf, Marek |author9=Latham, David W. |author10=Anglada-Escudé, Guillem |author11=Bradstreet, David H. |author12=Everett, Mark E. |author13=O'Donovan, Francis T. |author14=Mandushev, Georgi |author15=Mathieu, Robert D. |title=Absolute Properties of the Low-Mass Eclipsing Binary CM Draconis|journal=The Astrophysical Journal|volume=691|issue=2|pages=1400–1411|year=2009|doi=10.1088/0004-637X/691/2/1400|bibcode=2009ApJ...691.1400M|arxiv = 0810.1541 |s2cid=3752277 }}

Circumbinary discs that may indicate processes of planet formation have been found around several stars, and are in fact common around binaries with separations less than 3 AU.{{cite news|title=Worlds with Double Sunsets Common|agency=Space.com|author=Ker Than|url=http://www.space.com/scienceastronomy/070329_double_sunsets.html|date=2007-03-07}}{{cite journal|author1=Trilling, D. E. |author2=Stansberry, J. A. |author3=Stapelfeldt, K. R. |author4=Rieke, G. H. |author5=Su, K. Y. L. |author6=Gray, R. O. |author7=Corbally, C. J. |author8=Bryden, G. |author9=Chen, C. H. |author10=Boden, A. |author11=Beichman, C. A. |title=Debris disks in main-sequence binary systems.|journal=The Astrophysical Journal|volume=658|issue=2|pages=1264–1288|year=2007|doi=10.1086/511668|bibcode=2007ApJ...658.1289T|arxiv = astro-ph/0612029 |s2cid=14867168 }} One notable example is in the HD 98800 system, which comprises two pairs of binary stars separated by around 34 AU. The binary subsystem HD 98800 B, which consists of two stars of 0.70 and 0.58 solar masses in a highly eccentric orbit with semimajor axis 0.983 AU, is surrounded by a complex dust disc that is being warped by the gravitational effects of the mutually-inclined and eccentric stellar orbits.{{cite journal|author1=Akeson, R. L. |author2=Rice, W. K. M. |author3=Boden, A. F. |author4=Sargent, A. I. |author5=Carpenter, J. M. |author6=Bryden, G. |title=The Circumbinary Disk of HD 98800B: Evidence for Disk Warping|year=2007|journal=The Astrophysical Journal|volume=670|issue=2|pages=1240–1246|doi=10.1086/522579|bibcode=2007ApJ...670.1240A|arxiv = 0708.2390 |s2cid=7584467 }}{{cite journal|author1=Verrier, P. E. |author2=Evans, N. W. |title=HD 98800: a most unusual debris disc|journal=Monthly Notices of the Royal Astronomical Society|volume=390|issue=4|pages=1377–1387|year=2008|doi=10.1111/j.1365-2966.2008.13854.x|doi-access=free |bibcode=2008MNRAS.390.1377V|arxiv = 0807.5105 |s2cid=119182238 }} The other binary subsystem, HD 98800 A, is not associated with significant amounts of dust.{{cite journal|author1=Prato, L. |author2=Ghez, A. M. |author3=Piña, R. K. |author4=Telesco, C. M. |author5=Fisher, R. S. |author6=Wizinowich, P. |author7=Lai, O. |author8=Acton, D. S. |author9=Stomski, P. |title=Keck Diffraction-limited Imaging of the Young Quadruple Star System HD 98800|journal=The Astrophysical Journal|volume=549|issue=1|pages=590–598|year=2001|doi=10.1086/319061|bibcode=2001ApJ...549..590P|arxiv = astro-ph/0011135 |s2cid=1575520 }}

Announced in 2008, the eclipsing binary system HW Virginis, comprising a subdwarf B star and a red dwarf, was claimed to also host a planetary system. The claimed planets have masses at least 8.47 and 19.23 times that of Jupiter respectively, and were proposed to have orbital periods of 9 and 16 years. The proposed outer planet is sufficiently massive that it may be considered to be a brown dwarf under some definitions of the term,{{cite web|url=http://www.dtm.ciw.edu/users/boss/definition.html|title=Definition of a "Planet"|publisher=Working Group on Extrasolar Planets (WGESP) of the International Astronomical Union|access-date=2009-07-04}} but the discoverers claimed that the orbital configuration implies it would have formed like a planet from a circumbinary disc. Both planets may have accreted additional mass when the primary star lost material during its red giant phase.{{cite journal|title=The sdB+M Eclipsing System HW Virginis and its Circumbinary Planets|author1=Lee, Jae Woo |author2=Kim, Seung-Lee |author3=Kim, Chun-Hwey |author4=Koch, Robert H. |author5=Lee, Chung-Uk |author6=Kim, Ho-Il |author7=Park, Jang-Ho |year=2009|journal=The Astronomical Journal|volume=137|issue=2|pages=3181–3190|doi=10.1088/0004-6256/137/2/3181|bibcode=2009AJ....137.3181L|arxiv = 0811.3807 |s2cid=14152006 }}

Further work on the system{{cite journal|title=A dynamical analysis of the proposed circumbinary HW Virginis planetary system|author1=Horner, J.|author2=Wittenmyer, R. A.|author3=Marshall, J. P.|author4=Tinney, C. G.|year=2012|journal=Monthly Notices of the Royal Astronomical Society|volume=427|issue=4|pages=2812–2823|doi=10.1111/j.1365-2966.2012.22046.x|doi-access=free |bibcode=2012MNRAS.427.2812H|arxiv = 1209.0608 |s2cid=53349383 }} showed that the orbits proposed for the candidate planets were catastrophically unstable on timescales far shorter than the age of the system. Indeed, the authors found that the system was so unstable that it simply cannot exist, with mean lifetimes of less than a thousand years across the whole range of plausible orbital solutions. Like other planetary systems proposed around similar evolved binary star systems, it seems likely that some mechanism other than claimed planets is responsible for the observed behaviour of the binary stars – and that the claimed planets simply do not exist.

The Kepler space telescope results indicate circumbinary planetary systems are relatively common (as of October 2013 the spacecraft had found seven planets out of roughly 1000 eclipsing binaries searched).

There is a wide range of stellar configurations for which circumbinary planets can exist. Primary star masses range from 0.69 to 1.53 solar masses (Kepler-16 A and PH1 Aa), star mass ratios from 1.03 to 3.76 (Kepler-34 and PH1), and binary eccentricity from 0.023 to 0.521 (Kepler-47 and Kepler-34). The distribution of planet eccentricities, range from nearly circular e=0.007 to a significant e=0.182 (Kepler-16 and Kepler-34). No orbital resonances with the binary have been found.

The binary stars Kepler-34 A and B have a highly eccentric orbit (e = 0.521) around each other and

their interaction with the planet is strong enough that a deviation from Kepler's laws is noticeable after just one orbit.{{clarify|reason=What kind of deviation, and how does the planet affect it?|date=May 2018}}

All Kepler circumbinary planets that were known as of August 2013 orbit their stars very close to the plane of the binary (in a prograde direction) which suggests a single-disk formation. However, not all circumbinary planets are co-planar with the binary: Kepler-413b is tilted 2.5 degrees which may be due to the gravitational influence of other planets or a third star. Taking into account the selection biases, the average mutual inclination between the planetary orbits and the stellar binaries is within ~3 degrees, consistent with the mutual inclinations of planets in multi-planetary systems.

The axial tilt of Kepler-413b's spin axis might vary by as much as 30 degrees over 11 years, leading to rapid and erratic changes in seasons.

Simulations show that it is likely that all of the circumbinary planets known prior to a 2014 study migrated significantly from their formation location with the possible exception of Kepler-47 (AB)c.{{cite journal | arxiv=1402.0509 | doi=10.1088/2041-8205/782/1/L11 | title=FORMING CIRCUMBINARY PLANETS: N -BODY SIMULATIONS OF KEPLER-34 | date=2014 | last1=Lines | first1=S. | last2=Leinhardt | first2=Z. M. | last3=Paardekooper | first3=S. | last4=Baruteau | first4=C. | last5=Thebault | first5=P. | journal=The Astrophysical Journal | volume=782 | issue=1 | pages=L11 | bibcode=2014ApJ...782L..11L }}

The minimum stable star to circumbinary planet separation is about 2–4 times the binary star separation, or orbital period about 3–8 times the binary period. The innermost planets in all the Kepler circumbinary systems have been found orbiting close to this radius. The planets have semi-major axes that lie between 1.09 and 1.46 times this critical radius. The reason could be that migration might become inefficient near the critical radius, leaving planets just outside this radius.

Recently, it has been found that the distribution of the innermost planetary semi-major axes is consistent with a log-uniform distribution, taking into account the selection biases, where closer-in planets can be detected more easily. This questions the pile-up of planets near the stability limit as well as the dominance of planet migration.

Most Kepler eclipsing binaries have periods less than 1 day but the shortest period of a Kepler eclipsing binary hosting a planet is 7.4 days (Kepler-47). The short-period binaries are unlikely to have formed in such a tight orbit and their lack of planets may be related to the mechanism that removed angular momentum allowing the stars to orbit so closely. One exception is the planet around an X-ray binary MXB 1658-298, which has an orbital period of 7.1 hours.

As of June 2016, all but one of the confirmed Kepler circumbinary planets are smaller than Jupiter. This cannot be a selection effect because larger planets are easier to detect. Simulations had predicted this would be the case.{{cite journal | arxiv=0803.2000 | doi=10.1051/0004-6361:200809453 | title=On the formation and migration of giant planets in circumbinary discs | date=2008 | last1=Pierens | first1=A. | last2=Nelson | first2=R. P. | journal=Astronomy & Astrophysics | volume=483 | issue=2 | pages=633–642 | bibcode=2008A&A...483..633P }}

{{main|Habitability of binary star systems}}

All the Kepler circumbinary planets are either close to or actually in the habitable zone. None of them are terrestrial planets, but large moons of such planets could be habitable. Because of the stellar binarity, the insolation received by the planet will likely be time-varying in a way quite unlike the regular sunlight Earth receives.

Circumbinary planets are generally more likely to transit than planets around a single star. The probability when the planetary orbit overlaps with the stellar binary orbit has been obtained.{{Cite journal|last1=Martin|first1=David|last2=Triaud|first2=Amaury|title=Circumbinary planets – why they are so likely to transit|journal= Monthly Notices of the Royal Astronomical Society|volume=449|issue=1|doi=10.1093/mnras/stv121|year=2015|pages=781–793|doi-access=free |arxiv=1501.03631|bibcode=2015MNRAS.449..781M}} For planets orbiting eclipsing stellar binaries (such as the detected systems), the analytical expression of the transit probability in a finite observation time has been obtained.

Circumbinary planets should preferentially be icy, not rocky.{{cite journal | arxiv=2403.04535 | last1=Pierens | first1=Arnaud | last2=Nelson | first2=Richard P. | title=Thermal structure of circumbinary discs: Circumbinary planets should be icy not rocky | journal=Astronomy and Astrophysics | date=2024 | volume=686 | pages=A103 | doi=10.1051/0004-6361/202449237 | bibcode=2024A&A...686A.103P }}

{{update section|date=April 2023}}

The claimed circumbinary planet in the microlensing event MACHO-1997-BLG-41 has been disproven. The circumbinary companion to FW Tauri was once thought to be planetary-mass, but has been shown to be a low-mass star of about {{Solar mass|0.1|link=y}}, forming a triple star system.

A strong candidate for a circumbinary planet in a polar orbit around 2M1510, a binary brown dwarf, was announced in 2025. The discovery was made with the Very Large Telescope.

A co-moving object was discovered around the resolved binary or triple star system 2M1006 (CPD-63 1286). The candidate co-moves with the triple with a separation of around 730 AU. It was not possible to determine if the candidate orbit the star system, because the barycenter was not known at the time of discovery. If it has the same age as the primary star, the candidate should have a mass of 3-5 {{jupiter mass}}, and therefore could be a low-mass planet like AF Lep b or 51 Eri b.

Many circumbinary planets have been claimed based on eclipse timing variations in post-common envelope binaries, but most of these claims have been challenged as planetary models often fail to predict future changes in eclipse timing. Other proposed causes, such as the Applegate mechanism, often cannot fully explain the observations either, so the true cause of these variations remains unclear. Some of these proposed planets are listed in the table below.

Circumbinary planets are common in many science fiction stories:

• In David Lindsay's A Voyage to Arcturus, Lindsay imagines that Arcturus is a binary system made up of the stars Branchspell and Alppain, and orbited by the planet Tormance.
• In the Trigun series, the planet orbits a binary star system.
• In the Star Wars series, the planet Tatooine orbits in a close binary system.
• In the series Doctor Who, a binary system with such a planet is featured in The Chase. "Gridlock" also depicts the planet Gallifrey as in a binary system, but possibly in a non-circumbinary orbit.{{cite web|url=http://www.chakoteya.net/DoctorWho/29-3.htm|title=The Doctor Who Transcripts - Gridlock}}
• In the Star Fox series, the planets orbit Lylat and Solar (an M-class red dwarf)
• In the Hitchhiker's Guide to the Galaxy series, the circumbinary planet Magrathea is described as the "most improbable planet that ever existed".
• In Stanislaw Lem's Solaris, the titular planet orbits a binary system of a red and a blue star.

• List of planet types
• Circumtriple planet
• {{Section link|Extrasolar planets in fiction|In multiple star systems}}

{{Notelist}}

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{{Cite journal|last1=Schwamb|first1=Megan E.|last2=Orosz|first2=Jerome A.|last3=Carter|first3=Joshua A.|last4=Welsh|first4=William F.|last5=Fischer|first5=Debra A.|last6=Guillermo Torres|last7=Howard|first7=Andrew W.|last8=Crepp|first8=Justin R.|last9=Keel|first9=William C.|date=2013-01-01|title=Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System|journal=The Astrophysical Journal|language=en|volume=768|issue=2|pages=127|doi=10.1088/0004-637X/768/2/127|issn=0004-637X|bibcode=2013ApJ...768..127S|arxiv = 1210.3612 |s2cid=27456469 }}

{{cite journal | title=Reanalysis of the Gravitational Microlensing Event MACHO-97-BLG-41 Based on Combined Data | last1=Jung | first1=Youn Kil | last2=Han | first2=Cheongho | last3=Gould | first3=Andrew | last4=Maoz | first4=Dan | display-authors=1 | journal=The Astrophysical Journal Letters | volume=768 | issue=1 | at=L7 | date=2013 | arxiv=1303.0952 | bibcode=2013ApJ...768L...7J | doi=10.1088/2041-8205/768/1/L7 | s2cid=118390991 }}

{{cite conference |title=Recent Kepler Results On Circumbinary Planets |last1=Welsh |first1=William F. |last2=Orosz |first2=Jerome A. |last3=Carter |first3=Joshua A. |last4=Fabrycky |first4=Daniel C. |date=April 2014 |book-title=Proceedings of the International Astronomical Union |volume=293 |pages=125–132 |conference=Formation, Detection, and Characterization of Extrasolar Habitable Planets |doi=10.1017/S1743921313012684 |arxiv=1308.6328 |bibcode=2014IAUS..293..125W}}

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{{cite web |last1=Johnson |first1=Michele |last2=Jenkins |first2=Ann |last3=Villard |first3=Ray |last4=Harrington |first4=J.D. |title=Kepler Finds a Very Wobbly Planet |url=http://www.nasa.gov/ames/kepler-finds-a-very-wobbly-planet |date=4 February 2014 |work=NASA |access-date=5 February 2014 }}

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{{cite web | url=https://www.nasa.gov/feature/goddard/2016/new-planet-is-largest-discovered-that-orbits-two-suns | title=New Planet Is Largest Discovered That Orbits Two Suns | publisher=NASA | date=June 13, 2016 | access-date=June 14, 2016 | archive-date=June 16, 2016 | archive-url=https://web.archive.org/web/20160616103534/http://www.nasa.gov/feature/goddard/2016/new-planet-is-largest-discovered-that-orbits-two-suns/ | url-status=dead }}

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{{cite journal | bibcode = 2017MNRAS.468.2932G | title=Evidence for a planetary mass third body orbiting the binary star KIC 5095269 | journal=Monthly Notices of the Royal Astronomical Society | volume=468 | issue=3 | pages=2932–2937 | year=2017 |last1=Getley |first1=A. K. |last2=Carter |first2=B. |last3=King |first3=R. |last4=O'Toole |first4=S. | doi=10.1093/mnras/stx604| doi-access=free |arxiv=1703.03518}}

{{cite journal | bibcode = 2017MNRAS.468L.118J | title=Indication of a massive circumbinary planet orbiting the low-mass X-ray binary MXB 1658-298 | journal=Monthly Notices of the Royal Astronomical Society | volume=468 | issue=1 | page=L118 | year=2017 | last1=Jain |first1=Chetana |last2=Paul |first2=Biswajit |last3=Sharma |first3=Rahul |last4=Jaleel |first4=Abdul |last5=Dutta |first5=Anjan | doi=10.1093/mnrasl/slx039| doi-access=free |arxiv = 1703.04433 }}

{{cite journal |last1=Wu |first1=Ya-Lin |last2=Sheehan |first2=Patrick D. |date=September 2017 |title=An ALMA Dynamical Mass Estimate of the Proposed Planetary-mass Companion FW Tau C |journal=The Astrophysical Journal Letters |volume=846 |issue=2 |pages=L26 |doi=10.3847/2041-8213/aa8771 |arxiv=1708.08122 |bibcode=2017ApJ...846L..26W |doi-access=free }}

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{{cite journal |last1=Janson |first1=Markus |last2=Asensio-Torres |first2=Ruben |display-authors=etal |date=June 2019 |title=The B-Star Exoplanet Abundance Study: a co-moving 16-25 M_Jup companion to the young binary system HIP 79098 |journal=Astronomy & Astrophysics |volume=626 |issue= |pages=A99 |doi=10.1051/0004-6361/201935687 |doi-access=free |arxiv=1906.02787 |bibcode=2019A&A...626A..99J}}

{{cite journal |last1=Socia |first1=Quentin J. |last2=Welsh |first2=William F. |display-authors=etal |date=March 2020 |title=Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing Binary |journal=The Astronomical Journal |volume=159 |issue=3 |pages=94 |doi=10.3847/1538-3881/ab665b |doi-access=free |arxiv=2001.02840 |bibcode=2020AJ....159...94S}}

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{{cite journal |last1=Kostov |first1=Veselin B. |last2=Powell |first2=Brian P. |display-authors=etal |date=December 2021 |title=TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data |journal=The Astronomical Journal |volume=162 |issue=6 |pages=234 |doi=10.3847/1538-3881/ac223a |doi-access=free |arxiv=2105.08614 |bibcode=2021AJ....162..234K}}

{{cite journal |last1=Pulley |first1=D. |last2=Sharp |first2=I. D. |last3=Mallett |first3=J. |last4=von Harrach |first4=S. |date=August 2022 |title=Eclipse timing variations in post-common envelope binaries: Are they a reliable indicator of circumbinary companions? |journal=Monthly Notices of the Royal Astronomical Society |volume=514 |issue=4 |pages=5725–5738 |doi=10.1093/mnras/stac1676 |doi-access=free |arxiv=2206.06919 |bibcode=2022MNRAS.514.5725P}}

{{cite journal |last1=Dupuy |first1=Trent J. |last2=Liu |first2=Michael C. |display-authors=etal |date=February 2023 |title=On the masses, age, and architecture of the VHS J1256-1257AB b system |journal=Monthly Notices of the Royal Astronomical Society |volume=519 |issue=2 |pages=1688–1694 |doi=10.1093/mnras/stac3557 |doi-access=free |arxiv=2208.08448 |bibcode=2023MNRAS.519.1688D}}

{{cite journal |last1=Standing |first1=Matthew R. |last2=Sairam |first2=Lalitha |display-authors=etal |date=June 2023 |title=Radial-velocity discovery of a second planet in the TOI-1338/BEBOP-1 circumbinary system |journal=Nature Astronomy |volume=7 |issue= 6|pages=702–714 |doi=10.1038/s41550-023-01948-4 |arxiv=2301.10794 |bibcode=2023NatAs...7..702S}}

{{cite journal |last1=Goldberg |first1=Max |last2=Fabrycky |first2=Daniel |display-authors=etal |date=November 2023 |title=A 5M_Jup non-transiting coplanar circumbinary planet around Kepler-1660AB |journal=Monthly Notices of the Royal Astronomical Society |volume=525 |issue=3 |pages=4628–4641 |doi=10.1093/mnras/stad2568 |doi-access=free |arxiv=2308.09255 |bibcode=2023MNRAS.525.4628G}}

{{cite journal |last1=Wang |first1=Mu-Tian |last2=Liu |first2=Hui-Gen |date=July 2024 |title=Photo-dynamical Analysis of Circumbinary Multi-planet System TOI-1338: A Fully Coplanar Configuration with a Puffy Planet |journal=The Astronomical Journal |volume=168 |issue=1 |pages=31 |doi=10.3847/1538-3881/ad4a60 |doi-access=free |arxiv=2404.18415 |bibcode=2024AJ....168...31W}}

{{cite journal |last1=Baycroft |first1=Thomas A. |last2=Sairam |first2=Lalitha |last3=Triaud |first3=Amaury H. M. J. |last4=Correia |first4=Alexandre C. M. |date=April 2025 |title=Evidence for a polar circumbinary exoplanet orbiting a pair of eclipsing brown dwarfs |url=https://www.eso.org/public/archives/releases/sciencepapers/eso2508/eso2508a.pdf |journal=Science Advances |volume=11 |issue=16 |pages= eadu0627|doi=10.1126/sciadv.adu0627 |doi-access=free|pmid=40238865 |pmc=12002110 |arxiv=2504.12209 |bibcode=2025SciA...11..627B }}

{{cite arXiv|eprint=2505.13295 |last1=Liu |first1=Pengyu |last2=Kenworthy |first2=Matthew A. |last3=Biller |first3=Beth A. |last4=Wallace |first4=Alex |last5=Stolker |first5=Tomas |last6=Haffert |first6=Sebastiaan |last7=Ginski |first7=Christian |last8=Mamajek |first8=Eric E. |last9=Castro-Ginard |first9=Alfred |last10=Meshkat |first10=Tiffany |last11=Pecaut |first11=Mark J. |last12=Reggiani |first12=Maddalena |last13=Males |first13=Jared R. |last14=Close |first14=Laird M. |last15=Guyon |first15=Olivier |last16=Doty |first16=Isabella |author17=Kyle Van Gorkom |last18=Hedglen |first18=Alex |last19=Kautz |first19=Maggie |last20=Kueny |first20=Jay |last21=Liberman |first21=Joshua |last22=Li |first22=Jialin |last23=Long |first23=Joseph D. |last24=Lumbres |first24=Jennifer |last25=McEwen |first25=Eden |last26=Pearce |first26=Logan |last27=Roberts IV |first27=Roswell R. |last28=Schatz |first28=Lauren |last29=Twitchell |first29=Katie |title=A planetary-mass candidate imaged in the Young Suns Exoplanet Survey |date=2025 |class=astro-ph.EP }}

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• {{cite book|author=Nader Haghighipour|title=Planets in Binary Star Systems|url=https://books.google.com/books?id=kyf7vgv6FSYC|year=2010|publisher=Springer Science & Business Media|isbn=978-90-481-8687-7}}

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Category:Types of planet

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