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{{Other uses|PH-1 (disambiguation){{!}}PH-1}}
{{Other uses|PH-1 (disambiguation){{!}}PH-1}}
{{Short description|Circumbinary Neptunian planet orbiting the Kepler-64 star system}}
{{Infobox planet
{{Infobox planet
| name = PH1b <ref name=PCMag/> / Kepler-64b
| name = PH1b <ref name=PCMag/> / Kepler-64b
| image = PH1Kepler64system.jpg
| image =
| caption = Artistic simulation of the quadruple PH1/Kepler-64 star system, as seen from PH1b ''(foreground)''.
| caption = Artistic simulation of the quadruple PH1/Kepler-64 star system, as seen from PH1b ''(foreground)''.
<!-- DISCOVERY -->
<!-- DISCOVERY -->
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| discovery_site = [[Kepler space telescope]]
| discovery_site = [[Kepler space telescope]]
| discovered = 15 October 2012 <ref name=PlanetHunters/>
| discovered = 15 October 2012 <ref name=PlanetHunters/>
| discovery_method = [[Transit method|Transit]] <ref name=PlanetHunters/>
| discovery_method = [[Transit method|Transit]]<ref name=PlanetHunters/>
<!-- DESIGNATIONS -->
<!-- DESIGNATIONS -->
<!-- ORBITAL -->
<!-- ORBITAL -->
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<!-- PHYS CHARS -->
<!-- PHYS CHARS -->
| mean_radius = {{val|6.18|0.17}}<ref name=arXiv/> {{Earth radius|link=y}}
| mean_radius = {{val|6.18|0.17}}<ref name=arXiv/> {{Earth radius|link=y}}
| mass = 0.08-0.14 <ref name=arXiv/> {{Jupiter mass|link=y}}<br>(20-50 <ref name=arXiv/> {{Earth mass|link=y}})
| mass = 0.08–0.14 <ref name=arXiv/> {{Jupiter mass|link=y}}<br/>(20–50 <ref name=arXiv/> {{Earth mass|link=y}})
| single_temperature = {{convert|481|K|C F}}
| single_temperature = {{convert|481|K|C F}}
<!-- ATMOSPHERE -->
<!-- ATMOSPHERE -->
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}}
}}


'''PH1b''' (standing for "Planet Hunters 1"), or by its NASA designation '''Kepler-64b''',<ref>{{Cite web | url=http://www.nasa.gov/mission_pages/kepler/news/keplerm-20121026.html |title = Kepler Mission Manager Update|date = 2015-04-15}}</ref> is an [[extrasolar planet]] found in a [[circumbinary planet|circumbinary orbit]] in the [[Star system#Quaternary|quadruple star system]] Kepler-64. The planet was discovered by two amateur astronomers from the [[Planet Hunters]] project of [[amateur astronomer]]s using data from the [[Kepler space telescope]] with assistance of a [[Yale University]] team of international [[astronomer]]s. The discovery was announced on 15 October 2012.<ref name=VOA>Voice of America, [http://www.voanews.com/content/new_planet_with_four_suns/1527441.html "Citizen Astronomers Discover Planet with Four Suns"], ''16 October 2012''</ref><ref name=Yahoo>Yahoo News, [http://uk.news.yahoo.com/planet-four-suns-discovered-154014489.html "Planet with four suns discovered"] {{webarchive|url=https://web.archive.org/web/20121018011940/http://uk.news.yahoo.com/planet-four-suns-discovered-154014489.html |date=2012-10-18 }}, '''Press Association''', ''15 October 2012'' (accessed 20 October 2012)</ref> It is the first known [[transiting planet]] in a quadruple star system,<ref name=SpaceRef-2012-10-14/> first known circumbinary planet in a quadruple star system,<ref name=JPL-2012-10-15>NASA JPL, [http://www.jpl.nasa.gov/news/news.php?release=2012-324 "Citizens Discover Four-Star Planet with NASA's Kepler"], '''Whitney Clavin''', ''15 October 2012'' (accessed 20 October 2012)</ref> and the first planet in a quadruple star system found. It was the first confirmed planet discovered by PlanetHunters.org.<ref name=PlanetHunters>PlanetHunters.org, [http://blog.planethunters.org/2012/10/15/ph1-a-planet-in-a-four-star-system/ "PH1 : A planet in a four-star system"], ''15 October 2012'' (accessed 20 October 2012)</ref> An independent and nearly simultaneous detection was also reported from a revision of Kepler space telescope data using a transit detection algorithm.<ref>{{Cite journal|last=Kostov|first=V. B.|last2=McCullough|first2=P. R.|last3=Hinse|first3=T. C.|last4=Tsvetanov|first4=Z. I.|last5=Hébrard|first5=G.|last6=Díaz|first6=R. F.|last7=Deleuil|first7=M.|last8=Valenti|first8=J. A.|date=2013-01-01|title=A Gas Giant Circumbinary Planet Transiting the F Star Primary of the Eclipsing Binary Star KIC 4862625 and the Independent Discovery and Characterization of the Two Transiting Planets in the Kepler-47 System|url=http://stacks.iop.org/0004-637X/770/i=1/a=52|journal=The Astrophysical Journal|language=en|volume=770|issue=1|pages=52|doi=10.1088/0004-637X/770/1/52|issn=0004-637X|arxiv = 1210.3850 |bibcode = 2013ApJ...770...52K }}</ref>
'''PH1b''' (standing for "Planet Hunters 1"), or by its NASA designation '''Kepler-64b''',<ref>{{Cite web | url=http://www.nasa.gov/mission_pages/kepler/news/keplerm-20121026.html |title = Kepler Mission Manager Update|date = 2015-04-15}}</ref> is an [[extrasolar planet]] found in a [[circumbinary planet|circumbinary orbit]] in the [[Star system#Quaternary|quadruple star system]] Kepler-64. The planet was discovered by two amateur astronomers from the [[Planet Hunters]] project of [[amateur astronomer]]s using data from the [[Kepler space telescope]] with assistance of a [[Yale University]] team of international [[astronomer]]s. The discovery was announced on 15 October 2012.<ref name=VOA>{{cite web |website=Voice of America |url=http://www.voanews.com/content/new_planet_with_four_suns/1527441.html |title=Citizen Astronomers Discover Planet with Four Suns |date=16 October 2012 }}</ref><ref name=Yahoo>{{cite web |website=Yahoo News |url=http://uk.news.yahoo.com/planet-four-suns-discovered-154014489.html |title=Planet with four suns discovered |archiveurl=https://web.archive.org/web/20121018011940/http://uk.news.yahoo.com/planet-four-suns-discovered-154014489.html |archive-date=2012-10-18 |author=Press Association |date=15 October 2012 |access-date=20 October 2012 }}</ref> It is the first known [[transiting planet]] in a quadruple star system,<ref name=SpaceRef-2012-10-14/> first known circumbinary planet in a quadruple star system,<ref name=JPL-2012-10-15>{{cite web |website=NASA JPL |url=http://www.jpl.nasa.gov/news/news.php?release=2012-324 |title=Citizens Discover Four-Star Planet with NASA's Kepler |author=Whitney Clavin |date=15 October 2012 |access-date=20 October 2012 }}</ref> and the first planet in a quadruple star system found. It was the first confirmed planet discovered by PlanetHunters.org.<ref name=PlanetHunters>{{cite web |website=PlanetHunters |url=http://blog.planethunters.org/2012/10/15/ph1-a-planet-in-a-four-star-system/ |title=PH1 : A planet in a four-star system |date=15 October 2012 |access-date=20 October 2012 }}</ref> An independent and nearly simultaneous detection was also reported from a revision of Kepler space telescope data using a transit detection algorithm.<ref>{{Cite journal|last1=Kostov|first1=V. B.|last2=McCullough|first2=P. R.|last3=Hinse|first3=T. C.|last4=Tsvetanov|first4=Z. I.|last5=Hébrard|first5=G.|last6=Díaz|first6=R. F.|last7=Deleuil|first7=M.|last8=Valenti|first8=J. A.|date=2013-01-01|title=A Gas Giant Circumbinary Planet Transiting the F Star Primary of the Eclipsing Binary Star KIC 4862625 and the Independent Discovery and Characterization of the Two Transiting Planets in the Kepler-47 System|journal=The Astrophysical Journal|language=en|volume=770|issue=1|pages=52|doi=10.1088/0004-637X/770/1/52|issn=0004-637X|arxiv = 1210.3850 |bibcode = 2013ApJ...770...52K |s2cid=119279690}}</ref>


==Star system==
==Star system==
The [[giant planet]] is [[Neptune]]-sized, about 20-55 [[Earth mass|Earth-masses]] ({{Earth mass}}). It has a radius 6.2 times that of Earth's. The star system is 7200 [[light year]]s<ref name="Gaia">{{Cite journal|last=Gaia Collaboration|date=2018-08-01|title=Gaia Data Release 2 - Summary of the contents and survey properties|journal=Astronomy & Astrophysics|language=en|volume=616|pages=A1|arxiv=1804.09365|doi=10.1051/0004-6361/201833051|issn=0004-6361}}</ref> from Earth.<ref name=arXiv/><ref name=ABCau>ABC News (Australia), [http://www.abc.net.au/news/2012-10-16/astronomers-discover-planet-with-four-suns/4316624 "Astronomers discover planet with four suns"], '''AFP''', ''17 October 2012'' (accessed 20 October 2012)</ref><ref name=Yahoo/><ref name=KSDK>KSDK-TV, [http://www.ksdk.com/news/article/343153/28/Planet-Hunters-discover-new-planet-PH-1 'Planet Hunters' discover new planet, PH-1], '''CNN''', ''15 October 2012'' (accessed 20 October 2012)</ref> The planet orbits a close [[binary star|binary]], with a more distant binary orbiting at a distance, forming the quadruple star system. The star system has the Kepler Input Catalogue name [[KIC 4862625]] as well as the designation [[Kepler-64]]. The close binary (Aa+Ab) that the planet circles has an orbital period of 20 days. They form an [[eclipsing binary]] pair.<ref name=PCMag/> The two stars are (Aa) 1.384 [[solar mass]] ({{Solar mass|link=yes}}) [[F-type main-sequence star]] and (Ab) {{Solar mass|0.336}} [[red dwarf]].<ref>{{Cite journal|last=Martin|first=David V.|date=September 2019|title=The binary mass ratios of circumbinary planet hosts|url=https://ui.adsabs.harvard.edu/abs/2019MNRAS.488.3482M/abstract|journal=MNRAS|language=en|volume=488|issue=3|pages=3482–3491|doi=10.1093/mnras/stz959|issn=0035-8711|via=}}</ref><ref name=arXiv>arXiv. "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System", ''Megan E. Schwamb, Jerome A. Orosz, Joshua A. Carter, William F. Welsh, Debra A. Fischer, Guillermo Torres, Andrew W. Howard, Justin R. Crepp, William C. Keel, Chris J. Lintott, Nathan A. Kaib, Dirk Terrell, Robert Gagliano, Kian J. Jek, Michael Parrish, Arfon M. Smith, Stuart Lynn, Robert J. Simpson, Matthew J. Giguere, Kevin Schawinski'', 2012 October, {{arXiv|1210.3612}} ; {{bibcode|2012arXiv1210.3612S}} ;</ref><ref name=ABCau/><ref name=SpaceRef-2012-10-14>SpaceRef, [http://www.spaceref.com/news/viewsr.html?pid=42334 "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System"], ''14 October 2012'' (accessed 20 October 2012)</ref> The planet orbits this binary pair in a 138.3-day orbit. The binary pairs have a separation of 1000 [[astronomical unit|AU]]s<!-- likely ~1500 au, using the 0.7" in the paper and the Gaia distance of about 2200 parsec. Distance was underestimated. -->.<ref name=PCMag/> A photometric-dynamical model was used to model the [[planetary system]] of the close binary pair. The distant binary (Ba+Bb) have a pair separation of 60 AU. The two stars are (Ba) {{Solar mass|0.99}} [[G-type main-sequence star]] and (Bb) {{Solar mass|0.51}} red dwarf. The quadruple star system has an estimated age of 2 gigayears.<ref name=arXiv/> The system is located at [[right ascension]] {{RA|19|52|51.624}} [[declination]] {{DEC|+39|57|18.36}}, so also has a [[2MASS]] catalogue entry of ''[[2MASS 19525162+3957183]]''<ref name=KeplerCatalogue-KIC4862625>Kepler Catalogue, KIC 4862625 <!--
The [[giant planet]] is [[Neptune]]-sized, about 20-55 [[Earth mass|Earth-masses]] ({{Earth mass}}). It has a radius 6.2 times that of Earth. The star system is 7200 [[light year]]s<ref name="Gaia">{{Cite Gaia DR2}}</ref> from Earth.<ref name=arXiv/><ref name=ABCau>{{cite web |website=ABC News (Australia) |url=http://www.abc.net.au/news/2012-10-16/astronomers-discover-planet-with-four-suns/4316624 |title=Astronomers discover planet with four suns |author=AFP |date=17 October 2012 |access-date=20 October 2012 }}</ref><ref name=Yahoo/><ref name=KSDK>{{cite web |website=KSDK-TV |url=http://www.ksdk.com/news/article/343153/28/Planet-Hunters-discover-new-planet-PH-1 |title=Planet Hunters' discover new planet, PH-1 |author=CNN |date=15 October 2012 |access-date=20 October 2012 |archive-date=27 December 2012 |archive-url=https://archive.today/20121227182847/http://www.ksdk.com/news/article/343153/28/Planet-Hunters-discover-new-planet-PH-1 |url-status=dead }}</ref> The planet orbits a close [[binary star|binary]], with a more distant binary orbiting at a distance, forming the quadruple star system. The star system has the Kepler Input Catalogue name [[KIC 4862625]] as well as the designation [[Kepler-64]]. The close binary (Aa+Ab) that the planet circles has an orbital period of 20 days. They form an [[eclipsing binary]] pair.<ref name=PCMag/> The two stars are (Aa) 1.384 [[solar mass]] ({{Solar mass|link=yes}}) [[F-type main-sequence star]] and (Ab) {{Solar mass|0.336}} [[red dwarf]].<ref>{{Cite journal|last=Martin|first=David V.|date=September 2019|title=The binary mass ratios of circumbinary planet hosts|journal=MNRAS|language=en|volume=488|issue=3|pages=3482–3491|doi=10.1093/mnras/stz959|issn=0035-8711|arxiv=1904.04832|bibcode=2019MNRAS.488.3482M|s2cid=119210045}}</ref><ref name=arXiv>{{cite journal |arxiv=1210.3612 |doi=10.1088/0004-637X/768/2/127 |title=Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System |year=2013 |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=Torres |first6=Guillermo |last7=Howard |first7=Andrew W. |last8=Crepp |first8=Justin R. |last9=Keel |first9=William C. |last10=Lintott |first10=Chris J. |last11=Kaib |first11=Nathan A. |last12=Terrell |first12=Dirk |last13=Gagliano |first13=Robert |last14=Jek |first14=Kian J. |last15=Parrish |first15=Michael |last16=Smith |first16=Arfon M. |last17=Lynn |first17=Stuart |last18=Simpson |first18=Robert J. |last19=Giguere |first19=Matthew J. |last20=Schawinski |first20=Kevin |journal=The Astrophysical Journal |volume=768 |issue=2 |page=127 |bibcode=2013ApJ...768..127S |s2cid=27456469 }}</ref><ref name=ABCau/><ref name=SpaceRef-2012-10-14>{{cite web |website=SpaceRef |url=http://www.spaceref.com/news/viewsr.html?pid=42334 |title=Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System |date=14 October 2012 |access-date=20 October 2012 }}</ref> The planet orbits this binary pair in a 138.3-day orbit. The binary pairs have a separation of 1000 [[astronomical unit|AU]]s<!-- likely ~1500 au, using the 0.7" in the paper and the Gaia distance of about 2200 parsec. Distance was underestimated. -->.<ref name=PCMag/> A photometric-dynamical model was used to model the [[planetary system]] of the close binary pair. The distant binary (Ba+Bb) have a pair separation of 60 AU. The two stars are (Ba) {{Solar mass|0.99}} [[G-type main-sequence star]] and (Bb) {{Solar mass|0.51}} red dwarf. The quadruple star system has an estimated age of two billion years (2 gigayears).<ref name=arXiv/> The system is located at [[right ascension]] {{RA|19|52|51.624}} [[declination]] {{DEC|+39|57|18.36}}, so also has a [[2MASS]] catalogue entry of ''[[2MASS 19525162+3957183]]''<ref name=KeplerCatalogue-KIC4862625>Kepler Catalogue, KIC 4862625 <!--
Kepler query:
Kepler query:
SELECT top 101 ktc_kepler_id, ktc_investigation_id, sci_data_set_name, sci_data_quarter, sci_ra, sci_dec, ktc_target_type, sci_archive_class, refnum, sci_start_time, sci_end_time, sci_release_date, kic_rmag, twomass_jmag, kic_kepmag, twomass_2mass_id, twomass_conflictflag, kic_teff, kic_logg, kic_feh, kic_ebminusv, kic_radius, kic_pmtotal, kic_grcolor, condition_flag
SELECT top 101 ktc_kepler_id, ktc_investigation_id, sci_data_set_name, sci_data_quarter, sci_ra, sci_dec, ktc_target_type, sci_archive_class, refnum, sci_start_time, sci_end_time, sci_release_date, kic_rmag, twomass_jmag, kic_kepmag, twomass_2mass_id, twomass_conflictflag, kic_teff, kic_logg, kic_feh, kic_ebminusv, kic_radius, kic_pmtotal, kic_grcolor, condition_flag
Line 37: Line 38:
==Discovery==
==Discovery==
[[File:LG-4862625-LC-transits.png|thumbnail|left|Light curve signaling the discovery of PH1, showing the first three transits of Kepler-64 (KIC 4862625)]]
[[File:LG-4862625-LC-transits.png|thumbnail|left|Light curve signaling the discovery of PH1, showing the first three transits of Kepler-64 (KIC 4862625)]]
Kian Jek, from San Francisco, and Robert Gagliano, from Cottonwood, Arizona, spotted the signature of the planet in the Kepler data, and it was reported through the PlanetHunters.org program run by Dr. [[Chris Lintott]], from Oxford University.<ref name=Yahoo/> Kian Jek first spotted a light dip indicative of a transit in May 2011. JKD reported a second. Robert Gagliano performed a systematic search, and confirmed the second dip, and found a third, in February 2012. Using this, Kian predicted another transit, and found it. The planet was subsequently detected by eclipsing binary timing variation method.<ref name=PCMag>PC Magazine, [https://www.pcmag.com/article2/0,2817,2411006,00.asp "Citizen Scientists Discover Planet in Quadruple Star System"], '''Tony Hoffman''', ''16 October 2012'' (accessed 20 October 2012)</ref> At the time of discovery, it was the sixth known circumbinary planet.
Kian Jin Jek (Chinese: 易建仁, son of [[Jek Yeun Thong]]), from San Francisco, and Robert Gagliano, from Cottonwood, Arizona, spotted the signature of the planet in the Kepler data, and it was reported through the PlanetHunters.org program run by Dr. [[Chris Lintott]], from Oxford University.<ref name=Yahoo/> Kian Jek first spotted a light dip indicative of a transit in May 2011. JKD reported a second. Robert Gagliano performed a systematic search, and confirmed the second dip, and found a third, in February 2012. Using this, Kian predicted another transit, and found it. The planet was subsequently detected by eclipsing binary timing variation method.<ref name=PCMag>{{cite web |website=PC Magazine |url=https://www.pcmag.com/article2/0,2817,2411006,00.asp |title=Citizen Scientists Discover Planet in Quadruple Star System |author=Tony Hoffman |date=16 October 2012 |access-date=20 October 2012 }}</ref> At the time of discovery, it was the sixth known circumbinary planet.


== Role as a benchmark system ==
== Role as a benchmark system ==
The planet PH1b and were used as a benchmark system for automated detection algorithms. As a benchmark system PH1 is used to improve the algorithm and to demonstrate improvement in the detection of circumbinary planets.<ref>{{Cite journal|last=Windemuth|first=Diana|last2=Agol|first2=Eric|last3=Carter|first3=Josh|last4=Ford|first4=Eric B.|last5=Haghighipour|first5=Nader|last6=Orosz|first6=Jerome A.|last7=Welsh|first7=William F.|date=November 2019|title=An automated method to detect transiting circumbinary planets|url=https://ui.adsabs.harvard.edu/abs/2019MNRAS.490.1313W/abstract|journal=MNRAS|language=en|volume=490|issue=1|pages=1313–1324|doi=10.1093/mnras/stz2637|issn=0035-8711|via=}}</ref>
The planet PH1b and were used as a benchmark system for automated detection algorithms. As a benchmark system PH1 is used to improve the algorithm and to demonstrate improvement in the detection of circumbinary planets.<ref>{{Cite journal|last1=Windemuth|first1=Diana|last2=Agol|first2=Eric|last3=Carter|first3=Josh|last4=Ford|first4=Eric B.|last5=Haghighipour|first5=Nader|last6=Orosz|first6=Jerome A.|last7=Welsh|first7=William F.|date=November 2019|title=An automated method to detect transiting circumbinary planets|journal=MNRAS|language=en|volume=490|issue=1|pages=1313–1324|doi=10.1093/mnras/stz2637|issn=0035-8711|arxiv=1909.07443|bibcode=2019MNRAS.490.1313W|s2cid=202583681}}</ref>


==See also==
==See also==
Line 53: Line 54:
* '''Discovery Paper''': arXiv. "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System", ''Megan E. Schwamb, Jerome A. Orosz, Joshua A. Carter, William F. Welsh, Debra A. Fischer, Guillermo Torres, Andrew W. Howard, Justin R. Crepp, William C. Keel, Chris J. Lintott, Nathan A. Kaib, Dirk Terrell, Robert Gagliano, Kian J. Jek, Michael Parrish, Arfon M. Smith, Stuart Lynn, Robert J. Simpson, Matthew J. Giguere, Kevin Schawinski'', 2012 October, {{arXiv|1210.3612}} ; {{bibcode|2012arXiv1210.3612S}} ;
* '''Discovery Paper''': arXiv. "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System", ''Megan E. Schwamb, Jerome A. Orosz, Joshua A. Carter, William F. Welsh, Debra A. Fischer, Guillermo Torres, Andrew W. Howard, Justin R. Crepp, William C. Keel, Chris J. Lintott, Nathan A. Kaib, Dirk Terrell, Robert Gagliano, Kian J. Jek, Michael Parrish, Arfon M. Smith, Stuart Lynn, Robert J. Simpson, Matthew J. Giguere, Kevin Schawinski'', 2012 October, {{arXiv|1210.3612}} ; {{bibcode|2012arXiv1210.3612S}} ;



==External links==
* NASA JPL, [http://www.jpl.nasa.gov/news/news.php?release=2012-324 "Citizens Discover Four-Star Planet with NASA's Kepler"], '''Whitney Clavin''', ''15 October 2012'' (accessed 20 October 2012)


{{2012 in space}}
{{2012 in space}}

Latest revision as of 05:03, 16 September 2023

For other uses, see PH-1.
PH1b [1] / Kepler-64b
Discovery
Discovered byPlanet Hunters
Discovery siteKepler space telescope
Discovery date15 October 2012 [2]
Transit[2]
Orbital characteristics
0.634 ± 0.011 [3] AU
138.506+0.107
−0.092[3] d
Semi-amplitude(20.69±0.31)×103[3]
StarKepler-64 / PH1 [1]
Physical characteristics
Mean radius
6.18±0.17[3] R🜨
Mass0.08–0.14 [3] MJ
(20–50 [3] ME)
Temperature481 K (208 °C; 406 °F)

PH1b (standing for "Planet Hunters 1"), or by its NASA designation Kepler-64b,[4] is an extrasolar planet found in a circumbinary orbit in the quadruple star system Kepler-64. The planet was discovered by two amateur astronomers from the Planet Hunters project of amateur astronomers using data from the Kepler space telescope with assistance of a Yale University team of international astronomers. The discovery was announced on 15 October 2012.[5][6] It is the first known transiting planet in a quadruple star system,[7] first known circumbinary planet in a quadruple star system,[8] and the first planet in a quadruple star system found. It was the first confirmed planet discovered by PlanetHunters.org.[2] An independent and nearly simultaneous detection was also reported from a revision of Kepler space telescope data using a transit detection algorithm.[9]

Star system[edit]

The giant planet is Neptune-sized, about 20-55 Earth-masses (ME). It has a radius 6.2 times that of Earth. The star system is 7200 light years[10] from Earth.[3][11][6][12] The planet orbits a close binary, with a more distant binary orbiting at a distance, forming the quadruple star system. The star system has the Kepler Input Catalogue name KIC 4862625 as well as the designation Kepler-64. The close binary (Aa+Ab) that the planet circles has an orbital period of 20 days. They form an eclipsing binary pair.[1] The two stars are (Aa) 1.384 solar mass (M☉) F-type main-sequence star and (Ab) 0.336 M☉ red dwarf.[13][3][11][7] The planet orbits this binary pair in a 138.3-day orbit. The binary pairs have a separation of 1000 AUs.[1] A photometric-dynamical model was used to model the planetary system of the close binary pair. The distant binary (Ba+Bb) have a pair separation of 60 AU. The two stars are (Ba) 0.99 M☉ G-type main-sequence star and (Bb) 0.51 M☉ red dwarf. The quadruple star system has an estimated age of two billion years (2 gigayears).[3] The system is located at right ascension 19h 52m 51.624s declination +39° 57′ 18.36″, so also has a 2MASS catalogue entry of 2MASS 19525162+3957183[14]

Discovery[edit]

Light curve signaling the discovery of PH1, showing the first three transits of Kepler-64 (KIC 4862625)

Kian Jin Jek (Chinese: 易建仁, son of Jek Yeun Thong), from San Francisco, and Robert Gagliano, from Cottonwood, Arizona, spotted the signature of the planet in the Kepler data, and it was reported through the PlanetHunters.org program run by Dr. Chris Lintott, from Oxford University.[6] Kian Jek first spotted a light dip indicative of a transit in May 2011. JKD reported a second. Robert Gagliano performed a systematic search, and confirmed the second dip, and found a third, in February 2012. Using this, Kian predicted another transit, and found it. The planet was subsequently detected by eclipsing binary timing variation method.[1] At the time of discovery, it was the sixth known circumbinary planet.

Role as a benchmark system[edit]

The planet PH1b and were used as a benchmark system for automated detection algorithms. As a benchmark system PH1 is used to improve the algorithm and to demonstrate improvement in the detection of circumbinary planets.[15]

See also[edit]

References[edit]

  1. ^ a b c d e Tony Hoffman (16 October 2012). "Citizen Scientists Discover Planet in Quadruple Star System". PC Magazine. Retrieved 20 October 2012.
  2. ^ a b c "PH1 : A planet in a four-star system". PlanetHunters. 15 October 2012. Retrieved 20 October 2012.
  3. ^ a b c d e f g h i Schwamb, Megan E.; Orosz, Jerome A.; Carter, Joshua A.; Welsh, William F.; Fischer, Debra A.; Torres, Guillermo; Howard, Andrew W.; Crepp, Justin R.; Keel, William C.; Lintott, Chris J.; Kaib, Nathan A.; Terrell, Dirk; Gagliano, Robert; Jek, Kian J.; Parrish, Michael; Smith, Arfon M.; Lynn, Stuart; Simpson, Robert J.; Giguere, Matthew J.; Schawinski, Kevin (2013). "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System". The Astrophysical Journal. 768 (2): 127. arXiv:1210.3612. Bibcode:2013ApJ...768..127S. doi:10.1088/0004-637X/768/2/127. S2CID 27456469.
  4. ^ "Kepler Mission Manager Update". 2015-04-15.
  5. ^ "Citizen Astronomers Discover Planet with Four Suns". Voice of America. 16 October 2012.
  6. ^ a b c Press Association (15 October 2012). "Planet with four suns discovered". Yahoo News. Archived from the original on 2012-10-18. Retrieved 20 October 2012.
  7. ^ a b "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System". SpaceRef. 14 October 2012. Retrieved 20 October 2012.
  8. ^ Whitney Clavin (15 October 2012). "Citizens Discover Four-Star Planet with NASA's Kepler". NASA JPL. Retrieved 20 October 2012.
  9. ^ Kostov, V. B.; McCullough, P. R.; Hinse, T. C.; Tsvetanov, Z. I.; Hébrard, G.; Díaz, R. F.; Deleuil, M.; Valenti, J. A. (2013-01-01). "A Gas Giant Circumbinary Planet Transiting the F Star Primary of the Eclipsing Binary Star KIC 4862625 and the Independent Discovery and Characterization of the Two Transiting Planets in the Kepler-47 System". The Astrophysical Journal. 770 (1): 52. arXiv:1210.3850. Bibcode:2013ApJ...770...52K. doi:10.1088/0004-637X/770/1/52. ISSN 0004-637X. S2CID 119279690.
  10. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  11. ^ a b AFP (17 October 2012). "Astronomers discover planet with four suns". ABC News (Australia). Retrieved 20 October 2012.
  12. ^ CNN (15 October 2012). "Planet Hunters' discover new planet, PH-1". KSDK-TV. Archived from the original on 27 December 2012. Retrieved 20 October 2012. {{cite web}}: |author= has generic name (help)
  13. ^ Martin, David V. (September 2019). "The binary mass ratios of circumbinary planet hosts". MNRAS. 488 (3): 3482–3491. arXiv:1904.04832. Bibcode:2019MNRAS.488.3482M. doi:10.1093/mnras/stz959. ISSN 0035-8711. S2CID 119210045.
  14. ^ Kepler Catalogue, KIC 4862625
  15. ^ Windemuth, Diana; Agol, Eric; Carter, Josh; Ford, Eric B.; Haghighipour, Nader; Orosz, Jerome A.; Welsh, William F. (November 2019). "An automated method to detect transiting circumbinary planets". MNRAS. 490 (1): 1313–1324. arXiv:1909.07443. Bibcode:2019MNRAS.490.1313W. doi:10.1093/mnras/stz2637. ISSN 0035-8711. S2CID 202583681.

Further reading[edit]

  • Discovery Announcement: PlanetHunters.org, "PH1 : A planet in a four-star system", 15 October 2012 (accessed 20 October 2012)
  • Discovery Paper: arXiv. "Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System", Megan E. Schwamb, Jerome A. Orosz, Joshua A. Carter, William F. Welsh, Debra A. Fischer, Guillermo Torres, Andrew W. Howard, Justin R. Crepp, William C. Keel, Chris J. Lintott, Nathan A. Kaib, Dirk Terrell, Robert Gagliano, Kian J. Jek, Michael Parrish, Arfon M. Smith, Stuart Lynn, Robert J. Simpson, Matthew J. Giguere, Kevin Schawinski, 2012 October, arXiv:1210.3612 ; Bibcode:2012arXiv1210.3612S ;


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