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{{Short description|Star located in the constellation Lyra}}
{{good article}}
{{good article}}
{{Starbox begin
{{Starbox begin
| name=Kepler-9
| name = Kepler-9
}}
}}
{{Starbox image
{{Starbox image
| image = [[File:Artists impression Kepler-9.jpg|250px]]
| image = [[File:Kepler-9 Worlds on the Edge.jpg|250px]]
| caption = An artist's impression of Kepler-9, including planets [[Kepler-9b]] and [[Kepler-9c|c]]
| caption = An artist's impression of Kepler-9, including planets [[Kepler-9b]] and [[Kepler-9c|c]]
}}
}}
{{Starbox observe
{{Starbox observe
| constell= [[Lyra]]
| constell = [[Lyra]]<ref name="Roman1987"/>
| epoch=J2000
| epoch = J2000
| ra= {{RA|19|2|17.76}}
| ra = {{RA|19|2|17.7544}}<ref name="Gaia DR3"/>
| dec= {{DEC|+38|24|3.2}}
| dec = {{DEC|+38|24|03.177}}<ref name="Gaia DR3"/>
| appmag_v = 13.9<ref name="EPE"/>
| appmag_v= 13.9 <ref>{{cite web |url=http://exoplanet.eu/star.php?st=Kepler-9 |title=Notes for star Kepler-9 |date=2010 |work= |publisher=Extrasolar Planets Encyclopaedia |accessdate=6 February 2011}}</ref>
}}
}}
{{Starbox astrometry
{{Starbox astrometry
| prop_mo_ra = {{val|2.472|(13)}}
| dist_pc = 650<ref name="Torres2010">{{cite journal |date=2010|author=Guillermo Torres |display-authors=etal|title=Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for KOI-377, and strong evidence for a super-Earth-size planet in a multiple system |doi=10.1088/0004-637X/727/1/24 |journal=The Astrophysical Journal |volume=727 |pages=24 |issue=24|arxiv=1008.4393|bibcode = 2011ApJ...727...24T }}</ref>
| prop_mo_dec = {{val|−14.691|(15)}}
| pm_footnote = <ref name="Gaia DR3"/>
| parallax = 1.5823
| p_error = 0.0120
| parallax_footnote = <ref name="Gaia DR3"/>
}}
}}
{{Starbox character
{{Starbox character
| class=G2V
| class = G2V
}}
}}
{{Starbox detail
{{Starbox detail
| mass = 1.07<ref name="Torres2010"/>
| source = <ref name="Borsato2019"/>
| mass = {{val|1.022|0.029|0.039}}
| radius= 1.02<ref name="Torres2010"/>
| radius = {{val|0.958|0.020}}
| age_gyr=~1<ref name="Torres2010"/>
| gravity = {{val|4.49|0.02|0.03}}
| temperature=5777 ± 61<ref name="Torres2010"/>
| temperature = {{val|5774|60}}
| gravity=4.49 ± 0.09<ref name="Torres2010"/>
| metal_fe = {{val|+0.05|0.07}}
| metal=<nowiki>[Fe/H]</nowiki> = +0.12 ± 0.04<ref name="Torres2010"/>
| rotation = {{val|16.746|0.077|s=&nbsp;days}}<ref name="McQuillan2013"/>
| rotational_velocity = {{val|2.74|0.40}}<ref name="Wang2018"/>
| age_gyr = {{val|2.0|2.0|1.3}}
}}
}}
{{Starbox catalog |
{{Starbox catalog
| names = {{odlist | 2MASS=J19021775+3824032 | KIC=3323887 | KOI=377 }}<ref name="Simbad"/>
names={{KIC|3323887}}, [[Kepler Object of Interest|KOI]] 377
}}
{{Starbox reference
| Simbad = Kepler-9
| KIC = 3323887
}}
}}
{{Starbox end}}
{{Starbox end}}


'''Kepler-9''' is a [[Solar analog|sunlike]] [[star]] in the [[constellation]] [[Lyra]]. Its [[planetary system]], discovered by the [[Kepler Mission]] in 2010 was the first detected with the [[transit method]] found to contain multiple planets.
'''Kepler-9''' is a [[Solar analog|sunlike]] [[star]] in the [[constellation]] [[Lyra]]. Its [[planetary system]], discovered by the [[Kepler Mission]] in 2010 was the first detected with the [[transit method]] found to contain multiple [[planets]].


==Nomenclature and history==
==Nomenclature and history==
Kepler-9 was named for the [[Kepler (spacecraft)|Kepler Mission]], a project headed by [[NASA]] that was designed to search for [[terrestrial planet|Earth-like]] planets.<ref name="Mission overview"/>


In June 2010, some 43 days after Kepler came online, its operating scientists submitted a list of over 700 exoplanet candidates for review. Of those, five were originally suspected to have more than one planet. Kepler-9 was one of the multiplanetary systems; it was identified as such when scientists noticed significant variations in the time intervals at which Kepler-9 was transited.<ref name="JPL2714"/> Kepler-9 holds the first multiplanetary system discovered using the [[transit method]]. It is also the first planetary system where transiting planets were confirmed through transit timing variations method, allowing to calculate the masses of planets.<ref>{{cite web |url=http://www.universetoday.com/72104/kepler-discovers-multi-planet-system/ |title=Kepler Discovers Multi-Planet System |author=Nancy Atkinson |date=26 August 2010 |publisher=Universe Today |access-date=13 January 2011}}</ref> The discovery of the planets was announced on August 26, 2010.<ref name="JPL2714"/>
Kepler-9 was named for the [[Kepler (spacecraft)|Kepler Mission]], a project headed by [[NASA]] that was designed to search for [[terrestrial planet|Earth-like]] planets.<ref>{{cite web |url=http://kepler.nasa.gov/Mission/QuickGuide/ |title=Kepler: About the Mission |date=2011 |work=Kepler Mission |publisher=NASA |accessdate=13 January 2011}}</ref> Unlike stars such as [[Aldebaran]] or [[Sirius]], Kepler-9 does not have a colloquial name.


==Characteristics==
In June 2010, some 43 days after Kepler came online, its operating scientists submitted a list of over 700 exoplanet candidates for review. Of those, five were originally suspected to have more than one planet. Kepler-9 was one of the multiplanetary systems; it was identified as such when scientists noticed significant variations in the time intervals at which Kepler-9 was transited.<ref>{{cite web |url=http://www.jpl.nasa.gov/news/news.cfm?release=2010-279 |title=NASA's Kepler Mission Discovers Two Planets Transiting Same Star |date=26 August 2010 |work=[[NASA]] [[Jet Propulsion Laboratory]] |publisher=NASA |accessdate=13 January 2011}}</ref> Kepler-9 holds the first multiplanetary system discovered using the [[transit method]]. It is also the first planetary system where transiting planets were confirmed through transit timing variations method, allowing to calculate the masses of planets.<ref>{{cite web |url=http://www.universetoday.com/72104/kepler-discovers-multi-planet-system/ |title=Kepler Discovers Multi-Planet System |author=Nancy Atkinson |date=26 August 2010 |publisher=Universe Today |accessdate=13 January 2011}}</ref> The discovery of the planets was announced on August 26, 2010.<ref name="datatable"/>
Kepler-9 is located in the constellation Lyra that lies some 632 [[parsec]]s away from Earth. With a mass of {{Solar mass|link=y|1.07}} and a radius of {{Solar radius|link=y|1.02}}, Kepler-9 is almost exactly the same size and width of the Sun, being only 7% more massive and 2% wider. Kepler-9 has an [[effective temperature]] of 5777 (± 61) [[Kelvin scale|K]], as compared to the Sun's at 5778 K,<ref name=Sunshine>{{cite web | url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html | title=Sun Fact Sheet | author=David Williams | date=1 September 2004 | work=[[Goddard Space Flight Center]] | publisher=[[NASA]] | access-date=20 March 2011}}</ref> and is approximately 32% more [[metallicity|metal-rich]] (in terms of iron) than the Sun. Kepler-9 is younger than the Sun, and is estimated to be one billion years old.<ref name="Torres2011"/>


==Planetary system==
== Characteristics ==
Kepler-9 is located in the constellation Lyra that lies some 650 [[parsec]]s away from Earth. With a mass of {{Solar mass|link=y|1.07}} and a radius of {{Solar radius|link=y|1.02}}, Kepler-9 is almost exactly the same size and width of the Sun, being only 7% more massive and 2% wider. Kepler-9 has an [[effective temperature]] of 5777 (± 61) [[Kelvin scale|K]], as compared to the Sun's at 5778 K,<ref name=Sunshine>{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html |title=Sun Fact Sheet |author=David Williams |date=1 September 2004 |work=[[Goddard Space Flight Center]] |publisher=[[NASA]] |accessdate=20 March 2011}}</ref> and is approximately 32% more [[metallicity|metal-rich]] (in terms of iron) than the Sun. Kepler-9 is younger than the Sun, and is estimated to be one billion years old.<ref name="Torres2011">{{cite journal |last1=Torres |first1=Guillermo |last2=Fressin |first2=François |date=2011 |title=Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple system |journal=Astrophysical Journal |volume=727 |issue=24 |doi=10.1088/0004-637X/727/1/24 |url=http://exoplanet.eu/papers/Kepler-9-d.pdf |accessdate=20 March 2011 |bibcode=2011ApJ...727...24T|arxiv = 1008.4393 }}</ref>

== Planetary system ==
[[File:kepler9bcdlightcurves-full.jpg|thumb|250px|Light curves of the transiting planets of Kepler-9.]]
[[File:kepler9bcdlightcurves-full.jpg|thumb|250px|Light curves of the transiting planets of Kepler-9.]]
There are three confirmed [[extrasolar planet|planets]], all in direct orbit. The outer two planets, [[Kepler-9b]] (the inner one) and [[Kepler-9c]] (the outer one), are low density gas giants that are respectively 25% and 17% the mass of Jupiter and around 80% the radius of Jupiter. Both planets have a density less than that of water, similar to [[Saturn]]. The innermost planet, [[Kepler-9d]], is a [[super-Earth]] with a radius that is 1.64 [[Earth radius|times that of Earth]],<ref>http://www.kepler.nasa.gov/Mission/discoveries/</ref> orbiting the star every 1.6 days. It is estimated that there is a 0.59% chance that the discoveries are false.<ref name="Torres2010"/>
There are three confirmed [[extrasolar planet|planets]], all in direct orbit. The outer two planets, [[Kepler-9b]] (the inner one) and [[Kepler-9c]] (the outer one), are low-density gas giants that are respectively 25% and 17% the mass of Jupiter and around 80% the radius of Jupiter. Both planets have a density less than that of water, similar to [[Saturn]]. The innermost planet, [[Kepler-9d]], is a [[super-Earth]] with a radius that is 1.64 [[Earth radius|times that of Earth]],<ref name="Freudenthal2018"/><ref name="Torres2011"/> orbiting the star every 1.6 days. It is estimated that there is a 0.59% chance that the discoveries are false.<ref name="Torres2011"/>


From Kepler-9d (closest to star) to Kepler-9b (second from star), the ratio of their orbits is 1:12. However, the ratio of the orbits of the two outer planets is 1:2, a relationship known as a [[orbital resonance|mean motion resonance]]. Kepler-9b and Kepler-9c are the first transiting planets detected in such an orbital configuration.<ref name="Holman2010">{{Cite journal |author=Matthew J. Holman |display-authors=etal|date=2010 |title=Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations |journal=[[Science (journal)|Science]] |volume= 330|issue= 6000|doi=10.1126/science.1195778 |pages=51–54 |bibcode = 2010Sci...330...51H |pmid=20798283}}</ref> The resonance causes the orbital speeds of each planet to change, and thus causes the transit times of the two planets to oscillate. The period of Kepler-9b is increasing by 4 minutes per orbit, while that of Kepler-9c is decreasing by 39 minutes per orbit. These orbital changes allowed the masses of the planets (a parameter not normally obtainable via the transit method) to be estimated using a dynamical model. The mass estimates were further refined using [[Doppler spectroscopy|radial velocity measurements]] obtained with the [[High Resolution Echelle Spectrometer|HIRES]] instrument of the [[W. M. Keck Observatory|Keck 1 telescope]].<ref name="Holman2010"/><ref name = "Alexander">{{cite web
From Kepler-9d (closest to star) to Kepler-9b (second from star), the ratio of their orbits is 1:12. However, the ratio of the orbits of the two outer planets is 1:2, a relationship known as a [[orbital resonance|mean motion resonance]]. Kepler-9b and Kepler-9c are the first transiting planets detected in such an orbital configuration.<ref name="Holman2010"/> The resonance causes the orbital speeds of each planet to change, and thus causes the transit times of the two planets to oscillate. The period of Kepler-9b is increasing by 4 minutes per orbit, while that of Kepler-9c is decreasing by 39 minutes per orbit. These orbital changes allowed the masses of the planets (a parameter not normally obtainable via the transit method) to be estimated using a dynamical model. The mass estimates were further refined using [[Doppler spectroscopy|radial velocity measurements]] obtained with the [[High Resolution Echelle Spectrometer|HIRES]] instrument of the [[W. M. Keck Observatory|Keck 1 telescope]].<ref name="Holman2010"/><ref name="Alexander">{{cite web
| last = Alexander | first = Amir
|last=Alexander
|first=Amir
| title = From the Ground and from Space, New Planetary Systems Unveiled
|title=From the Ground and from Space, New Planetary Systems Unveiled
| work = [http://www.planetary.org/home/ Planetary Society web site]
| publisher = [[The Planetary Society]] | date = 2010-08-27
|work=Planetary Society web site
|publisher=[[The Planetary Society]]
| url = http://www.planetary.org/news/2010/0827_From_the_Ground_and_from_Space_New.html
| accessdate = 2010-08-27}}</ref>
|date=2010-08-27
|url=http://www.planetary.org/news/2010/0827_From_the_Ground_and_from_Space_New.html
|access-date=2010-08-27
|url-status=dead
|archive-url=https://web.archive.org/web/20100901135134/http://www.planetary.org/news/2010/0827_From_the_Ground_and_from_Space_New.html
|archive-date=2010-09-01
}}</ref>


Kepler-9b and 9c are thought to have formed beyond the "[[Frost line (astrophysics)|frost line]]". They are then thought to have migrated inward due to interactions with the remains of the [[protoplanetary disk]]. They would have been captured into orbital resonance during this migration.<ref name="Holman2010"/>
Kepler-9b and 9c are thought to have formed beyond the "[[Frost line (astrophysics)|frost line]]". They are then thought to have migrated inward due to interactions with the remains of the [[protoplanetary disk]]. They would have been captured into orbital resonance during this migration.<ref name="Holman2010"/>


In 2021, it was found the orbital plane of Kepler-9b and Kepler-9c are slowly changing, likely under the gravitational influence of the additional giant planet.<ref>{{citation|arxiv=2105.04318|year=2021|title=Systematic search for long-term transit duration changes in Kepler transiting planets|doi=10.1093/mnras/stab1359|last1=Shahaf|first1=Sahar|last2=Mazeh|first2=Tsevi|last3=Zucker|first3=Shay|last4=Fabrycky|first4=Daniel|journal=Monthly Notices of the Royal Astronomical Society|volume=505 |pages=1293–1310 |doi-access=free |bibcode=2021MNRAS.505.1293S }}</ref>
{{OrbitboxPlanet begin|table_ref=<ref name="datatable">
{{OrbitboxPlanet begin
{{cite web |url=http://www.nasa.gov/mission_pages/kepler/news/two_planet_orbit.html |title=NASA's Kepler Mission Discovers Two Planets Transiting the Same Star |date=2010-08-26 |publisher=NASA|accessdate=2010-08-26}}</ref>}}
| table_ref = <ref name="Freudenthal2018"/><ref name="Torres2011"/>
}}
{{OrbitboxPlanet
{{OrbitboxPlanet
| exoplanet = [[Kepler-9d|d]]
| exoplanet = [[Kepler-9d|d]]
| mass_earth =
| mass_earth = 7.0{{failed verification|date=September 2012}}{{dubious|date=September 2012}}
| semimajor = {{val|0.02730|0.00042|0.00043}}
| radius_earth = 1.60
| period = 1.59
| period = {{val|1.592851|0.000045}}
| semimajor = 0.027
| eccentricity = 0
| eccentricity = 0
| inclination =
| radius_earth = {{val|1.64|0.19|0.14}}
}}
}}
{{OrbitboxPlanet
{{OrbitboxPlanet
| exoplanet = [[Kepler-9b|b]]
| exoplanet = [[Kepler-9b|b]]
| mass = 0.252 ± 0.013
| mass_earth = {{val|44.71|0.24}}
| semimajor = {{val|0.14276088|0.00000014}}
| radius =0.842 ± 0.069
| period = 19.24
| period = 19.247
| semimajor = 0.140 ± 0.001
| eccentricity = {{val|0.06378|0.00040}}
| inclination = {{val|88.936|0.030}}
| eccentricity = 0
| radius_earth = {{val|8.252|0.094}}
}}
}}
{{OrbitboxPlanet
{{OrbitboxPlanet
| exoplanet = [[Kepler-9c|c]]
| exoplanet = [[Kepler-9c|c]]
| mass = 0.171 ± 0.013
| mass_earth = {{val|30.79|0.17}}
| semimajor = {{val|0.22889876|0.00000053}}
| radius =0.823 ± 0.067
| period = 38.91
| period = 38.944
| semimajor = 0.225 ± 0.001
| eccentricity = {{val|0.067990|0.000068}}
| inclination = {{val|89.180|0.015}}
| eccentricity = 0
| radius_earth = {{val|8.077|0.092}}
}}
}}
{{Orbitbox end}}
{{Orbitbox end}}


== See also ==
==See also==
* [[List of extrasolar planets]]
* [[List of extrasolar planets]]
* [[Kepler Mission]]
* [[Kepler Mission]]


== References ==
==References==
{{reflist}}
{{reflist|refs=

* Keith Cooper (26 August 2010). [http://astronomynow.com/news/n1008/26kepler/ "Kepler finds first double planet transiting system"], ''[[Astronomy Now]]''. Accessed 7 September 2010.
<ref name="Borsato2019">{{cite journal | title=HARPS-N radial velocities confirm the low densities of the Kepler-9 planets | last1=Borsato | first1=L. | last2=Malavolta | first2=L. | last3=Piotto | first3=G. | last4=Buchhave | first4=L. A. | last5=Mortier | first5=A. | last6=Rice | first6=K. | last7=Cameron | first7=A. C. | last8=Coffinet | first8=A. | last9=Sozzetti | first9=A. | last10=Charbonneau | first10=D. | last11=Cosentino | first11=R. | last12=Dumusque | first12=X. | last13=Figueira | first13=P.| last14=Latham | first14=D. W. | last15=Lopez-Morales | first15=M. | last16=Mayor | first16=M. | last17=Micela | first17=G. | last18=Molinari | first18=E. | last19=Pepe | first19=F. | last20=Phillips | first20=D. | last21=Poretti | first21=E. | last22=Udry | first22=S. | last23=Watson | first23=C. | display-authors=1 | journal=Monthly Notices of the Royal Astronomical Society | volume=484 | issue=3 | year=2019 | pages=3233–3243 | arxiv=1901.05471 | bibcode=2019MNRAS.484.3233B | doi=10.1093/mnras/stz181 | doi-access=free | s2cid=85454312 }}</ref>

<ref name="EPE">{{cite encyclopedia | title=Planet Kepler-9 b | url=https://exoplanet.eu/catalog/kepler_9_b--741/ | encyclopedia=[[Extrasolar Planets Encyclopaedia]] | access-date=19 December 2017 }}</ref>

<ref name="Freudenthal2018">{{cite journal | title=Kepler Object of Interest Network. II. Photodynamical modelling of Kepler-9 over 8 years of transit observations | url=https://www.aanda.org/articles/aa/full_html/2018/10/aa33436-18/aa33436-18.html | last1=Freudenthal | first1=J. | last2=von Essen | first2=C. | last3=Dreizler | first3=S. | last4=Wedemeyer | first4=S. | last5=Agol | first5=E. | last6=Morris | first6=B. M. | last7=Becker | first7=A. C. | last8=Mallonn | first8=M. | last9=Hoyer | first9=S. | last10=Ofir | first10=A. | last11=Tal-Or | first11=L. | last12=Deeg | first12=H. J. | last13=Herrero | first13=E. | last14=Ribas | first14=I. | last15=Khalafinejad | first15=S. | last16=Hernández | first16=J. | last17=Rodríguez S. | first17=M. M. | display-authors=1 | journal=Astronomy and Astrophysics | volume=618 | at=A41 | year=2018 | arxiv=1807.00007 | bibcode=2018A&A...618A..41F | bibcode-access=free | doi=10.1051/0004-6361/201833436 | doi-access=free }}</ref>

<ref name="Gaia DR3">{{Cite Gaia DR3|2099925719951103872}}</ref>

<ref name="Holman2010">{{Cite journal | title=Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations | url=http://www.astro.ubc.ca/people/gladman/a520/Holmanetal2010.pdf | last1=Holman | first1=M. J. | last2=Fabrycky | first2=D. C. | last3=Ragozzine | first3=D. | last4=Ford | first4=E. B. | last5=Steffen | first5=J. H. | last6=Welsh | first6=W. F. | last7=Lissauer | first7=J. J. | last8=Latham | first8=D. W. | last9=Marcy | first9=G. W. | last10=Walkowicz | first10=L. M. | last11=Batalha | first11=N. M. | last12=Jenkins | first12=J. M. | last13=Rowe | first13=J. F. | last14=Cochran | first14=W. D. | last15=Fressin | first15=F. | last16=Torres | first16=G. | last17=Buchhave | first17=L. A. | last18=Sasselov | first18=D. D. | last19=Borucki | first19=W. J. | last20=Koch | first20=D. G. | last21=Basri | first21=G. | last22=Brown | first22=T. M. | last23=Caldwell | first23=D. A. | last24=Charbonneau | first24=D. | last25=Dunham | first25=E. W. | last26=Gautier | first26=T. N. | last27=Geary | first27=J. C. | last28=Gilliland | first28=R. L. | last29=Haas | first29=M. R. | last30=Howell | first30=S. B. | display-authors=1 | journal=Science | volume=330 | issue=6000 | pages=51–54 | year=2010 | bibcode=2010Sci...330...51H | doi=10.1126/science.1195778 | pmid=20798283 | s2cid=8141085 }}</ref>

<ref name="JPL2714">{{cite press release | author=<!--Staff writer(s); no by-line.--> | title=NASA's Kepler Mission Discovers Two Planets Transiting Same Star | url=https://www.jpl.nasa.gov/news/news.php?feature=2714 | location=Pasadena, California | publisher=[[Jet Propulsion Laboratory]] | date=2010-08-26 | access-date=2019-11-28}}</ref>

<ref name="McQuillan2013">{{cite journal | title=Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators | last1=McQuillan | first1=A. | last2=Mazeh | first2=T. | last3=Aigrain | first3=S. | journal=The Astrophysical Journal Letters | volume=775 | issue=1 | at=L11 | year=2013 | arxiv=1308.1845 | bibcode=2013ApJ...775L..11M | bibcode-access=free | doi=10.1088/2041-8205/775/1/L11 | doi-access=free }}</ref>

<ref name="Mission overview">{{cite web | title=Mission overview | url=https://www.nasa.gov/mission_pages/kepler/overview/index.html | work=Kepler and K2 | date=13 April 2015 | publisher=NASA | access-date=2 December 2017}}</ref>

<ref name="Roman1987">{{cite journal | title=Identification of a Constellation From a Position | last1=Roman | first1=Nancy G. | journal=Publications of the Astronomical Society of the Pacific | volume=99 | issue=617 | pages=695–699 | date=1987 | bibcode=1987PASP...99..695R | doi=10.1086/132034 | doi-access=free }} [http://vizier.u-strasbg.fr/vizier/VizieR/constellations.htx Vizier query form ]</ref>

<ref name="Simbad">{{cite simbad | title=Kepler-9 | access-date=2019-11-29 }}</ref>

<ref name="Torres2011">{{cite journal | title=Modeling Kepler Transit Light Curves as False Positives: Rejection of Blend Scenarios for Kepler-9, and Validation of Kepler-9 d, A Super-earth-size Planet in a Multiple System | last1=Torres | first1=Guillermo | last2=Fressin | first2=François | last3=Batalha | first3=Natalie M. | last4=Borucki | first4=William J. | last5=Brown | first5=Timothy M. | last6=Bryson | first6=Stephen T. | last7=Buchhave | first7=Lars A. | last8=Charbonneau | first8=David | last9=Ciardi | first9=David R. | last10=Dunham | first10=Edward W. | last11=Fabrycky | first11=Daniel C. | last12=Ford | first12=Eric B. | last13=Gautier Iii | first13=Thomas N. | last14=Gilliland | first14=Ronald L. | last15=Holman | first15=Matthew J. | last16=Howell | first16=Steve B. | last17=Isaacson | first17=Howard | last18=Jenkins | first18=Jon M. | last19=Koch | first19=David G. | last20=Latham | first20=David W | last21=Lissauer | first21=Jack J | last22=Marcy | first22=Geoffrey W | last23=Monet | first23=David G | last24=Prsa | first24=Andrej | last25=Quinn | first25=Samuel N. | last26=Ragozzine | first26=Darin | last27=Rowe | first27=Jason F. | last28=Sasselov | first28=Dimitar D. | last29=Steffen | first29=Jason H. | last30=Welsh | first30=William F. | display-authors=1 | journal=The Astrophysical Journal | volume=727 | issue=1 | at=24 | year=2011 | arxiv=1008.4393 | bibcode=2011ApJ...727...24T | bibcode-access=free | doi=10.1088/0004-637X/727/1/24 | doi-access=free }}</ref>

<ref name="Wang2018">{{Cite journal | title=Stellar Spin–Orbit Alignment for Kepler-9, a Multi-transiting Planetary System with Two Outer Planets Near 2:1 Resonance | last1=Wang | first1=Songhu | last2=Addison | first2=Brett | last3=Fischer | first3=Debra A. | last4=Brewer | first4=John M. | last5=Isaacson | first5=Howard | last6=Howard | first6=Andrew W. | last7=Laughlin | first7=Gregory | display-authors=1 | journal=The Astronomical Journal | volume=155 | issue=2 | at=70 | year=2018 | arxiv=1712.06409 | bibcode=2018AJ....155...70W | bibcode-access=free | doi=10.3847/1538-3881/aaa2fb | doi-access=free }}</ref>

}}

==External links==
* Keith Cooper (26 August 2010). [https://web.archive.org/web/20100831011606/http://www.astronomynow.com/news/n1008/26kepler/ "Kepler finds first double planet transiting system"], ''[[Astronomy Now]]''. Accessed 7 September 2010.


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{{Sky|19|2|17.76|+|38|24|3.2|1330}}
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[[Category:Planetary systems with three confirmed planets]]
[[Category:Planetary systems with three confirmed planets]]
[[Category:Lyra (constellation)]]
[[Category:Lyra]]
[[Category:Kepler Objects of Interest|9]]
[[Category:Kepler objects of interest|9]]
[[Category:Planetary transit variables]]
[[Category:Planetary transit variables]]
[[Category:G-type main-sequence stars]]

Latest revision as of 04:22, 18 July 2024

Kepler-9

An artist's impression of Kepler-9, including planets Kepler-9b and c
Observation data
Epoch J2000      Equinox J2000
Constellation Lyra[1]
Right ascension 19h 2m 17.7544s[2]
Declination +38° 24′ 03.177″[2]
Apparent magnitude (V) 13.9[3]
Astrometry
Proper motion (μ) RA: 2.472(13) mas/yr[2]
Dec.: −14.691(15) mas/yr[2]
Parallax (π)1.5823 ± 0.0120 mas[2]
Distance2,060 ± 20 ly
(632 ± 5 pc)
Characteristics
Spectral type G2V
Details[4]
Mass1.022+0.029
−0.039 M☉
Radius0.958±0.020 R☉
Surface gravity (log g)4.49+0.02
−0.03 cgs
Temperature5774±60 K
Metallicity [Fe/H]+0.05±0.07 dex
Rotation16.746±0.077 days[5]
Rotational velocity (v sin i)2.74±0.40[6] km/s
Age2.0+2.0
−1.3 Gyr
Other designations
KOI-377, KIC 3323887, 2MASS J19021775+3824032[7]
Database references
SIMBADdata
KICdata

Kepler-9 is a sunlike star in the constellation Lyra. Its planetary system, discovered by the Kepler Mission in 2010 was the first detected with the transit method found to contain multiple planets.

Nomenclature and history

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Kepler-9 was named for the Kepler Mission, a project headed by NASA that was designed to search for Earth-like planets.[8]

In June 2010, some 43 days after Kepler came online, its operating scientists submitted a list of over 700 exoplanet candidates for review. Of those, five were originally suspected to have more than one planet. Kepler-9 was one of the multiplanetary systems; it was identified as such when scientists noticed significant variations in the time intervals at which Kepler-9 was transited.[9] Kepler-9 holds the first multiplanetary system discovered using the transit method. It is also the first planetary system where transiting planets were confirmed through transit timing variations method, allowing to calculate the masses of planets.[10] The discovery of the planets was announced on August 26, 2010.[9]

Characteristics

[edit]

Kepler-9 is located in the constellation Lyra that lies some 632 parsecs away from Earth. With a mass of 1.07 M☉ and a radius of 1.02 R☉, Kepler-9 is almost exactly the same size and width of the Sun, being only 7% more massive and 2% wider. Kepler-9 has an effective temperature of 5777 (± 61) K, as compared to the Sun's at 5778 K,[11] and is approximately 32% more metal-rich (in terms of iron) than the Sun. Kepler-9 is younger than the Sun, and is estimated to be one billion years old.[12]

Planetary system

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Light curves of the transiting planets of Kepler-9.

There are three confirmed planets, all in direct orbit. The outer two planets, Kepler-9b (the inner one) and Kepler-9c (the outer one), are low-density gas giants that are respectively 25% and 17% the mass of Jupiter and around 80% the radius of Jupiter. Both planets have a density less than that of water, similar to Saturn. The innermost planet, Kepler-9d, is a super-Earth with a radius that is 1.64 times that of Earth,[13][12] orbiting the star every 1.6 days. It is estimated that there is a 0.59% chance that the discoveries are false.[12]

From Kepler-9d (closest to star) to Kepler-9b (second from star), the ratio of their orbits is 1:12. However, the ratio of the orbits of the two outer planets is 1:2, a relationship known as a mean motion resonance. Kepler-9b and Kepler-9c are the first transiting planets detected in such an orbital configuration.[14] The resonance causes the orbital speeds of each planet to change, and thus causes the transit times of the two planets to oscillate. The period of Kepler-9b is increasing by 4 minutes per orbit, while that of Kepler-9c is decreasing by 39 minutes per orbit. These orbital changes allowed the masses of the planets (a parameter not normally obtainable via the transit method) to be estimated using a dynamical model. The mass estimates were further refined using radial velocity measurements obtained with the HIRES instrument of the Keck 1 telescope.[14][15]

Kepler-9b and 9c are thought to have formed beyond the "frost line". They are then thought to have migrated inward due to interactions with the remains of the protoplanetary disk. They would have been captured into orbital resonance during this migration.[14]

In 2021, it was found the orbital plane of Kepler-9b and Kepler-9c are slowly changing, likely under the gravitational influence of the additional giant planet.[16]

The Kepler-9 planetary system[13][12]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
d — 0.02730+0.00042
−0.00043 		1.592851±0.000045 0 — 1.64+0.19
−0.14 R🜨
b 44.71±0.24 M🜨 0.14276088±0.00000014 19.247 0.06378±0.00040 88.936±0.030° 8.252±0.094 R🜨
c 30.79±0.17 M🜨 0.22889876±0.00000053 38.944 0.067990±0.000068 89.180±0.015° 8.077±0.092 R🜨

See also

[edit]

References

[edit]
  1. ^ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
  2. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ "Planet Kepler-9 b". Extrasolar Planets Encyclopaedia. Retrieved 19 December 2017.
  4. ^ Borsato, L.; et al. (2019). "HARPS-N radial velocities confirm the low densities of the Kepler-9 planets". Monthly Notices of the Royal Astronomical Society. 484 (3): 3233–3243. arXiv:1901.05471. Bibcode:2019MNRAS.484.3233B. doi:10.1093/mnras/stz181. S2CID 85454312.
  5. ^ McQuillan, A.; Mazeh, T.; Aigrain, S. (2013). "Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators". The Astrophysical Journal Letters. 775 (1). L11. arXiv:1308.1845. Bibcode:2013ApJ...775L..11M. doi:10.1088/2041-8205/775/1/L11.
  6. ^ Wang, Songhu; et al. (2018). "Stellar Spin–Orbit Alignment for Kepler-9, a Multi-transiting Planetary System with Two Outer Planets Near 2:1 Resonance". The Astronomical Journal. 155 (2). 70. arXiv:1712.06409. Bibcode:2018AJ....155...70W. doi:10.3847/1538-3881/aaa2fb.
  7. ^ "Kepler-9". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-29.
  8. ^ "Mission overview". Kepler and K2. NASA. 13 April 2015. Retrieved 2 December 2017.
  9. ^ a b "NASA's Kepler Mission Discovers Two Planets Transiting Same Star" (Press release). Pasadena, California: Jet Propulsion Laboratory. 2010-08-26. Retrieved 2019-11-28.
  10. ^ Nancy Atkinson (26 August 2010). "Kepler Discovers Multi-Planet System". Universe Today. Retrieved 13 January 2011.
  11. ^ David Williams (1 September 2004). "Sun Fact Sheet". Goddard Space Flight Center. NASA. Retrieved 20 March 2011.
  12. ^ a b c d Torres, Guillermo; et al. (2011). "Modeling Kepler Transit Light Curves as False Positives: Rejection of Blend Scenarios for Kepler-9, and Validation of Kepler-9 d, A Super-earth-size Planet in a Multiple System". The Astrophysical Journal. 727 (1). 24. arXiv:1008.4393. Bibcode:2011ApJ...727...24T. doi:10.1088/0004-637X/727/1/24.
  13. ^ a b Freudenthal, J.; et al. (2018). "Kepler Object of Interest Network. II. Photodynamical modelling of Kepler-9 over 8 years of transit observations". Astronomy and Astrophysics. 618. A41. arXiv:1807.00007. Bibcode:2018A&A...618A..41F. doi:10.1051/0004-6361/201833436.
  14. ^ a b c Holman, M. J.; et al. (2010). "Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations" (PDF). Science. 330 (6000): 51–54. Bibcode:2010Sci...330...51H. doi:10.1126/science.1195778. PMID 20798283. S2CID 8141085.
  15. ^ Alexander, Amir (2010-08-27). "From the Ground and from Space, New Planetary Systems Unveiled". Planetary Society web site. The Planetary Society. Archived from the original on 2010-09-01. Retrieved 2010-08-27.
  16. ^ Shahaf, Sahar; Mazeh, Tsevi; Zucker, Shay; Fabrycky, Daniel (2021), "Systematic search for long-term transit duration changes in Kepler transiting planets", Monthly Notices of the Royal Astronomical Society, 505: 1293–1310, arXiv:2105.04318, Bibcode:2021MNRAS.505.1293S, doi:10.1093/mnras/stab1359
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