View source for K2-32

{{Short description|Yellowish-hued star in the constellation Ophiuchus}}
{{Starbox begin
| name = K2-32
}}
{{Starbox observe
| epoch = J2000
| constell = [[Ophiuchus]]<ref name="Roman1987"/>
| ra = {{RA|16|49|42.2602}}<ref name="Gaia EDR3"/>
| dec = {{DEC|−19|32|34.151}}<ref name="Gaia EDR3"/>
| appmag_v = {{val|12.31|0.02}}<ref name="Petigura2017"/>
}}
{{Starbox character
| class = G9V<ref name="Dai2016"/>
| appmag_1_passband = J
| appmag_1 = {{val|10.404|0.024}}<ref name="Skrutskie2006"/>
| appmag_2_passband = H
| appmag_2 = {{val|9.993|0.025}}<ref name="Skrutskie2006"/>
| appmag_3_passband = K
| appmag_3 = {{val|9.821|0.019}}<ref name="Skrutskie2006"/>
| variable = [[Variable star#Planetary transits|Planetary transit variable]]<ref name="Sinukoff2016"/>
}}
{{Starbox astrometry
| radial_v = {{val|−1.82|0.14}}<ref name="Vanderburg2016"/>
| prop_mo_ra = {{val|−16.662|(18)}}<ref name="Gaia EDR3"/>
| prop_mo_dec = {{val|−53.564|(13)}}<ref name="Gaia EDR3"/>
| parallax = 6.3939
| p_error = 0.0153
| parallax_footnote = <ref name="Gaia EDR3"/>
| absmag_v =
}}
{{Starbox detail
| source = <ref name="Petigura2017"/>
| mass = {{val|0.856|0.028}}
| radius = {{val|0.845|0.044|0.035}}
| luminosity =
| gravity = {{val|4.49|0.05}}
| temperature = {{val|5275|60}}
| metal_fe = {{val|−0.02|0.04}}
| rotation =
| rotational_velocity = 0.7
| age_gyr = {{val|7.9|4.5}}
}}
{{Starbox catalog
| names = {{odlist | 2MASS=J16494226-1932340 | Gaia DR2=4130539180358512768 | EPIC=205071984 }}<ref name="Simbad"/>
}}
{{Starbox reference
| Simbad = K2-32
}}
{{Starbox end}}
'''K2-32''' is a [[G-type main-sequence star|G9-type]] [[main sequence]] star slightly smaller and less massive than the sun.<ref name="Dai2016"/> Four confirmed [[Transit (astronomy)|transiting]] [[exoplanet]]s are known to orbit this star.<ref name="Heller2019"/> A study of [[atmospheric escape]] from the planet K2-32b caused by high-energy stellar irradiation indicates that the star has always been a very slow rotator.<ref name="Kubyshkina2019"/>
==Planetary system==
===Discovery===
The star K2-32 was initially found to have three transiting planet candidates by Andrew Vanderburg and collaborators in 2016.<ref name="Vanderburg2016"/> The innermost planet candidate, at that time, K2-32b was confirmed using [[radial velocity]] measurements made with the [[W. M. Keck Observatory|Keck telescope]].<ref name="Dai2016"/> Confirmation of planets c and d was made by Sinukoff ''et al.'' using [[adaptive optics]] imaging and computer analysis to eliminate possible [[false positive]]s.<ref name="Sinukoff2016"/>
The Earth-sized planet K2-32e was discovered and validated by René Heller and team in 2019.<ref name="Heller2019"/><ref name="sci-news"/>
[[File:K2-32 transit light curves.png|thumb|center|alt=|Transit light curves of all four planets orbiting the star K2-32.<ref name="Heller2019"/>]]
===Characteristics===
With periods of 4.34, 8.99, 20.66 and 31.71 days the four planets [[orbit]]s are very close to a 1:2:5:7 [[orbital resonance]] chain. The densities of planets b, c, and d are between those of [[Saturn]] and [[Neptune]], which suggests large and massive atmospheres. The planet K2-32e with a radius almost identical to that of the Earth is almost certainly a [[terrestrial planet]].<ref name="Heller2019"/> All four planets are well inside even the optimistic inner boundary of the [[Circumstellar habitable zone|habitable zone]] located at 0.58 [[astronomical unit]]s.<ref name="Wittenmyer2018"/>
[[File:K2-32 planetary system.png|thumb|center|alt=|Planetary system of the star K2-32 showing planetary radii and orbital resonances.<ref name="Heller2019"/>]]
{{OrbitboxPlanet begin
| table_ref = <ref name="Heller2019"/><ref name="Petigura2017"/><ref name="Lillo-Box2020"/>
}}
{{OrbitboxPlanet
| exoplanet = e
| mass_earth = 2.1{{±|1.3|1.1}}
| semimajor = 0.04899{{±|0.00041|0.00038}}
| period = 4.34934{{±|0.00039}}
| eccentricity = 0.043{{±|0.048|0.030}}
| inclination = 89.0{{±|0.7}}
| radius_earth = 1.212{{±|0.052|0.046}}
}}
{{OrbitboxPlanet
| exoplanet = b
| mass_earth = 15.0{{±|1.8|1.7}}
| semimajor = 0.07950{{±|0.00066|0.00062}}
| period = 8.992{{±|0.00008}}
| eccentricity = 0.03{{±|0.032|0.02}}
| inclination = 89.0{{±|0.5|0.3}}
| radius_earth = 5.299{{±|0.191}}
}}
{{OrbitboxPlanet
| exoplanet = c
| mass_earth = 8.1{{±|2.4}}
| semimajor = 0.13843{{±|0.00115|0.00108}}
| period = 20.66093{{±|0.00080|0.00079}}
| eccentricity = 0.049{{±|0.046|0.035}}
| inclination = 89.4{{±|0.3|0.2}}
| radius_earth = 2.134{{±|0.123|0.102}}
}}
{{OrbitboxPlanet
| exoplanet = d
| mass_earth = 6.7{{±|2.5}}
| semimajor = 0.18422{{±|0.00152|0.00144}}
| period = 31.71701{{±|0.00101|0.00096}}
| eccentricity = 0.05{{±|0.053|0.035}}
| inclination = 89.4{{±|0.1}}
| radius_earth = 3.484{{±|0.112|0.129}}
}}
{{Orbitbox end}}
==References==
{{reflist|refs=
<ref name="Dai2016">{{cite journal | title=Doppler Monitoring of Five K2 Transiting Planetary Systems | last1=Dai | first1=Fei | last2=Winn | first2=Joshua N. | last3=Albrecht | first3=Simon | last4=Arriagada | first4=Pamela | last5=Bieryla | first5=Allyson | last6=Butler | first6=R. Paul | last7=Crane | first7=Jeffrey D. | last8=Hirano | first8=Teriyaki | last9=Johnson | first9=John Asher | last10=Kiilerich | first10=Amanda | last11=Latham | first11=David W. | last12=Narita | first12=Norio | last13=Nowak | first13=Grzegorz | last14=Palle | first14=Enric | last15=Ribas | first15=Ignasi | last16=Rogers | first16=Leslie A. | last17=Sanchis-Ojeda | first17=Roberto | last18=Shectman | first18=Stephen A. | last19=Teske | first19=Johanna K. | last20=Thompson | first20=Ian B. | last21=Eylen | first21=Vincent Van | last22=Vanderburg | first22=Andrew | last23=Wittenmyer | first23=Robert A. | last24=Yu | first24=Liang | display-authors=1 | journal=The Astrophysical Journal | volume=823 | issue=2 | article-number=115 | year=2016 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=1604.01413 | bibcode=2016ApJ...823..115D | bibcode-access=free | doi=10.3847/0004-637X/823/2/115 | doi-access=free }}</ref>
<ref name="Gaia EDR3">{{Cite Gaia EDR3|4130539180358512768}}</ref>
<ref name="Heller2019">{{cite journal | title=Transit least-squares survey. I. Discovery and validation of an Earth-sized planet in the four-planet system K2-32 near the 1:2:5:7 resonance | url=https://www.aanda.org/articles/aa/full_html/2019/05/aa35276-19/aa35276-19.html | last1=Heller | first1=René | last2=Rodenbeck | first2=Kai | last3=Hippke | first3=Michael | journal=Astronomy and Astrophysics | volume=625 | article-number=A31 | year=2019 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=1904.00651 | bibcode=2019A&A...625A..31H | bibcode-access=free | doi=10.1051/0004-6361/201935276 | doi-access=free }}</ref>
<ref name="Kubyshkina2019">{{cite journal | title=Close-in Sub-Neptunes Reveal the Past Rotation History of Their Host Stars: Atmospheric Evolution of Planets in the HD 3167 and K2-32 Planetary Systems | last1=Kubyshkina | first1=D. | last2=Cubillos | first2=P. E. | last3=Fossati | first3=L. | last4=Erkaev | first4=N. V. | last5=Johnstone | first5=C. P. | last6=Kislyakova | first6=K. G. | last7=Lammer | first7=H. | last8=Lendl | first8=M. | last9=Odert | first9=P. | last10=Güdel | first10=M. | display-authors=1 | journal=The Astrophysical Journal | volume=879 | issue=1 | article-number=26 | year=2019 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=1906.12153 | bibcode=2019ApJ...879...26K | bibcode-access=free | doi=10.3847/1538-4357/ab1e42 | doi-access=free }}</ref>
<ref name="Lillo-Box2020">{{cite journal | title=Masses for the seven planets in K2-32 and K2-233 | last1=Lillo-Box | first1=J. | last2=Lopez | first2=T. A. | last3=Santerne | first3=A. | last4=Nielsen | first4=L. D. | last5=Barros | first5=S. C. C. | last6=Deleuil | first6=M. | last7=Acuña | first7=L. | last8=Mousis | first8=O. | last9=Sousa | first9=S. G. | last10=Adibekyan | first10=V. | last11=Armstrong | first11=D. J. | last12=Barrado | first12=D. | last13=Bayliss | first13=D. | last14=Brown | first14=D. J. A. | last15=Demangeon | first15=O. D. S. | last16=Dumusque | first16=X. | last17=Figueira | first17=P. | last18=Hojjatpanah | first18=S. | last19=Osborn | first19=H. P. | last20=Santos | first20=N. C. | last21=Udry | first21=S. | display-authors=1 | journal=Astronomy & Astrophysics | volume=640 | article-number=A48 | year=2020 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=2006.01102 | bibcode=2020A&A...640A..48L | bibcode-access=free | doi=10.1051/0004-6361/202037896 | doi-access=free }}</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 | year=1987 | bibcode=1987PASP...99..695R | bibcode-access=free | doi=10.1086/132034 | doi-access=free }} [http://vizier.u-strasbg.fr/vizier/VizieR/constellations.htx Vizier query form ]</ref>
<ref name="Petigura2017">{{cite journal | title=Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes | last1=Petigura | first1=Erik A. | last2=Sinukoff | first2=Evan | last3=Lopez | first3=Eric D. | last4=Crossfield | first4=Ian J. M. | last5=Howard | first5=Andrew W. | last6=Brewer | first6=John M. | last7=Fulton | first7=Benjamin J. | last8=Isaacson | first8=Howard T. | last9=Ciardi | first9=David R. | last10=Howell | first10=Steve B. | last11=Everett | first11=Mark E. | last12=Horch | first12=Elliott P. | last13=Hirsch | first13=Lea A. | last14=Weiss | first14=Lauren M. | last15=Schlieder | first15=Joshua E. | display-authors=1 | journal=The Astronomical Journal | volume=153 | issue=4 | article-number=142 | year=2017 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=1702.00013 | bibcode=2017AJ....153..142P | bibcode-access=free | doi=10.3847/1538-3881/aa5ea5| doi-access=free }}</ref>
<ref name="sci-news">{{cite press release | author=<!--Staff writer(s); no by-line.--> | title=Astronomers Discover 18 New Small Exoplanets in Kepler Data | url=http://www.sci-news.com/astronomy/transit-least-squares-exoplanets-kepler-data-07229.html | publisher=Sci-News.com | date=2019-05-28 | access-date=2019-09-27}}</ref>
<ref name="Simbad">{{cite simbad | title=K2-32 | access-date=2019-09-01 }}</ref>
<ref name="Sinukoff2016">{{cite journal | title=Eleven Multiplanet Systems From K2 Campaigns 1 and 2 and the Masses of Two Hot Super-Earths | last1=Sinukoff | first1=Evan | last2=Howard | first2=Andrew W. | last3=Petigura | first3=Erik A. | last4=Schlieder | first4=Joshua E. | last5=Crossfield | first5=Ian J. M. | last6=Ciardi | first6=David R. | last7=Fulton | first7=Benjamin J. | last8=Isaacson | first8=Howard | last9=Aller | first9=Kimberly M. | last10=Baranec | first10=Christoph | last11=Beichman | first11=Charles A. | last12=Hansen | first12=Brad M. S. | last13=Knutson | first13=Heather A. | last14=Law | first14=Nicholas M. | last15=Liu | first15=Michael C. | last16=Riddle | first16=Reed | last17=Dressing | first17=Courtney D. | display-authors=1 | journal=The Astrophysical Journal | volume=827 | issue=1 | article-number=78 | year=2016 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=1511.09213 | bibcode=2016ApJ...827...78S | bibcode-access=free | doi=10.3847/0004-637X/827/1/78 | doi-access=free }}</ref>
<ref name="Skrutskie2006">{{cite journal | title=The Two Micron All Sky Survey (2MASS) | last1=Skrutskie | first1=Michael F. | last2=Cutri | first2=Roc M. | last3=Stiening | first3=Rae | last4=Weinberg | first4=Martin D. | last5=Schneider | first5=Stephen E. | last6=Carpenter | first6=John M. | last7=Beichman | first7=Charles A. | last8=Capps | first8=Richard W. | last9=Chester | first9=Thomas | last10=Elias | first10=Jonathan H. | last11=Huchra | first11=John P. | last12=Liebert | first12=James W. | last13=Lonsdale | first13=Carol J. | last14=Monet | first14=David G. | last15=Price | first15=Stephan | last16=Seitzer | first16=Patrick | last17=Jarrett | first17=Thomas H. | last18=Kirkpatrick | first18=J. Davy | last19=Gizis | first19=John E. | last20=Howard | first20=Elizabeth V. | last21=Evans | first21=Tracey E. | last22=Fowler | first22=John W. | last23=Fullmer | first23=Linda | last24=Hurt | first24=Robert L. | last25=Light | first25=Robert M. | last26=Kopan | first26=Eugene L. | last27=Marsh | first27=Kenneth A. | last28=McCallon | first28=Howard L. | last29=Tam | first29=Robert | last30=Van Dyk | first30=Schuyler D. | last31=Wheelock | first31=Sherry L. | display-authors=1 | journal=The Astronomical Journal | date=1 February 2006 | volume=131 | issue=2 | pages=1163–1183 | bibcode=2006AJ....131.1163S | bibcode-access=free | doi=10.1086/498708 | doi-access=free }} [http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=II/246/out&2MASS===16494226-1932340 Vizier catalog entry ]</ref>
<ref name="Vanderburg2016">{{cite journal | title=Planetary Candidates from the First Year of the K2 Mission | last1=Vanderburg | first1=Andrew | last2=Latham | first2=David W. | last3=Buchhave | first3=Lars A. | last4=Bieryla | first4=Allyson | last5=Berlind | first5=Perry | last6=Calkins | first6=Michael L. | last7=Esquerdo | first7=Gilbert A. | last8=Welsh | first8=Sophie | last9=Johnson | first9=John Asher | display-authors=1 | journal=The Astrophysical Journal Supplement Series | volume=222 | issue=1 | article-number=14 | year=2016 | page=<!-- to prevent citation bot adding nonexistent page number--> | arxiv=1511.07820 | bibcode=2016ApJS..222...14V | bibcode-access=free | doi=10.3847/0067-0049/222/1/14 | doi-access=free }}</ref>
<ref name="Wittenmyer2018">{{cite journal | title=The K2-HERMES Survey. I. Planet-candidate Properties from K2 Campaigns 1–3 | last1=Wittenmyer | first1=Robert A. | last2=Sharma | first2=Sanjib | last3=Stello | first3=Dennis | last4=Buder | first4=Sven | last5=Kos | first5=Janez | last6=Asplund | first6=Martin | last7=Duong | first7=Ly | last8=Lin | first8=Jane | last9=Lind | first9=Karin | last10=Ness | first10=Melissa | last11=Zwitter | first11=Tomaz | last12=Horner | first12=Jonathan | last13=Clark | first13=Jake | last14=Kane | first14=Stephen R. | last15=Huber | first15=Daniel | last16=Bland-Hawthorn | first16=Joss | last17=Casey | first17=Andrew R. | last18=De Silva | first18=Gayandhi M. | last19=D'Orazi | first19=Valentina | last20=Freeman | first20=Ken | last21=Martell | first21=Sarah | last22=Simpson | first22=Jeffrey D. | last23=Zucker | first23=Daniel B. | last24=Anguiano | first24=Borja | last25=Casagrande | first25=Luca | last26=Esdaile | first26=James | last27=Hon | first27=Marc | last28=Ireland | first28=Michael | last29=Kafle | first29=Prajwal R. | last30=Khanna | first30=Shourya | last31=Marshall | first31=J. P. | last32=Mohd Saddon | first32=Mohd Hafiz | last33=Traven | first33=Gregor | last34=Wright | first34=Duncan | display-authors=1 | journal=The Astronomical Journal | volume=155 | issue=2 | year=2018 | page=<!-- to prevent citation bot adding nonexistent page number--> | article-number=84 | arxiv=1712.06774 | bibcode=2018AJ....155...84W | bibcode-access=free | doi=10.3847/1538-3881/aaa3e4 | doi-access=free }}</ref>
}}
==External links==
* [https://exoplanet.eu/catalog/k2_32_b--4035/ The Extrasolar Planets Encyclopaedia  entry for K2-32b]
* [https://exoplanet.eu/catalog/k2_32_c--4036/ The Extrasolar Planets Encyclopaedia  entry for K2-32c]
* [https://exoplanet.eu/catalog/k2_32_d--4037/ The Extrasolar Planets Encyclopaedia  entry for K2-32d]
* [https://exoplanet.eu/catalog/k2_32_e--7070/ The Extrasolar Planets Encyclopaedia  entry for K2-32e]
{{Ophiuchus}}
{{DEFAULTSORT:K2-32}}
[[Category:G-type main-sequence stars]]
[[Category:Ophiuchus]]
[[Category:Planetary systems with four confirmed planets]]
[[Category:Planetary transit variables]]