Kepler-33#Planetary system
{{short description|Star in the constellation Cygnus}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000
| constell = Cygnus
| appmag_v = 13.988
}}
{{Starbox character
| class = G1IV
}}
{{Starbox astrometry
| radial_v = {{val|12.18|3.65}}
| prop_mo_ra = {{val|−1.107|(15)}}
| prop_mo_dec = {{val|−13.099|(14)}}
| parallax = 0.8136
| p_error = 0.0118
| absmag_v =
}}
{{Starbox detail
| mass = {{val|1.26|0.03|0.06}}
| radius = {{val|1.66|0.03}}
| temperature = {{val|5947|60}}
| metal_fe = {{val|0.14|0.04}}
| luminosity = {{val|3.1|0.2|0.1}}
| age_gyr = {{val|4.2|1.3|0.3}}
}}
{{Starbox catalog
| names = KOI-707, KIC 9458613, 2MASS J19161861+4600187, Gaia DR2 2127355923723254272
}}
{{Starbox reference
| Simbad = Kepler+33
}}
{{Starbox end}}
Kepler-33 is a star about {{convert|4000|ly|pc|lk=on|abbr=off}} in the constellation of Cygnus, with a system of five known planets. Having just begun to evolve off from the main sequence, its radius and mass are difficult to ascertain, although data available in 2020 shows its best-fit mass of 1.3{{Solar mass}} and radius of 1.6{{Solar radius}} are compatible with a model of a subgiant star.
Planetary system
The first detections of the candidate four-body planetary system were reported in February 2011.{{citation|arxiv=1102.0544|title=Transit Timing Observations from Kepler : I. Statistical Analysis of the First Four Months|year=2011|doi=10.1088/0067-0049/197/1/2|last1=Ford|first1=Eric B.|last2=Rowe|first2=Jason F.|last3=Fabrycky|first3=Daniel C.|last4=Carter|first4=Joshua A.|last5=Holman|first5=Matthew J.|last6=Lissauer|first6=Jack J.|last7=Ragozzine|first7=Darin|last8=Steffen|first8=Jason H.|last9=Batalha|first9=Natalie M.|last10=Borucki|first10=William J.|last11=Bryson|first11=Steve|last12=Caldwell|first12=Douglas A.|last13=Dunham|first13=Edward W.|last14=Gautier|first14=Thomas N.|last15=Jenkins|first15=Jon M.|last16=Koch|first16=David G.|last17=Li|first17=Jie|last18=Lucas|first18=Philip|last19=Marcy|first19=Geoffrey W.|last20=McCauliff|first20=Sean|last21=Mullally|first21=Fergal R.|last22=Quintana|first22=Elisa|last23=Still|first23=Martin|last24=Tenenbaum|first24=Peter|last25=Thompson|first25=Susan E.|last26=Twicken|first26=Joseph D.|journal=The Astrophysical Journal Supplement Series|volume=197|issue=1 |page=2|bibcode=2011ApJS..197....2F |s2cid=118472942}} On January 26, 2012, the planetary system around the star was confirmed, including a fifth planet. However, unlike some other planets confirmed via Kepler, their masses were initially not known, as Doppler spectroscopy measurements were not done before the announcement. Judging by their radii, b may be a large super-Earth or small hot Neptune while the other four are all likely to be the latter. {{As of|2022}}, the masses of planets e & f have been measured, with upper limits on the masses of planets c & d. These mass measurements confirm Kepler-33 d, e & f to be low-density, gaseous planets.
Planets b and c may actually be in a 7:3 resonance, as there is a 0.05 day discrepancy; there is also a small 0.18 day discrepancy between a 5:3 resonance between planets c and d. The other planets do not seem to be in any resonances, though near resonances are 3d:2e and 4e:3f.
The planetary system in its current configuration is highly susceptible to perturbations, therefore assuming stability, no additional giant planets can be located within 30 AU from the parent star.{{citation|arxiv=1702.07714|title=Effects of Unseen Additional Planetary Perturbers on Compact Extrasolar Planetary Systems|year=2017|doi=10.1093/mnras/stx461|last1=Becker|first1=Juliette C.|last2=Adams|first2=Fred C.|journal=Monthly Notices of the Royal Astronomical Society|volume=468|issue=1 |pages=549–563|doi-access=free |bibcode=2017MNRAS.468..549B |s2cid=119325005}}
{{OrbitboxPlanet begin
| name = Kepler-33
}}
{{OrbitboxPlanet
| exoplanet = b
| period = {{val|5.66816|0.00005}}
| semimajor = {{val|0.0673|0.0004|0.0012}}
| radius_earth = {{val|1.54|0.06|0.05}}
| eccentricity = <0.2
| inclination = >87.0
}}
{{OrbitboxPlanet
| exoplanet = c
| mass_earth = <19
| period = {{val|13.17552|0.00005}}
| semimajor = {{val|0.1181|0.0008|0.0020}}
| radius_earth = {{val|2.73|0.06}}
| eccentricity = <0.05
| inclination = >88.6
}}
{{OrbitboxPlanet
| exoplanet = d
| mass_earth = <8.2
| period = {{val|21.77574|0.00006|0.00004}}
| semimajor = {{val|0.165|0.001|0.003}}
| radius_earth = {{val|4.67|0.09}}
| eccentricity = <0.03
| inclination = >89.02
}}
{{OrbitboxPlanet
| exoplanet = e
| mass_earth = {{val|6.6|1.1|1.0}}
| period = {{val|31.7852|0.0002}}
| semimajor = {{val|0.212|0.001|0.004}}
| radius_earth = {{val|3.54|0.09|0.07}}
| eccentricity = <0.02
| inclination = {{val|89.4|0.1}}
}}
{{OrbitboxPlanet
| exoplanet = f
| mass_earth = {{val|8.2|1.6|1.2}}
| period = {{val|41.0274|0.0002}}
| semimajor = {{val|0.252|0.002|0.004}}
| radius_earth = {{val|3.96|0.09|0.07}}
| eccentricity = <0.02
| inclination = {{val|89.7|0.2|0.1}}
}}
{{Orbitbox end}}
See also
References
{{reflist|refs=
{{Cite Gaia DR3|2127355923723254272}}
{{cite encyclopedia |url=http://exoplanet.eu/star.php?st=Kepler-33 |title=Notes for star Kepler-33 |access-date=2012-02-01 |url-status=dead |archive-url=https://web.archive.org/web/20120426091050/http://exoplanet.eu/star.php?st=Kepler-33 |encyclopedia=Extrasolar Planets Encyclopaedia |archive-date=2012-04-26 }}
{{cite journal |last1=Sikora |first1=James |last2=Rowe |first2=Jason |display-authors=etal |date=December 2022 |title=Refining the Masses and Radii of the Star Kepler-33 and its Five Transiting Planets |journal=The Astronomical Journal |volume=164 |issue=6 |pages=242 |doi=10.3847/1538-3881/ac98c4 |arxiv=2211.00703 |bibcode=2022AJ....164..242S |doi-access=free }}
{{Cite constellation|Kepler-33}}
}}
{{Sky|19|16|18.61|+|46|00|18.8}}
{{Stars of Cygnus}}
Category:Cygnus (constellation)
Category:Planetary transit variables
Category:Planetary systems with five confirmed planets
{{Main-star-stub}}