K2-32
{{Short description|Yellowish-hued star in the constellation Ophiuchus}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000
| constell = Ophiuchus
| appmag_v = {{val|12.31|0.02}}
}}
{{Starbox character
| appmag_1_passband = J
| appmag_1 = {{val|10.404|0.024}}
| appmag_2_passband = H
| appmag_2 = {{val|9.993|0.025}}
| appmag_3_passband = K
| appmag_3 = {{val|9.821|0.019}}
| variable = Planetary transit variable
}}
{{Starbox astrometry
| radial_v = {{val|−1.82|0.14}}
| prop_mo_ra = {{val|−16.662|(18)}}
| prop_mo_dec = {{val|−53.564|(13)}}
| parallax = 6.3939
| p_error = 0.0153
| absmag_v =
}}
{{Starbox detail
| 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 }}
}}
{{Starbox reference
| Simbad = K2-32
}}
{{Starbox end}}
K2-32 is a G9-type main sequence star slightly smaller and less massive than the sun. Four confirmed transiting exoplanets are known to orbit this star. 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.
Planetary system
=Discovery=
The star K2-32 was initially found to have three transiting planet candidates by Andrew Vanderburg and collaborators in 2016. The innermost planet candidate, at that time, K2-32b was confirmed using radial velocity measurements made with the Keck telescope. Confirmation of planets c and d was made by Sinukoff et al. using adaptive optics imaging and computer analysis to eliminate possible false positives.
The Earth-sized planet K2-32e was discovered and validated by René Heller and team in 2019.
=Characteristics=
With periods of 4.34, 8.99, 20.66 and 31.71 days the four planets orbits 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. All four planets are well inside even the optimistic inner boundary of the habitable zone located at 0.58 astronomical units.
File:K2-32 planetary system.png
{{OrbitboxPlanet begin
}}
{{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
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