Planet K2-18 b
| Name | K2-18 b | ||
| Planet Status | Confirmed | ||
| Discovered in | 2015 | ||
| Mass | 0.02807 ( -0.00503 +0.00535 ) MJ | ||
| Mass*sin(i) | — |  |
|
| Semi-Major Axis | 0.1429 ( -0.0065 +0.006 ) AU | ||
| Orbital Period | 32.939623 ( -0.0001 +9.5e-05 ) day | ||
| Eccentricity | 0.2 (± 0.08) | |
|
| ω | -5.7 ( -33.8 +46.4 ) deg | ||
| Tperi | — | ||
| Radius | 0.211 ( -0.02 +0.02 ) RJ | ||
| Inclination | 89.5785 ( -0.0088 +0.0079 ) deg | ||
| Update | 2021-02-05 | ||
| Detection Method | Primary Transit | ||
| Mass Detection Method | Theoretical | ||
| Radius Detection Method | Primary Transit | ||
| Primary transit | 2457264.39144 (± 0.00065) JD | ||
| Secondary transit | — | ||
| λ | — | ||
| Impact Parameter b | — | ||
| Time Vr=0 | — | ||
| Velocity Semiamplitude K | 3.55 ( -0.58 +0.57 ) m/s | ||
| Calculated temperature | 284.0 ( -15.0 +15.0 ) K | ||
| Measured temperature | — | ||
| Hottest point longitude | — | ||
| Geometric albedo | — | ||
| Surface gravity log(g/gH) | — | ||
| Alternate Names | EPIC 201912552 b, 2MASS J11301450+0735180 b, EPIC 201912552.01, WISE J113014.45+073516.8 b |
Star
K2-18| Name | K2-18 | ||
| Distance | 38.07 ( -0.08 +0.08 ) pc | ||
| Spectral type | M2.5 V | ||
| Apparent magnitude V | 13.5 | ||
| Mass | 0.36 ( -0.05 +0.05 ) MSun | ||
| Age | — | ||
| Effective temperature | 3457.0 ( -39.0 +39.0 ) K | ||
| Radius | 0.41 ( -0.04 +0.04 ) RSun | ||
| Metallicity [Fe/H] | 0.12 ( -0.16 +0.16 ) | ||
| Detected Disc | — | ||
| Magnetic Field | — | ||
| RA2000 | 11:30:14.5 | ||
| Dec2000 | +07:35:18 | ||
| Alternate Names | EPIC 201912552, 2MASS J11301450+0735180, WISE J113014.45+073516.8 | ||
| Planetary system | 2 planets |
Atmospheric parameters
Temperatures
| Data Source | Type | Result Value | Result Figure | Notes | Reference |
Molecules
| Molecule | Data Source | Type | Result Value | Result Figure | Notes | Reference |
| CH4 | Measurements | Detected | 2020 - MADHUSUDHAN N. | |||
| H2O | Measurements | Detected | 2020 - MADHUSUDHAN N. | |||
| Measurements | Detected | 2019 - BENNEKE B. | ||||
| Measurements | Detected | 2019 - TSIARAS A. | ||||
| NH3 | Measurements | Detected | 2020 - MADHUSUDHAN N. | |||
Observability Predictor 
Related publications
Consistently Simulating a Wide Range of Atmospheric Scenarios for K2-18b with a Flexible Radiative Transfer Module
2020
SCHEUCHER M., WUNDERLICH F., GRENFELL J., GODOLT M., SCHREIER F. et al.
ApJ., 898, 44
paper arxiv
The high-energy environment and atmospheric escape of the mini-Neptune K2-18 b
2020
dos SANTOS L., EHRENREICH D., BOURRIER V., ASTUDILLO-DEFRU N., BONFILS X. et al.
Astron. & Astrophys., 634, L4
paper arxiv
The interior and atmosphere of the habitable-zone exoplanet K2-18b
2020
MADHUSUDHAN N., NIXON M., WELBANKS L., PIETTE A. & BOOTH R.
ApJ. Letters, accepted
arxiv
Disentangling Atmospheric Compositions of K2-18 b with Next Generation Facilities
2020
CHANGEAT Q., EDWARDS B., AL-REFAIE A., TSIARAS A., WALDMANN I. & TINETTI G.
ApJ, submitted
arxiv
Formation of secondary atmospheres on terrestrial planets by late disk accretion
2020
KRAL Q., DAVOULT J. & CHARNEY B.
Nature Astronomy
paper arxiv
Tidal evolution of exoplanetary systems hosting potentially habitable exoplanets. The cases of LHS-1140 b-c and K2-18 b-c
2020
GOMES G. & FERRAZ-MELLO S.
MNRAS, 494, 5082
paper arxiv
Methane as a dominant absorber in the habitable-zone sub-Neptune K2-18 b
2020
BEZARD B., CHARNEY B. & BLAIN D.
Nature Astron., submitted
arxiv
1D atmospheric study of the temperate sub-Neptune K2-18b
2020
BLAIN D., CHARNEY B. & BEZARD B.
Astron. & Astrophys., in press
paper
On the Temperature Profiles and Emission Spectra of Mini-Neptune Atmospheres
2020
PIETTE A. & MADHUSUDHAN N.
ApJ, accepted
arxiv
The K2-18b Planetary System: Estimates of the Age and X-UV Irradiances of a Habitable Zone "Wet" Sub-Neptune Planet
2019
GUINAN E. & ENGIE S.
Res. Notes AAS, 3, 189
paper
Mass-Radius relationship for M dwarf exoplanets: Comparing nonparametric and parametric methods
2019
KANODIA Sh., WOLFGANG A., STEFANSSON G., NING B. & MAHADEVAN S.
ApJ, submitted
arxiv
Water Vapor on the Habitable-Zone Exoplanet K2-18b
2019
BENNEKE B., WONG I., PIAULET C., KNUTSON H., CROSSFIELD I. et al.
ApJ. Letters, 887, L14
paper arxiv
Water vapour in the atmosphere of the habitable-
zone eight-Earth-mass planet K2-18 b
2019
TSIARAS A., WALDMANN I., TINETTI G., TENNYSON J. & YOURCHENKO S.
Nature Astronomy, in press
paper arxiv
The weight of a world
2019
Anonymous
Nature Astronomy, 3, 875
paper
The CARMENES Search for Exoplanets around M Dwarfs: A Low-mass Planet in the Temperate Zone of the Nearby K2-18
2018
SARKIS P., HENNING Th., KÜRSTER M., TRIFONOV T., ZECHMEISTER M. et al.
Astron. J., 155, 257
arxiv
The CARMENES search for exoplanets around M dwarfs: A low-mass planet in the temperate zone of the nearby K2-18
2018
PAULA S., HENNING Th., MARTIN K., TRIFON T., ZECHMEISTER L., et al.
Astron. J., accepted
arxiv
Characterization of the K2-18 multi-planetary system with HARPS: A habitable zone super-Earth and discovery of a second, warm super-Earth on a non-coplanar orbit
2017
CLOUTIER R., ASTUDILLO-DEFRU N., DOYON R., BONFILS X., ALMENARA J. et al.
Astron. & Astrophys., 608, A35
paper arxiv
ADS
Spitzer Observations Confirm and Rescue the Habitable-Zone Super-Earth K2-18b for Future Characterization
2016
BENNEKE B., WERNER M., PETIGURA E., KNUTSON H., DRESSING C. et al.
ApJ, 834, 187
paper arxiv
ADS
Stellar and Planetary Properties of K2 Campaign 1 Candidates and Validation of 17 Systems, Including a Planet Receiving Earth-like Insolation
2015
MONTET B., MORTON T., FOREMAN-MACKEY D., JOHNSON J., HOGG D. et 4 additional authors
ApJ, 809, 25
arxiv
paper
ADS
