K2-18 Overview

K2-18 0.40 R_⦿ 3496.00 K

K2-18 c

K2-18 b

0.211 R_Jup

Overview Notes System Parameters Nearby Data Legend

Architecture: K2-18; K2-18

Other Data: Bibliography 14; Exoplanet Archive Notes 4; Nearby Data 5

Discovery Data

Host	Planet	Method	Year	Reference	Disposition
K2-18	K2-18 c	Radial Velocity	2017	Cloutier et al. 2017	Confirmed Planet
K2-18	K2-18 b	Transit	2015	Montet et al. 2015	Confirmed Planet

Exoplanet Archive Notes (4)

K2-18

Rotation period uncertainty calculated as average from asymmetric uncertainties. (Cloutier et al. 2017)

K2-18 c

Equilibrium temperature was calculated assuming a Bond albedo of 0.3. (Cloutier et al. 2017)
Planet flagged as controversial. (Sarkis et al. 2018)

K2-18 b

Equilibrium temperature was calculated assuming a Bond albedo of 0.3. Time of inferior conjunction entered under mid-transit time. (Cloutier et al. 2017)

K2-18 Stellar Parameters (12 Solutions)

RA: 11h30m14.43s

Dec: +07d35m16.19s

Distance: 38.02660±0.07955 pc

Parallax: 26.2686000±0.0545906 mas

Ecliptic Latitude: 4.01942 deg

Ecliptic Longitude: 170.16732 deg

Galactic Latitude: 62.57509 deg

Galactic Longitude: 254.63265 deg

Total Proper Motion: 155.5222618±0.0691090 mas/yr

Proper Motion (RA): -80.3765000±0.0834003 mas/yr

Proper Motion (Dec): -133.142000±0.063101 mas/yr

Photometry: m_V
13.477±0.042; m_TESS
11.2373000±0.0073698; m_J
9.763±0.028; m_H
9.135±0.026; m_Ks
8.899±0.019; m_Kep
12.473; m_W1
8.769±0.023; m_W2
8.668±0.020; m_W3
8.552±0.025; m_W4
8.587±0.379; m_Gaia
12.415400±0.000502; m_B
14.991±0.032; m_g
15.1354000±0.0045191; m_i
11.8579000±0.0008067; m_r
13.0855000±0.0021847; m_u
16.7222000±0.0085568; m_z
11.5166000±0.0043013

Abundances (Hypatia Catalog): [Fe/H] -0.02±0.04 dex

Mission: K2 : Observed in Campaign 1

Tools: ExoFOP Target Overview Page; IRSA Finding Chart; TOI; K2 Names; K2 Planets and Candidates; K2 Targets; Stellar Hosts; K2 Time Series

Source	Benneke et al. 2019	TICv8	Gaia DR2	Sarkis et al. 2018	Cloutier et al. 2017	Benneke et al. 2017	Crossfield et al. 2016	Montet et al. 2015	Kruse et al. 2019	ExoFOP-TESS TOI	Barros et al. 2016	Vanderburg et al. 2016	Show Candidate Solutions >>	<< Hide Candidate Solutions
T_eff (K)	3457±39	3464.0±157.0	3856.180+289.595-245.180	3457±39	3457±39	3457±39	3496±91	3503±60	---	3464±157	---	3440
M_✶ (M_⦿)	0.4951±0.0043	0.440668±0.020249	---	0.359±0.047	0.359±0.047	0.359±0.047	0.420±0.070	0.413±0.043	---	---	---	---
R_✶ (R_⦿)	0.4445±0.0148	0.4445160±0.0131784	---	0.411±0.038	0.411±0.038	0.411±0.038	0.400±0.060	0.394±0.038	0.249 +0.050-0.027	0.444516003131866±0.013178400000000	---	0.36
log g (log₁₀(cm/s²))	---	4.7864000±0.0057881	---	---	---	---	4.858±0.062	---	---	4.78640000±0.00578809	---	---
Metallicity (dex)	---	---	---	0.12±0.16 [Fe/H]	---	0.123±0.157 [Fe/H]	---	0.090±0.090 [Fe/H]	---	---	---	---
ρ_✶ (g/cm³)	---	7.0731831±0.3041996	---	---	---	7.87±1.26	---	---	---	---	---	---
Sp. T	---	---	---	---	---	M2.5 V	---	---	---	---	---	---
γ (km/s)	---	---	---	---	0.6537±0.0009	---	---	---	---	---	---	---
P_rot (days)	---	---	---	39.63±0.50	38.6±0.5	---	---	---	---	---	---	---
L_✶ (log₁₀(L_⦿))	-1.60+0.03-0.04	-1.59122+0.09407-0.12025	---	---	---	---	---	---	---	---	---	---

K2-18 c Planetary Parameters (1 Solutions)

Status: Confirmed Planet
Detected By: Radial Velocity

Tools: K2 Names; K2 Planets and Candidates

Source	Cloutier et al. 2017
T_eq (K)	363±14
M_p sin i (M_⨁)	7.51±1.33
M_p sin i (M_Jup)	0.0236±0.0042
e	<0.47
P (days)	8.962±0.008
K (m/s)	4.63±0.72
a (au)	0.060±0.003

K2-18 b Planetary Parameters (10 Solutions)

Status: Confirmed Planet
Detected By: Radial Velocity, Transit

Tools: Transit Prediction Service; TOI; K2 Names; K2 Planets and Candidates; Transit; Atmospheric Spectroscopy

Source	Sarkis et al. 2018	Benneke et al. 2019	Cloutier et al. 2017	Benneke et al. 2017	Crossfield et al. 2016	Montet et al. 2015	Kruse et al. 2019	ExoFOP-TESS TOI	Barros et al. 2016	Vanderburg et al. 2016	Show Candidate Solutions >>	<< Hide Candidate Solutions
T_eq (K)	284±15	254.9±3.9	235±9	---	---	272±15	---	260.43958938777	---	---
S (S_⨁)	---	1.005+0.084-0.079	---	1.05+0.22-0.20	0.950±0.320	---	---	1.08729905250563	---	---
P (days)	32.939623+0.000095-0.000100	32.940045±0.000010	32.93963±0.00010	32.939614+0.000101-0.000084	32.9418±0.0021	32.94488±0.00281	32.94171 +0.00080-0.00084	32.9381557116336±0.0031239537000	32.92801934	32.947328
R_p (R_⨁)	2.37±0.22	2.610±0.087	2.38±0.22	2.279+0.026-0.025	2.28±0.36	2.24±0.23	1.40 +0.29-0.18	2.53224082503662±0.80855167000000	---	2.17
R_p (R_Jup)	0.211±0.020	0.2328±0.0078	0.212±0.020	0.2033+0.0023-0.0022	0.203±0.032	0.200±0.021	0.12 +0.026-0.016	0.225911783846378±0.072134272655140	---	0.194
δ (%)	---	---	---	---	---	0.285	0.3098 +0.0062-0.0065	0.321785640649977±0.025311072000000	0.354±0.021	0.311
T₁₄ (hours)	---	---	---	2.663+0.023-0.027	2.682±0.000	---	2.62800+0.05520-0.06720	2.29320234488289±0.40400365000000	3.77600+0.25600-0.25600	2.97000
T_C (days)	2457264.39144±0.00065	2457725.551189+0.000067-0.000068	2457264.39157±0.00059	2457264.39144+0.00059-0.00066	2456836.1719±0.0011	2456836.1849±0.0027	2456836.17194 +0.00059-0.00064	2459537.24962400±0.00227622	2456836.179795	2456836.171
R_p/R_✶	---	0.05375±0.00012	---	0.05295+0.00061-0.00059	0.0517±0.0021	---	0.0517 +0.0017-0.0038	---	---	0.05389
a (au)	0.1429+0.0060-0.0065	0.15910+0.00046-0.00047	0.143±0.006	0.1429+0.0060-0.0065	0.1506±0.0084	0.1491±0.0055	---	---	---	---
M_p (M_⨁)	8.920+1.700-1.600	8.63±1.35	7.96±1.91	---	---	---	---	---	---	---
M_p (M_Jup)	0.02807+0.00535-0.00503	0.0272±0.0042	0.0250±0.0060	---	---	---	---	---	---	---
e	0.20±0.08	---	<0.43	0	---	---	---	---	---	---
i (deg)	---	---	89.5785+0.0079-0.0088	89.5785+0.0079-0.0088	---	---	---	---	---	---
ρ (g/cm³)	4.11+1.72-1.18	2.67+0.52-0.47	3.3±1.2	---	---	---	---	---	---	---
K (m/s)	3.55+0.57-0.58	---	3.18±0.71	---	---	---	---	---	---	---
b	---	0.641±0.015	---	0.601+0.013-0.011	---	---	---	---	---	0.68
a/R_✶	---	---	---	---	---	83.83±9.03	94.3 +14.6-6.6	---	---	---
ω (deg)	-5.70+46.40-33.80	---	---	---	---	---	---	---	---	---