TRAPPIST-1 Overview

TRAPPIST-1 0.12 R_⦿ 3352.33 K

TRAPPIST-1 b

0.100 R_Jup

TRAPPIST-1 c

0.098 R_Jup

TRAPPIST-1 d

0.070 R_Jup

TRAPPIST-1 e

0.082 R_Jup

TRAPPIST-1 f

0.093 R_Jup

TRAPPIST-1 g

0.101 R_Jup

TRAPPIST-1 h

0.067 R_Jup

Overview Notes 3 Parameters Nearby Data Bibliography 21 Legend

Architecture: TRAPPIST-1; TRAPPIST-1

Discovery Data

Host	Planet	Orbital Separation	Planet Size	Method	Year	Reference	Disposition
TRAPPIST-1	TRAPPIST-1 b	1.51 d	1.12 R_⨁	Transit	2016	Gillon et al. 2016	Confirmed Planet
TRAPPIST-1	TRAPPIST-1 c	2.42 d	1.1 R_⨁	Transit	2016	Gillon et al. 2016	Confirmed Planet
TRAPPIST-1	TRAPPIST-1 d	4.05 d	0.79 R_⨁	Transit	2016	Gillon et al. 2016	Confirmed Planet
TRAPPIST-1	TRAPPIST-1 e	6.1 d	0.92 R_⨁	Transit	2017	Gillon et al. 2016	Confirmed Planet
TRAPPIST-1	TRAPPIST-1 f	9.21 d	1.05 R_⨁	Transit	2017	Gillon et al. 2016	Confirmed Planet
TRAPPIST-1	TRAPPIST-1 g	12.35 d	1.13 R_⨁	Transit	2017	Gillon et al. 2016	Confirmed Planet
TRAPPIST-1	TRAPPIST-1 h	18.77 d	0.76 R_⨁	Transit	2017	Gillon et al. 2016	Confirmed Planet

Exoplanet Archive Notes (3)

TRAPPIST-1

Original planet parameters for planet 'd' retracted by Gillon et al. (2017) owing to incorrect period. (Gillon et al. 2016)

TRAPPIST-1 d

Omitted semi-major axis, irradiation, equilibrium temperature, ratio of distance to stellar radius (ranges of discrete values given for set of possible periods). See Table 1 of ref. (Gillon et al. 2016)
Original planet parameters for planet 'd' retracted by Gillon et al. (2017) owing to incorrect period. (Gillon et al. 2017)

TRAPPIST-1 Stellar Parameters (9 Solutions)

RA: 23h06m30.33s

Dec: -05d02m36.46s

Distance: 12.429888806540756±0.018706614394702 pc

Parallax: 80.451242610777669±0.121076736607856 mas

Ecliptic Latitude: .62982 deg

Ecliptic Longitude: 345.73298 deg

Galactic Latitude: -56.64891 deg

Galactic Longitude: 69.71519 deg

Total Proper Motion: 1026.5792712±8.0000000 mas/yr

Proper Motion (RA): 901.0±8.0 mas/yr

Proper Motion (Dec): -492.0±8.0 mas/yr

Photometry: m_V
17.02±0.20; m_TESS
13.8529000±0.0112926; m_J
11.354±0.022; m_H
10.718±0.021; m_Ks
10.296±0.023; m_Kep
12.917; m_Ic
14.0±0.1; m_Gaia
15.645100±0.001448; m_g
19.6235000±0.0155229; m_i
15.092300±0.004339; m_r
17.996300±0.007352; m_u
23.305600±0.803622; m_z
13.4342000±0.0040633

Mission: K2 : Observed in Campaign 12

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

Source	Agol et al. 2021	Ducrot et al. 2020	Hirano et al. 2020	TICv8	Gaia DR2	Grimm et al. 2018	Gillon et al. 2017	Gillon et al. 2016	ExoFOP-TESS TOI	Show Candidate Solutions >>	<< Hide Candidate Solutions
T_eff (K)	2566±26	2520±39	---	---	3352.3333+103.6670-61.8333	---	2559±50	2550±55	5780
L_✶ (log₁₀(L_⦿))	-3.26+0.01-0.02	-3.26+0.01-0.01	---	---	---	---	-3.28+0.03-0.03	-3.28+0.03-0.03	---
Metallicity (dex)	---	0.05350±0.08800 [Fe/H]	---	---	---	---	0.040±0.080 [Fe/H]	0.040±0.080 [Fe/H]	---
Age (Gyr)	---	---	---	---	---	---	---	>0.5	---
ρ_✶ (g/cm³)	75.05+1.02-1.66	67.64±5.50	---	84.5307882±11.2901428	---	---	71.5+1.7-3.1	70.9+8.0-4.6	---
M_✶ (M_⦿)	0.0898±0.0023	0.0898±0.0023	---	0.09077820±0.02000690	---	0.089±0.007	0.0802±0.0073	0.080±0.009	---
R_✶ (R_⦿)	0.1192±0.0013	0.1234±0.0033	---	0.1148270±0.0033573	---	---	0.1170±0.0036	0.117±0.004	0.114826999604702±0.003357280000000
P_rot (days)	---	---	---	---	---	---	---	1.40±0.05	---
log g (log₁₀(cm/s²))	5.2396+0.0056-0.0073	---	---	5.2759600±0.0719093	---	---	---	---	5.2759600±0.0719093
v sin i (km/s)	---	---	2.04+0.18-0.16	---	---	---	---	---	---

TRAPPIST-1 b Planetary Parameters (9 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

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

Source	Agol et al. 2021	Rathcke et al. 2025	Ducrot et al. 2020	Hirano et al. 2020	Grimm et al. 2018	Gillon et al. 2017	de Wit et al. 2016	Gillon et al. 2016	ExoFOP-TESS TOI	Show Candidate Solutions >>	<< Hide Candidate Solutions
a/R_✶	20.843+0.094-0.155	20.802+0.052-0.078	20.13+0.46-0.55	---	---	20.50+0.16-0.31	---	20.45+0.43-0.81	---
ω (deg)	---	90	---	---	336.86±34.24	---	---	---	---
e	---	0	---	---	0.00622±0.00304	<0.081	---	0	---
i (deg)	89.728±0.165	89.80+0.14-0.12	89.28±0.32	---	---	89.65+0.22-0.27	89.39±0.32	89.41±0.41	---
P (days)	1.510826±0.000006	1.5108261±0.0000058	1.51088432±0.00000015	1.51087+0.00022-0.00017	---	1.51087081±0.00000060	---	1.510848±0.000019	1.51094471179194±0.00012604707000
R_p/R_✶	0.08590±0.00037	0.08507+0.00016-0.00017	---	---	---	---	---	---	---
T_C (days)	---	2460501.405464+0.000010-0.000011 (BJD-TDB)	2457322.514193±0.000003 (BJD-TDB)	2458362.0021+0.0016-0.0022 (BJD-TDB)	---	2457322.51736±0.00010 (BJD-TDB)	2457512.88646±0.00030 (BJD)	2457322.51765±0.00025 (BJD-TDB)	2460209.80835200±0.00109332 (BJD)
T_eq (K)	---	---	397.6±3.8	---	---	400.1±7.7	366	400±9	802.860220389002
δ (%)	0.7378±0.0064	---	---	---	---	0.7266±0.0088	0.8015±0.0220	0.754±0.025	1.06934881603416±0.11801766000000
T₁₄ (hours)	0.6010±0.0018	---	0.60515±0.00155	---	---	0.6067±0.0028	0.6020±0.0077	0.6020±0.0077	0.640149871039871±0.125401200000000
b	0.0950+0.0650-0.0610	---	0.254+0.110-0.085	---	---	0.126+0.092-0.078	---	0.21±0.14	---
S (S_⨁)	4.153+0.161-0.159	---	4.15±0.16	---	---	4.25±0.33	---	4.25±0.38	98.1930529305747
M_p (M_⨁)	1.374±0.069	---	---	---	1.017+0.154-0.143	0.850±0.720	---	---	---
M_p (M_Jup)	0.004323±0.000217	---	---	---	0.003200+0.000485-0.000450	0.00267±0.00227	---	---	---
ρ (g/cm³)	5.442+0.265-0.276	---	---	---	4.00+0.51-0.50	3.6±3.1	---	---	---
R_p (R_⨁)	1.116+0.014-0.012	---	---	---	1.121+0.031-0.032	1.086±0.035	---	1.113±0.044	1.20389171822242±0.23403676000000
R_p (R_Jup)	0.09956+0.00125-0.00107	---	---	---	0.1000+0.0028-0.0029	0.09689±0.00312	---	0.09930±0.00393	0.107404210110061±0.020879397178371
a (au)	0.01154±0.00010	---	0.011534+0.000099-0.000092	---	0.011547750±0.000000057	0.01111±0.00034	---	0.01111±0.00040	---
λ (deg)	---	---	---	15+26-30	---	---	---	---	---

TRAPPIST-1 c Planetary Parameters (7 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

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

Source	Agol et al. 2021	Rathcke et al. 2025	Ducrot et al. 2020	Grimm et al. 2018	Gillon et al. 2017	de Wit et al. 2016	Gillon et al. 2016
a/R_✶	28.549+0.129-0.212	28.422+0.073-0.111	27.57+0.62-0.76	---	28.08+0.22-0.42	---	28.0+0.6-1.1
ω (deg)	---	90	---	282.45±17.10	---	---	---
e	---	0	---	0.00654±0.00188	<0.083	---	0
i (deg)	89.778±0.118	89.83761834+0.09000000-0.08000000	89.47±0.24	---	89.67±0.17	89.58±0.11	89.50±0.31
P (days)	2.421937±0.000018	2.4219371+0.0000180-0.0000179	2.42179346±0.00000023	---	2.4218233±0.0000017	---	2.421848±0.000028
R_p/R_✶	0.08440±0.00038	0.08453+0.00016-0.00017	---	---	---	---	---
T_C (days)	---	2460501.385348+0.000011-0.000012 (BJD-TDB)	2457282.8113871±0.0000038 (BJD-TDB)	---	2457282.80728±0.00019 (BJD-TDB)	2457512.88019±0.00016 (BJD)	2457362.72618±0.00033 (BJD-TDB)
T_eq (K)	---	---	339.7±3.3	---	341.9±6.6	315	342±8
δ (%)	0.7123±0.0064	---	---	---	0.687±0.010	0.7290±0.0240	0.672±0.042
T₁₄ (hours)	0.7005±0.0022	---	0.707±0.002	---	0.7062±0.0037	0.6963±0.0135	0.6963±0.0135
b	0.109+0.059-0.061	---	0.254+0.110-0.087	---	0.161+0.076-0.084	---	0.25±0.15
S (S_⨁)	2.214+0.086-0.085	---	2.211±0.085	---	2.27±0.18	---	2.26±0.21
M_p (M_⨁)	1.308±0.056	---	---	1.156+0.142-0.131	1.38±0.61	---	---
M_p (M_Jup)	0.004115±0.000176	---	---	0.003637+0.000447-0.000412	0.00434±0.00192	---	---
ρ (g/cm³)	5.464+0.221-0.237	---	---	4.87+0.46-0.43	6.45±2.92	---	---
R_p (R_⨁)	1.097+0.014-0.012	---	---	1.095+0.030-0.031	1.056±0.035	---	1.049±0.050
R_p (R_Jup)	0.09787+0.00125-0.00107	---	---	0.09769+0.00268-0.00277	0.09421±0.00312	---	0.09359±0.00446
a (au)	0.01580±0.00013	---	0.01579+0.00014-0.00013	0.01581512±0.00000015	0.01521±0.00047	---	0.01522±0.00055

TRAPPIST-1 d Planetary Parameters (4 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

Tools: Planetary Systems; Transit Prediction Service; K2 Names; K2 Planets and Candidates; Transit

Source	Agol et al. 2021	Ducrot et al. 2020	Grimm et al. 2018	Gillon et al. 2017
a/R_✶	40.216+0.182-0.299	38.85+0.88-1.10	---	39.55+0.30-0.59
b	0.0630+0.0630-0.0430	0.235+0.120-0.094	---	0.17±0.11
S (S_⨁)	1.115±0.043	1.114±0.043	---	1.143±0.088
M_p (M_⨁)	0.388±0.012	---	0.297+0.039-0.035	0.41±0.27
M_p (M_Jup)	0.00122±0.00004	---	0.000934+0.000123-0.000110	0.0013±0.0008
i (deg)	89.896±0.077	89.65±0.15	---	89.75±0.16
P (days)	4.049219±0.000026	4.04978035±0.00000266	---	4.049610±0.000063
ρ (g/cm³)	4.37+0.15-0.17	---	3.40+0.37-0.34	4.9±3.3
R_p (R_⨁)	0.788+0.011-0.010	---	0.784±0.023	0.772±0.030
R_p (R_Jup)	0.0703+0.0010-0.0009	---	0.0699±0.0021	0.0689±0.0027
R_p/R_✶	0.06063±0.00052	---	---	---
a (au)	0.02227±0.00019	0.02226+0.00019-0.00018	0.02228038±0.00000044	0.02144+0.00066-0.00063
δ (%)	0.3676±0.0063	---	---	0.367±0.017
T₁₄ (hours)	0.8145±0.0040	0.8228±0.0053	---	0.8188±0.0110
ω (deg)	---	---	-8.73±6.17	---
e	---	---	0.00837±0.00093	<0.070
T_eq (K)	---	286.2±2.8	---	288.0±5.6
T_C (days)	---	2457670.1463014±0.0000184 (BJD-TDB)	---	2457670.14165±0.00035 (BJD-TDB)

TRAPPIST-1 e Planetary Parameters (5 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

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

Source	Agol et al. 2021	Ducrot et al. 2020	Hirano et al. 2020	Grimm et al. 2018	Gillon et al. 2017
a/R_✶	52.855+0.239-0.392	51.0+1.2-1.4	---	---	51.97+0.40-0.77
b	0.191±0.041	0.299+0.085-0.072	---	---	0.12+0.11-0.09
S (S_⨁)	0.646±0.025	0.645±0.025	---	---	0.662±0.051
M_p (M_⨁)	0.692±0.022	---	---	0.772+0.079-0.075	0.62±0.58
M_p (M_Jup)	0.00218±0.00007	---	---	0.00243+0.00025-0.00024	0.0020±0.0018
i (deg)	89.793±0.048	89.663±0.092	---	---	89.86+0.10-0.12
P (days)	6.101013±0.000035	6.09956479±0.00000178	6.09705+0.00096-0.00093	---	6.099615±0.000011
ρ (g/cm³)	4.90+0.17-0.18	---	---	5.646+0.419-0.386	4.4±4.2
R_p (R_⨁)	0.920+0.013-0.012	---	---	0.910+0.026-0.027	0.918±0.039
R_p (R_Jup)	0.0821+0.0012-0.0011	---	---	0.0812+0.0023-0.0024	0.0819±0.0035
R_p/R_✶	0.07079±0.00055	---	---	---	---
a (au)	0.02925±0.00250	0.02924+0.00025-0.00023	---	0.02928285±0.00000034	0.02817+0.00083-0.00087
δ (%)	0.5012±0.0078	---	---	---	0.519±0.026
T₁₄ (hours)	0.9293±0.0043	0.9385±0.0042	---	---	0.9535±0.0120
ω (deg)	---	---	---	108.37±8.47	---
e	---	---	---	0.00510±0.00058	<0.085
T_eq (K)	---	249.7±2.4	---	---	251.3±4.9
T_C (days)	---	2457660.3676621±0.0000143 (BJD-TDB)	2458361.8113+0.0028-0.0025 (BJD-TDB)	---	2457660.37859±0.00038 (BJD-TDB)
λ (deg)	---	---	9.0+45.0-51.0	---	---

TRAPPIST-1 f Planetary Parameters (5 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

Tools: Planetary Systems; Transit Prediction Service; K2 Names; K2 Planets and Candidates; Transit

Source	Agol et al. 2021	Ducrot et al. 2020	Hirano et al. 2020	Grimm et al. 2018	Gillon et al. 2017
a/R_✶	69.543+0.314-0.516	67.10+1.15-1.90	---	---	68.4+0.5-1.0
b	0.312+0.023-0.018	0.391±0.056	---	---	0.382±0.035
S (S_⨁)	0.373+0.015-0.014	0.373±0.014	---	---	0.382±0.030
M_p (M_⨁)	1.039±0.031	---	---	0.9340+0.0800-0.0780	0.68±0.18
M_p (M_Jup)	0.003269±0.000098	---	---	0.002939+0.000252-0.000245	0.0021±0.0006
i (deg)	89.740±0.019	89.666±0.059	---	---	89.680±0.034
P (days)	9.207540±0.000032	9.20659399±0.00000212	9.2129±0.0010	---	9.206690±0.000015
ρ (g/cm³)	5.02+0.14-0.16	---	---	4.50+0.21-0.20	3.30±0.94
R_p (R_⨁)	1.045+0.013-0.012	---	---	1.046+0.029-0.030	1.045±0.038
R_p (R_Jup)	0.09323+0.00116-0.00107	---	---	0.09332+0.00259-0.00268	0.09323±0.00339
R_p/R_✶	0.08040±0.00047	---	---	---	---
a (au)	0.03849±0.00033	0.038774+0.000330-0.000310	---	0.03853361±0.00000048	0.0371±0.0011
δ (%)	0.6465±0.0076	---	---	---	0.673±0.023
T₁₄ (hours)	1.0480±0.0042	1.055±0.005	---	---	1.043±0.010
ω (deg)	---	---	---	368.81±3.11	---
e	---	---	---	0.01007±0.00068	<0.063
T_eq (K)	---	217.7±2.1	---	---	219.0±4.2
T_C (days)	---	2457671.3737299±0.0000157 (BJD-TDB)	2458361.8545±0.0018 (BJD-TDB)	---	2457671.39767±0.00023 (BJD-TDB)
λ (deg)	---	---	21±32	---	---

TRAPPIST-1 g Planetary Parameters (4 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

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

Source	Agol et al. 2021	Ducrot et al. 2020	Grimm et al. 2018	Gillon et al. 2017
a/R_✶	84.591+0.382-0.628	81.7+1.8-2.3	---	83.2+0.6-1.2
b	0.379+0.018-0.014	0.430±0.049	---	0.421±0.031
S (S_⨁)	0.252±0.010	0.2520±0.0097	---	0.258±0.020
M_p (M_⨁)	1.321±0.038	---	1.148+0.098-0.095	1.34±0.88
M_p (M_Jup)	0.004156±0.000120	---	0.003612+0.000308-0.000299	0.00422±0.00277
i (deg)	89.742±0.012	89.698±0.044	---	89.710±0.025
P (days)	12.352446±0.000054	12.35355570±0.00000341	---	12.35294±0.00012
ρ (g/cm³)	5.06+0.14-0.16	---	4.18+0.19-0.18	5.2±3.5
R_p (R_⨁)	1.129+0.015-0.013	---	1.148+0.032-0.033	1.127±0.041
R_p (R_Jup)	0.1007+0.0013-0.0012	---	0.1024+0.0029-0.0029	0.1005±0.0037
R_p/R_✶	0.08692±0.00053	---	---	---
a (au)	0.04683±0.00040	0.04681528+0.00040000-0.00037000	0.04687692±0.00000032	0.0451±0.0014
δ (%)	0.7555±0.0092	---	---	0.782±0.027
T₁₄ (hours)	1.1370±0.0047	1.152±0.006	---	1.140±0.011
ω (deg)	---	---	191.34±13.83	---
e	---	---	0.00208±0.00058	<0.061
T_eq (K)	---	197.3±1.9	---	198.6±3.8
T_C (days)	---	2457665.3628439±0.0000206 (BJD-TDB)	---	2457665.34937±0.00021 (BJD-TDB)

TRAPPIST-1 h Planetary Parameters (5 Solutions)

Status: Confirmed Planet

Detected By: Transit Timing Variations, Transit

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

Source	Agol et al. 2021	Ducrot et al. 2020	Grimm et al. 2018	Luger et al. 2017	Gillon et al. 2017
a/R_✶	111.817+0.505-0.830	107.9+2.4-3.0	---	109±4	117+50-26
b	0.378+0.024-0.023	0.448±0.054	---	0.45+0.06-0.08	0.45+0.22-0.29
S (S_⨁)	0.144±0.006	0.1440±0.0055	---	0.165±0.025	0.131+0.081-0.067
M_p (M_⨁)	0.326±0.020	---	0.331+0.056-0.049	---	---
M_p (M_Jup)	0.00103±0.00006	---	0.00104+0.00018-0.00015	---	---
i (deg)	89.805±0.013	89.763±0.037	---	89.76+0.05-0.04	89.80+0.10-0.05
P (days)	18.772866±0.000214	18.76727450±0.00001876	---	18.767+0.004-0.003	20+15-6
ρ (g/cm³)	4.16+0.33-0.30	---	3.96+0.65-0.56	---	---
R_p (R_⨁)	0.755±0.014	---	0.773+0.026-0.027	0.752+0.032-0.031	0.755±0.034
R_p (R_Jup)	0.0674±0.0012	---	0.0690+0.0023-0.0024	0.0671+0.0029-0.0028	0.0674±0.0030
R_p/R_✶	0.05809±0.00087	---	---	0.0588±0.0016	---
a (au)	0.06189±0.00053	0.0618656+0.0005300-0.0004900	0.06193488±0.00000080	---	0.063+0.027-0.013
δ (%)	0.3375±0.0101	---	---	0.346±0.018	0.3520±0.0326
T₁₄ (hours)	1.2690±0.0093	1.271±0.014	---	1.26±0.02	1.280+0.045-0.033
ω (deg)	---	---	338.92±9.66	---	---
e	---	---	0.00567±0.00121	---	---
T_eq (K)	---	171.7±1.7	---	173±4	168+21-28
T_C (days)	---	2457662.5741486±0.0000913 (BJD-TDB)	---	2457662.55284±0.00037 (BJD-TDB)	2457662.55463±0.00056 (BJD-TDB)