UPSA Object Registry
Registry · exoplanet

TRAPPIST-1 b

Exoplanet 396 papers
harvesting The full record is being pulled from the archives right now — measurement tables, the Gaia row, catalogue photometry. This page will fill itself in.
Right ascension
23h 06m 30.33s
Declination
−05° 02′ 36.5″
Galactic l, b
69.715, -56.65
Magnitude V
17.02
Distance
12.43 pc

Also known as

1 identifiers

TRAPPIST-1b

Planet

NASA Exoplanet Archive, composite parameters
Host starTRAPPIST-1 · M7.5e
DiscoveryTransit, 2016 · La Silla Observatory
Orbital period1.51083 d
Semi-major axis0.01154 au
Eccentricity0.00622
Radius1.116 R⊕ · 0.09956 R♃
Mass1.374 M⊕ · 0.004323 M♃
Density5.442 g/cm³
Equilibrium temperature397.6 K
System distance12.43 pc

Published measurements

6 quantities measured more than once
One object can carry a dozen published estimates of the same quantity. The register keeps them side by side rather than picking a winner — the citation is part of the value.

Mass 3 values

ValueUnitUncertainty Band / methodSourceReferenceYear
1.374 M_earth ± 0.069 Transit NASA Exoplanet Archive Agol et al. 2021 2021
1.017 M_earth ± 0.154 Transit NASA Exoplanet Archive Grimm et al. 2018 2018
0.85 M_earth ± 0.72 Transit NASA Exoplanet Archive Gillon et al. 2017 2017

Radius 5 values

ValueUnitUncertainty Band / methodSourceReferenceYear
1.116 R_earth ± 0.014 Transit NASA Exoplanet Archive Agol et al. 2021 2021
1.121 R_earth ± 0.031 Transit NASA Exoplanet Archive Grimm et al. 2018 2018
1.086 R_earth ± 0.035 Transit NASA Exoplanet Archive Gillon et al. 2017 2017
1.113 R_earth ± 0.044 Transit NASA Exoplanet Archive Gillon et al. 2016 2016
1.203892 R_earth ± 0.234 Transit NASA Exoplanet Archive ExoFOP 2016

Orbital period 7 values

ValueUnitUncertainty Band / methodSourceReferenceYear
1.510826 d ± 5.80e-06 Transit NASA Exoplanet Archive Rathcke et al. 2025 2025
1.510826 d ± 6.00e-06 Transit NASA Exoplanet Archive Agol et al. 2021 2021
1.51087 d ± 0.00022 Transit NASA Exoplanet Archive Hirano et al. 2020 2020
1.510884 d ± 1.50e-07 Transit NASA Exoplanet Archive Ducrot et al. 2020 2020
1.510871 d ± 6.00e-07 Transit NASA Exoplanet Archive Gillon et al. 2017 2017
1.510848 d ± 1.90e-05 Transit NASA Exoplanet Archive Gillon et al. 2016 2016
1.510945 d ± 0.000126 Transit NASA Exoplanet Archive ExoFOP 2016

Semi-major axis 5 values

ValueUnitUncertainty Band / methodSourceReferenceYear
0.01154 au ± 0.0001 Transit NASA Exoplanet Archive Agol et al. 2021 2021
0.011534 au ± 9.90e-05 Transit NASA Exoplanet Archive Ducrot et al. 2020 2020
0.01154775 au ± 5.70e-08 Transit NASA Exoplanet Archive Grimm et al. 2018 2018
0.01111 au ± 0.00034 Transit NASA Exoplanet Archive Gillon et al. 2017 2017
0.01111 au ± 0.0004 Transit NASA Exoplanet Archive Gillon et al. 2016 2016

Eccentricity 4 values

ValueUnitUncertainty Band / methodSourceReferenceYear
0 Transit NASA Exoplanet Archive Rathcke et al. 2025 2025
0.00622 ± 0.00304 Transit NASA Exoplanet Archive Grimm et al. 2018 2018
0.081 Transit NASA Exoplanet Archive Gillon et al. 2017 2017
0 Transit NASA Exoplanet Archive Gillon et al. 2016 2016

Equilibrium temperature 5 values

ValueUnitUncertainty Band / methodSourceReferenceYear
397.6 K ± 3.8 Transit NASA Exoplanet Archive Ducrot et al. 2020 2020
400.1 K ± 7.7 Transit NASA Exoplanet Archive Gillon et al. 2017 2017
400 K ± 9 Transit NASA Exoplanet Archive Gillon et al. 2016 2016
366 K Transit NASA Exoplanet Archive de Wit et al. 2016 2016
802.86 K Transit NASA Exoplanet Archive ExoFOP 2016

In the same field

within 9 arcmin · wider search
ObjectTypeSeparationV
TRAPPIST-1 e Exoplanet 0.003074″ 17.02
TRAPPIST-1 c Exoplanet 0.003074″ 17.02
TRAPPIST-1 d Exoplanet 0.003074″ 17.02
TRAPPIST-1 f Exoplanet 0.003074″ 17.02
TRAPPIST-1 g Exoplanet 0.003074″ 17.02
TRAPPIST-1 h Exoplanet 0.003074″ 17.02
TRAPPIST-1 Low-Mass* 16.23″ 18.8
4C -05.95 Blazar 280.4″ 19.5

Provenance

where this card came from
ArchiveRead at (UTC)Record
Seeded from the bulk archive load; no per-object fetch yet.

Machine-readable: /api/v1/object/trappist-1-b · Registry entry updated 2026-08-14.