Registry · exoplanet

TRAPPIST-1 d

Exoplanet 268 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-1d

Planet

NASA Exoplanet Archive, composite parameters

Host star	TRAPPIST-1 · M7.5e
Discovery	Transit, 2016 · La Silla Observatory
Orbital period	4.04922 d
Semi-major axis	0.02227 au
Eccentricity	0.00837
Radius	0.788 R⊕ · 0.0703 R♃
Mass	0.388 M⊕ · 0.001221 M♃
Density	4.367 g/cm³
Equilibrium temperature	286.2 K
System distance	12.43 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 4 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.388	M_earth	± 0.012	Transit	NASA Exoplanet Archive	Piaulet-Ghorayeb et al. 2025	2025
0.388	M_earth	± 0.012	Transit	NASA Exoplanet Archive	Agol et al. 2021	2021
0.297	M_earth	± 0.039	Transit	NASA Exoplanet Archive	Grimm et al. 2018	2018
0.41	M_earth	± 0.27	Transit	NASA Exoplanet Archive	Gillon et al. 2017	2017

Radius 4 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.804	R_earth	± 0.014	Transit	NASA Exoplanet Archive	Piaulet-Ghorayeb et al. 2025	2025
0.788	R_earth	± 0.011	Transit	NASA Exoplanet Archive	Agol et al. 2021	2021
0.784	R_earth	± 0.023	Transit	NASA Exoplanet Archive	Grimm et al. 2018	2018
0.772	R_earth	± 0.03	Transit	NASA Exoplanet Archive	Gillon et al. 2017	2017

Orbital period 4 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
4.049219	d	± 2.60e-05	Transit	NASA Exoplanet Archive	Piaulet-Ghorayeb et al. 2025	2025
4.049219	d	± 2.60e-05	Transit	NASA Exoplanet Archive	Agol et al. 2021	2021
4.04978	d	± 2.66e-06	Transit	NASA Exoplanet Archive	Ducrot et al. 2020	2020
4.04961	d	± 6.30e-05	Transit	NASA Exoplanet Archive	Gillon et al. 2017	2017

Semi-major axis 5 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.0223	au	± 0.0003	Transit	NASA Exoplanet Archive	Piaulet-Ghorayeb et al. 2025	2025
0.02227	au	± 0.00019	Transit	NASA Exoplanet Archive	Agol et al. 2021	2021
0.02226	au	± 0.00019	Transit	NASA Exoplanet Archive	Ducrot et al. 2020	2020
0.02228038	au	± 4.40e-07	Transit	NASA Exoplanet Archive	Grimm et al. 2018	2018
0.02144	au	± 0.00066	Transit	NASA Exoplanet Archive	Gillon et al. 2017	2017

Eccentricity 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.00837		± 0.00093	Transit	NASA Exoplanet Archive	Grimm et al. 2018	2018
0.07			Transit	NASA Exoplanet Archive	Gillon et al. 2017	2017

Equilibrium temperature 3 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
286	K	± 3	Transit	NASA Exoplanet Archive	Piaulet-Ghorayeb et al. 2025	2025
286.2	K	± 2.8	Transit	NASA Exoplanet Archive	Ducrot et al. 2020	2020
288	K	± 5.6	Transit	NASA Exoplanet Archive	Gillon et al. 2017	2017

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
TRAPPIST-1 e	Exoplanet	0.003074″	17.02
TRAPPIST-1 b	Exoplanet	0.003074″	17.02
TRAPPIST-1 c	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

Archive	Read at (UTC)	Record
Seeded from the bulk archive load; no per-object fetch yet.

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