Registry · exoplanet

WASP-121 b

Exoplanet

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: 07h 10m 24.06s
Declination: −39° 05′ 50.2″
Galactic l, b: 250.29, -13.33
Magnitude V: 10.51
Distance: 269.9 pc

Planet

NASA Exoplanet Archive, composite parameters

Host star	WASP-121 · F6 V
Discovery	Transit, 2016 · SuperWASP
Orbital period	1.27493 d
Semi-major axis	0.02571 au
Eccentricity	0.0085
Radius	19.526 R⊕ · 1.742 R♃
Mass	371.86 M⊕ · 1.17 M♃
Density	0.275 g/cm³
Equilibrium temperature	2,409 K
System distance	269.9 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

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
371.8592	M_earth	± 13.67	Transit	NASA Exoplanet Archive	Sing et al. 2024	2024
367.7275	M_earth	± 22.25	Transit	NASA Exoplanet Archive	Bourrier et al. 2020	2020
375.9929	M_earth	± 20.34	Transit	NASA Exoplanet Archive	Delrez et al. 2016	2016

Radius 6 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
19.52604	R_earth	± 0.06725	Transit	NASA Exoplanet Archive	Sing et al. 2024	2024
19.64934	R_earth	± 0.4035	Transit	NASA Exoplanet Archive	Bourrier et al. 2020	2020
20.1762	R_earth		Transit	NASA Exoplanet Archive	Mikal-Evans et al. 2019	2019
18.98805	R_earth		Transit	NASA Exoplanet Archive	Evans et al. 2017	2017
22.0328	R_earth	± 0.877	Transit	NASA Exoplanet Archive	ExoFOP	2016
20.90479	R_earth	± 0.4932	Transit	NASA Exoplanet Archive	Delrez et al. 2016	2016

Orbital period 10 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
1.274925	d	± 1.50e-07	Transit	NASA Exoplanet Archive	Sing et al. 2024	2024
1.274925	d	± 4.60e-08	Transit	NASA Exoplanet Archive	Kokori et al. 2023	2023
1.274925	d	± 1.10e-07	Transit	NASA Exoplanet Archive	Ivshina & Winn 2022	2022
1.274925	d	± 1.20e-07	Transit	NASA Exoplanet Archive	Kokori et al. 2022	2022
1.274925	d	± 1.00e-07	Transit	NASA Exoplanet Archive	Patel & Espinoza 2022	2022
1.274925	d	± 1.50e-07	Transit	NASA Exoplanet Archive	Bourrier et al. 2020	2020
1.274925	d		Transit	NASA Exoplanet Archive	Mikal-Evans et al. 2019	2019
1.274925	d		Transit	NASA Exoplanet Archive	Evans et al. 2017	2017
1.274925	d	± 3.00e-07	Transit	NASA Exoplanet Archive	ExoFOP	2016
1.274925	d	± 2.00e-07	Transit	NASA Exoplanet Archive	Delrez et al. 2016	2016

Semi-major axis 4 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.02571	au	± 0.0001	Transit	NASA Exoplanet Archive	Sing et al. 2024	2024
0.02596	au	± 0.00043	Transit	NASA Exoplanet Archive	Bourrier et al. 2020	2020
0.025	au		Transit	NASA Exoplanet Archive	Mikal-Evans et al. 2019	2019
0.02544	au	± 0.00049	Transit	NASA Exoplanet Archive	Delrez et al. 2016	2016

Eccentricity 4 values

Value	Uncertainty	Band / method	Source	Reference	Year
0.0085	± 0.0013	Transit	NASA Exoplanet Archive	Pelletier et al. 2026	2026
0		Transit	NASA Exoplanet Archive	Bourrier et al. 2020	2020
0		Transit	NASA Exoplanet Archive	Evans et al. 2017	2017
0		Transit	NASA Exoplanet Archive	Delrez et al. 2016	2016

Equilibrium temperature 4 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
2,409	K	± 24	Transit	NASA Exoplanet Archive	Sing et al. 2024	2024
2,720	K	± 8	Transit	NASA Exoplanet Archive	Mikal-Evans et al. 2019	2019
2,473	K		Transit	NASA Exoplanet Archive	ExoFOP	2016
2,358	K	± 52	Transit	NASA Exoplanet Archive	Delrez et al. 2016	2016

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
WASP-121	Star	0″	—
CD-38 3220	Star	0.4016″	10.51
CD-38 3220b	Planet	0.4016″	—
CD-38 3219	Star	116.5″	11.72
HD 55273	Star	167.3″	10.1
2MASS J07102967-3901412	AGN	257.4″	—
TYC 7630-26-1	Star	389.1″	10.77
UCAC2 14986295	Star	434.5″	12.23

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/wasp-121-b · Registry entry updated 2026-08-14.