Registry · exoplanet

KELT-9 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: 20h 31m 26.38s
Declination: +39° 56′ 20.1″
Galactic l, b: 78.913, 0.2485
Magnitude V: 7.55
Distance: 204.46 pc

Planet

NASA Exoplanet Archive, composite parameters

Host star	KELT-9 · A
Discovery	Transit, 2017 · KELT-North
Orbital period	1.48112 d
Semi-major axis	0.03368 au
Eccentricity	0
Radius	21.701 R⊕ · 1.936 R♃
Mass	915.35 M⊕ · 2.88 M♃
Density	0.491 g/cm³
Equilibrium temperature	3,921 K
System distance	204.46 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
915.3458	M_earth	± 111.2	Transit	NASA Exoplanet Archive	Borsa et al. 2019	2019
775.5052	M_earth	± 222.5	Transit	NASA Exoplanet Archive	Hoeijmakers et al. 2019	2019
915.3504	M_earth	± 267	Transit	NASA Exoplanet Archive	Gaudi et al. 2017	2017

Radius 4 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
21.70059	R_earth	± 0.5268	Transit	NASA Exoplanet Archive	Borsa et al. 2019	2019
19.98565	R_earth	± 0.1009	Transit	NASA Exoplanet Archive	Hoeijmakers et al. 2019	2019
20.34024	R_earth	± 0.5224	Transit	NASA Exoplanet Archive	ExoFOP	2017
21.19622	R_earth	± 0.6837	Transit	NASA Exoplanet Archive	Gaudi et al. 2017	2017

Orbital period 6 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
1.481119	d	± 1.40e-07	Transit	NASA Exoplanet Archive	Kokori et al. 2023	2023
1.481119	d	± 1.60e-07	Transit	NASA Exoplanet Archive	Ivshina & Winn 2022	2022
1.481124	d	± 1.10e-06	Transit	NASA Exoplanet Archive	Wong et al. 2020	2020
1.481124	d	± 1.10e-06	Transit	NASA Exoplanet Archive	Borsa et al. 2019	2019
1.48109	d	± 3.78e-07	Transit	NASA Exoplanet Archive	ExoFOP	2017
1.481124	d	± 1.10e-06	Transit	NASA Exoplanet Archive	Gaudi et al. 2017	2017

Semi-major axis 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.03368	au	± 0.00078	Transit	NASA Exoplanet Archive	Borsa et al. 2019	2019
0.03462	au	± 0.0011	Transit	NASA Exoplanet Archive	Gaudi et al. 2017	2017

Eccentricity 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0			Transit	NASA Exoplanet Archive	Borsa et al. 2019	2019
0			Transit	NASA Exoplanet Archive	Gaudi et al. 2017	2017

Equilibrium temperature 3 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
3,921	K	± 182	Transit	NASA Exoplanet Archive	Borsa et al. 2019	2019
3,446.02	K		Transit	NASA Exoplanet Archive	ExoFOP	2017
4,050	K	± 180	Transit	NASA Exoplanet Archive	Gaudi et al. 2017	2017

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
KELT-9	Star	0″	—
HD 195689b	Planet	0.4157″	—
HD 195689	SB*	0.4157″	7.56
Gaia DR3 2064328270786091136	WhiteDwarf	160.2″	—
HD 195728	LongPeriodV* Candidate	239.4″	9.1
Gaia DR2 2064323048107085440	Star	346.2″	—
Gaia DR2 2064326449721216640	Star	429.7″	—
[BSG2004] IRAS 20293+3952 mm 3	mmRad	438.9″	—
2MASS J20311125+4003076	YSO	442.8″	—
IRAS 20293+3952	HIIReg	446.8″	—
[BSG2004] IRAS 20293+3952 mm 1	mmRad	450.3″	—

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/kelt-9-b · Registry entry updated 2026-08-14.