Registry · exoplanet

HR 8799 d

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: 23h 07m 28.84s
Declination: +21° 08′ 02.5″
Galactic l, b: 92.765, -35.58
Magnitude V: 5.98
Distance: 41.244 pc

Planet

NASA Exoplanet Archive, composite parameters

Host star	HR 8799 · A5 V
Discovery	Imaging, 2008 · W. M. Keck Observatory
Orbital period	37,000 d
Semi-major axis	24 au
Eccentricity	0.6
Radius	13 R⊕ · 1.2 R♃
Mass	3,000 M⊕ · 10 M♃
Density	7.5 g/cm³
Equilibrium temperature	1,300 K
System distance	41.244 pc

Recorded parameters

3 quantities with a single published value

Parameter	Value	Unit	Uncertainty	As published	Source	Reference
Mass	3,000	M_earth	± 1,000	Imaging	NASA Exoplanet Archive	Marois et al. 2008
Eccentricity	0.6			Imaging	NASA Exoplanet Archive	Konopacky et al. 2016
Equilibrium temperature	1,300	K		Imaging	NASA Exoplanet Archive	Bonnefoy et al. 2016

Published measurements

3 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.

Radius 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
10.0881	R_earth		Imaging	NASA Exoplanet Archive	Bonnefoy et al. 2016	2016
13	R_earth	± 1	Imaging	NASA Exoplanet Archive	Marois et al. 2008	2008

Orbital period 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
41,627.54	d	± 2,257	Imaging	NASA Exoplanet Archive	Zurlo et al. 2016	2016
37,000	d		Imaging	NASA Exoplanet Archive	Marois et al. 2008	2008

Semi-major axis 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
26.97	au	± 0.73	Imaging	NASA Exoplanet Archive	Zurlo et al. 2016	2016
24	au		Imaging	NASA Exoplanet Archive	Marois et al. 2008	2008

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
HR 8799 b	Exoplanet	0″	5.98
HR 8799 c	Exoplanet	0″	5.98
HR 8799 e	Exoplanet	0″	5.98
HR 8799	Star	0″	—
HD 218396c	Planet	1.849″	—
HD 218396e	Planet	1.849″	—
HD 218396b	Planet	1.849″	—
HD 218396	EllipVar	1.849″	5.953
HD 218396d	Planet	1.849″	—
HD 218396f	Planet Candidate	1.849″	—
SDSS J230751.89+210526.7	QSO	358.3″	—

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/hr-8799-d · Registry entry updated 2026-08-14.