Registry · exoplanet

HR 8799 c

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 · Gemini Observatory
Orbital period	69,000 d
Semi-major axis	38 au
Eccentricity	0.5
Radius	13 R⊕ · 1.2 R♃
Mass	3,000 M⊕ · 10 M♃
Density	7.5 g/cm³
Equilibrium temperature	1,200 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	0.5			Imaging	NASA Exoplanet Archive	Konopacky et al. 2016
Equilibrium temperature	1,200	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
11.209	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 3 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
83,255.09	d	± 4,511	Imaging	NASA Exoplanet Archive	Zurlo et al. 2016	2016
67,571.25	d		Imaging	NASA Exoplanet Archive	Konopacky et al. 2016	2016
69,000	d		Imaging	NASA Exoplanet Archive	Marois et al. 2008	2008

Semi-major axis 3 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
42.81	au	± 1.16	Imaging	NASA Exoplanet Archive	Zurlo et al. 2016	2016
38	au		Imaging	NASA Exoplanet Archive	Konopacky et al. 2016	2016
38	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 d	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-c · Registry entry updated 2026-08-14.