Registry · exoplanet

16 Cyg B 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: 19h 41m 51.75s
Declination: +50° 31′ 00.6″
Galactic l, b: 83.336, 13.2
Magnitude V: 6.215
Distance: 21.14 pc

Planet

NASA Exoplanet Archive, composite parameters

Host star	16 Cyg B · G3 V
Discovery	Radial Velocity, 1996 · Multiple Observatories
Orbital period	798.5 d
Semi-major axis	1.66 au
Eccentricity	0.68
Radius	13.5 R⊕ · 1.2 R♃
Mass	565.74 M⊕ · 1.78 M♃
Density	1.26 g/cm³
Equilibrium temperature	228.76 K
System distance	21.14 pc

Published measurements

4 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 5 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
556.8354	M_earth	± 17.16	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
565.7374	M_earth	± 25.43	Radial Velocity	NASA Exoplanet Archive	Stassun et al. 2017	2017
533.93	M_earth	± 22.25	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2007	2007
533.9544	M_earth	± 47.67	Radial Velocity	NASA Exoplanet Archive	Butler et al. 2006	2006
476.7	M_earth		Radial Velocity	NASA Exoplanet Archive	Cochran et al. 1997	1997

Orbital period 5 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
799.45	d	± 0.15	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
798.5	d	± 1	Radial Velocity	NASA Exoplanet Archive	Stassun et al. 2017	2017
799.5	d	± 0.6	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2007	2007
798.5	d	± 1	Radial Velocity	NASA Exoplanet Archive	Butler et al. 2006	2006
800.8	d	± 11.7	Radial Velocity	NASA Exoplanet Archive	Cochran et al. 1997	1997

Semi-major axis 5 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
1.676	au	± 0.025	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
1.66	au	± 0.03	Radial Velocity	NASA Exoplanet Archive	Stassun et al. 2017	2017
1.68	au	± 0.03	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2007	2007
1.681	au	± 0.097	Radial Velocity	NASA Exoplanet Archive	Butler et al. 2006	2006
1.6	au		Radial Velocity	NASA Exoplanet Archive	Cochran et al. 1997	1997

Eccentricity 5 values

Value	Uncertainty	Band / method	Source	Reference	Year
0.6832	± 0.0031	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.68	± 0.02	Radial Velocity	NASA Exoplanet Archive	Stassun et al. 2017	2017
0.689	± 0.011	Radial Velocity	NASA Exoplanet Archive	Wittenmyer et al. 2007	2007
0.681	± 0.017	Radial Velocity	NASA Exoplanet Archive	Butler et al. 2006	2006
0.634	± 0.082	Radial Velocity	NASA Exoplanet Archive	Cochran et al. 1997	1997

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
16 Cyg B	Star	0″	—
* 16 Cyg Bb	Planet	3.272″	—
* 16 Cyg B	HighPM*	3.272″	6.2
* 16 Cyg C	HighPM*	38.64″	—
* 16 Cyg A	**	39.91″	5.95
* 16 Cyg	**	40.11″	—
Kepler-678	Star	83.62″	—
Kepler-678 b	Exoplanet	83.78″	15.16
KOI-4512	**	97.25″	—
UCAC4 703-067678	Star	104.5″	13.11
2MASS J19420615+5030220	Star	142.7″	—

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/16-cyg-b-b · Registry entry updated 2026-08-14.