Registry · exoplanet

55 Cnc f

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: 08h 52m 35.24s
Declination: +28° 19′ 47.3″
Galactic l, b: 196.8, 37.7
Magnitude V: 5.951
Distance: 12.585 pc

Planet

NASA Exoplanet Archive, composite parameters

Host star	55 Cnc · G8 V
Discovery	Radial Velocity, 2007 · Multiple Observatories
Orbital period	260.58 d
Semi-major axis	0.802 au
Eccentricity	0.063
Radius	7.59 R⊕ · 0.677 R♃
Mass	44.812 M⊕ · 0.141 M♃
Density	0.563 g/cm³
Equilibrium temperature	277.07 K
System distance	12.585 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 9 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
48.5	M_earth	± 2.8	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
40.4	M_earth	± 2.9	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
46.87969	M_earth	± 2.988	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
47.8	M_earth	± 2.4	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
44.812	M_earth	± 3.814	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
47.0051	M_earth	± 6.96	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
54.664	M_earth	± 2.543	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
44.812	M_earth	± 12.39	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
45.766	M_earth	± 12.71	Radial Velocity	NASA Exoplanet Archive	Fischer et al. 2008	2008

Orbital period 9 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
260.58	d	± 0.15	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
260.54	d	± 0.27	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
260.98	d	± 0.24	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
259.88	d	± 0.29	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
262	d	± 0.51	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
260.91	d	± 0.36	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
261.2	d	± 0.4	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
260.7	d	± 1.1	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
260	d	± 1.1	Radial Velocity	NASA Exoplanet Archive	Fischer et al. 2008	2008

Semi-major axis 9 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.802	au	± 0.014	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
0.75	au	± 0.015	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
0.792	au	± 0.012	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.7708	au	± 0.0043	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
0.788	au	± 0.001	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
0.7733	au	± 0.001	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
0.77	au	± 0.005	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
0.775	au	± 0.045	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
0.781	au	± 0.007	Radial Velocity	NASA Exoplanet Archive	Fischer et al. 2008	2008

Eccentricity 9 values

Value	Uncertainty	Band / method	Source	Reference	Year
0.063	± 0.048	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
0.103	± 0.073	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
0.142	± 0.06	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.08	± 0.05	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
0.305	± 0.075	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
0.08	± 0.102	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
0.32	± 0.05	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
0	± 0.2	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
0.2	± 0.2	Radial Velocity	NASA Exoplanet Archive	Fischer et al. 2008	2008

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
55 Cnc	Star	0″	—
55 Cnc e	Exoplanet	0″	5.951
55 Cnc d	Exoplanet	0″	5.951
55 Cnc c	Exoplanet	0″	5.951
55 Cnc b	Exoplanet	0″	5.951
* rho01 Cnc f	Planet	8.353″	—
* rho01 Cnc e	Planet	8.353″	—
* rho01 Cnc	HighPM*	8.353″	—
* rho01 Cnc b	Planet	8.353″	—
* rho01 Cnc c	Planet	8.353″	—
* rho01 Cnc d	Planet	8.353″	—

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/55-cnc-f · Registry entry updated 2026-08-14.