Registry · exoplanet

55 Cnc e

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, 2004 · McDonald Observatory
Orbital period	0.736547 d
Semi-major axis	0.01544 au
Eccentricity	0.05
Radius	1.875 R⊕ · 0.1673 R♃
Mass	7.99 M⊕ · 0.02514 M♃
Density	6.66 g/cm³
Equilibrium temperature	1,958 K
System distance	12.585 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 14 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
9.35	M_earth	± 0.44	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
7.95	M_earth	± 0.45	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
9.375938	M_earth	± 0.445	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
7.74	M_earth	± 0.37	Radial Velocity	NASA Exoplanet Archive	Dai et al. 2019	2019
7.99	M_earth	± 0.32	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
8.59	M_earth	± 0.43	Radial Velocity	NASA Exoplanet Archive	Crida et al. 2018	2018
8.08	M_earth	± 0.31	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2016	2016
8.13928	M_earth	± 0.232	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
8.09479	M_earth	± 0.2606	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
8.37	M_earth	± 0.38	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
7.81	M_earth	± 0.58	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2011	2011
8.63	M_earth	± 0.35	Radial Velocity	NASA Exoplanet Archive	Winn et al. 2011	2011

Show the remaining 2

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
7.4687	M_earth	± 1.557	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
14.30235	M_earth	± 3.178	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2004	2004

Radius 10 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
1.856	R_earth	± 0.024	Radial Velocity	NASA Exoplanet Archive	Zhao et al. 2023	2023
1.897	R_earth	± 0.044	Radial Velocity	NASA Exoplanet Archive	Dai et al. 2019	2019
1.875	R_earth	± 0.029	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
1.947	R_earth	± 0.038	Radial Velocity	NASA Exoplanet Archive	Crida et al. 2018	2018
1.92	R_earth	± 0.08	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2016	2016
1.91	R_earth	± 0.08	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2016	2016
2.173	R_earth	± 0.097	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
2.08	R_earth	± 0.16	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2011	2011
2	R_earth	± 0.14	Radial Velocity	NASA Exoplanet Archive	Winn et al. 2011	2011
2.023112	R_earth	± 0.1826	Radial Velocity	NASA Exoplanet Archive	ExoFOP	2004

Orbital period 19 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.736546	d	± 1.00e-06	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
0.736547	d	± 1.70e-06	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
0.7365462	d	± 1.50e-07	Radial Velocity	NASA Exoplanet Archive	Kokori et al. 2023	2023
0.736543	d	± 1.40e-06	Radial Velocity	NASA Exoplanet Archive	Zhao et al. 2023	2023
0.7365445	d	± 1.40e-06	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.736546	d	± 1.60e-07	Radial Velocity	NASA Exoplanet Archive	Zhang et al. 2021	2021
0.737	d		Radial Velocity	NASA Exoplanet Archive	Dai et al. 2019	2019
0.7365474	d	± 1.30e-06	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
0.7365474	d	± 1.30e-06	Radial Velocity	NASA Exoplanet Archive	Crida et al. 2018	2018
0.736539	d	± 7.00e-06	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2016	2016
0.7365515	d	± 1.50e-06	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
0.7365478	d	± 1.60e-06	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014

Show the remaining 7

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.7365417	d	± 2.50e-06	Radial Velocity	NASA Exoplanet Archive	Bourrier & Hébrard 2014	2014
0.736546	d	± 3.00e-06	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
0.7365437	d	± 5.20e-06	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2011	2011
0.73654	d	± 3.00e-06	Radial Velocity	NASA Exoplanet Archive	Winn et al. 2011	2011
2.79674	d	± 0.0001	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
0.7365463	d	± 8.52e-07	Radial Velocity	NASA Exoplanet Archive	ExoFOP	2004
2.808	d	± 0.002	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2004	2004

Semi-major axis 12 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
0.016	au	± 0.0003	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
0.015	au	± 0.0003	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
0.01583	au	± 0.00024	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.01544	au	± 5.00e-05	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
0.01544	au	± 9.00e-05	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2016	2016
0.01569091	au	± 2.10e-08	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
0.015439	au	± 1.50e-05	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
0.01583	au	± 0.0002	Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
0.01544	au	± 9.00e-05	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2011	2011
0.01583	au	± 0.0002	Radial Velocity	NASA Exoplanet Archive	Winn et al. 2011	2011
0.0377	au	± 0.0022	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
0.038	au	± 0.001	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2004	2004

Eccentricity 10 values

Value	Uncertainty	Band / method	Source	Reference	Year
0.01	± 0.02	Radial Velocity	NASA Exoplanet Archive	Moutou et al. 2026	2026
0.032	± 0.034	Radial Velocity	NASA Exoplanet Archive	Harada et al. 2025	2025
0.036	± 0.034	Radial Velocity	NASA Exoplanet Archive	Rosenthal et al. 2021	2021
0.05	± 0.03	Radial Velocity	NASA Exoplanet Archive	Bourrier et al. 2018	2018
0.04	± 0.027	Radial Velocity	NASA Exoplanet Archive	Baluev 2015	2015
0.028	± 0.022	Radial Velocity	NASA Exoplanet Archive	Nelson et al. 2014	2014
0		Radial Velocity	NASA Exoplanet Archive	Endl et al. 2012	2012
0.061	± 0.065	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2011	2011
0.264	± 0.06	Radial Velocity	NASA Exoplanet Archive	Wright et al. 2009	2009
0.174	± 0.127	Radial Velocity	NASA Exoplanet Archive	McArthur et al. 2004	2004

Equilibrium temperature 2 values

Value	Unit	Uncertainty	Band / method	Source	Reference	Year
1,958	K	± 15	Radial Velocity	NASA Exoplanet Archive	Demory et al. 2011	2011
1,831.27	K		Radial Velocity	NASA Exoplanet Archive	ExoFOP	2004

In the same field

within 9 arcmin · wider search

Object	Type	Separation	V
55 Cnc	Star	0″	—
55 Cnc f	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-e · Registry entry updated 2026-08-14.