Key parameters at a glance

A radius of 2.63 Earth radii
A mass of 7.41 Earth masses
Surface gravity around 1.07 g
An orbital period of 15.509 days
Semi-major axis 0.0876 AU
Equilibrium temperature 329 K (56 °C)
Distance from Earth 89.25 light-years
Earth Similarity Index 0.685
Travel time at Voyager 1 speed 1,573,935 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around GJ 3473

GJ 3473 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
GJ 3473 b	Super-Earth	1.26	1.86	1.198	773	2020
GJ 3473 c this	Sub-Neptune	2.63	7.41	15.509	329	2020

GJ 3473 c Planet Profile

Physical Specs

Radius

2.63 R⊕

Radius (Jupiter)

0.235 R♃

Mass

7.41 M⊕

Mass (Jupiter)

0.023 M♃

Density

2.24 g/cm³

Surface Gravity

1.07 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.685

HZ Position Inner

Controversial No

Discovery

Year 2020

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#969of 1978

top 48.9%

This planet

2.63R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-945 b 2.63 R⊕ Kepler-319 c 2.63 R⊕ Kepler-1241 b 2.63 R⊕

Metric	Earth	GJ 3473 c	Jupiter
Radius (R⊕)	1.00	2.63	11.21
Mass (M⊕)	1.00	7.41	317.83
Density (g/cm³)	5.51	2.24	1.33
Surface Gravity (g)	1.00	1.07	2.53
Insolation (S⊕)	1.00	1.95	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	7.410 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 452866790

Gaia DR2

Gaia DR2 3094290054327367168

Gaia DR3

Gaia DR3 3094290054327367168

System

GJ 3473

Percentile among Sub-Neptune cohort

Radius 2.630 R⊕ · percentile 50 / cohort 1978

Mass 7.410 M⊕ · percentile 46 / cohort 1978

Orbital period 15.51 d · percentile 52 / cohort 1946

Distance 27.36 pc · percentile 7 / cohort 1975

ESI 0.685 · percentile 91 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

15.509 days

Semi-major axis

0.0876 AU

Eccentricity

0.000

Inclination

— °

Year Length

A year here lasts approximately 15.51 Earth days (4.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0876 AU.

Eq. Temperature

329K

(56 °C)

Insolation (S⊕)

1.95

Earth = 1.00

Earth Similarity (ESI)

0.685

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Kemmer et al. 2020

Instrument

Multiple Instruments

Publication

2020-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2020 at Multiple Observatories (12 shown).

HIP 38594 b · Sub-Neptune HD 216520 c · Sub-Neptune HD 216520 b · Sub-Neptune HIP 107772 b · Sub-Neptune GJ 480 b · Sub-Neptune HIP 4845 b · Sub-Neptune HD 190007 b · Neptune-like GJ 687 c · Neptune-like GJ 2056 b · Neptune-like HD 238090 b · Sub-Neptune HIP 48714 b · Neptune-like HIP 38594 c · Neptune-like

Host System: GJ 3473

Spectral Class

M-type red dwarf

Effective Temperature

3,347 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.364 R☉

Stellar Mass

0.360 M☉

Metallicity [Fe/H]

0.11

Extended Stellar Properties

Surface gravity (log g)

4.810 dex

Stellar density

10.930 g/cm³

Systemic radial velocity

-1.10 km/s

Rotational v·sin i

2.00 km/s

Rotation period

168.30 days

Metallicity ratio

[Fe/H]

Distance

27.36 parsec

Light-years 89.25 ly

V-band magnitude

13.74 mag

Voyager-speed travel 1,573,935 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

36.515 mas

Total Proper Motion

554.722 mas/yr

PM Right Ascension

-403.17 mas/yr

PM Declination

-381.02 mas/yr

Galactic Cartesian (pc)

x = -0.508 · y = 0.859 · z = 0.058

Equatorial (J2000)

RA 120.59361° · Dec 3.33716°

Galactic ℓ, b

218.151° · 17.288°

Ecliptic λ, β

122.044° · -16.763°

HTM-20 index

1840367210