Key parameters at a glance

A radius of 2.91 Earth radii
A mass of 8.80 Earth masses
Surface gravity around 1.04 g
An orbital period of 9.554 days
Semi-major axis 0.0680 AU
Equilibrium temperature 406 K (133 °C)
Distance from Earth 46.43 light-years
Earth Similarity Index 0.558
Travel time at Voyager 1 speed 818,809 years
Almost certainly tidally locked to its host star given the close orbit

GJ 480 b Planet Profile

Physical Specs

Radius

2.91 R⊕

Radius (Jupiter)

0.260 R♃

Mass

8.80 M⊕

Mass (Jupiter)

0.028 M♃

Density

1.96 g/cm³

Surface Gravity

1.04 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.558

HZ Position Unknown

Controversial No

Discovery

Year 2020

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#608of 1978

top 30.7%

This planet

2.91R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-1221 b 2.91 R⊕ HD 45184 c 2.91 R⊕ TOI-1117 c 2.91 R⊕

Metric	Earth	GJ 480 b	Jupiter
Radius (R⊕)	1.00	2.91	11.21
Mass (M⊕)	1.00	8.80	317.83
Density (g/cm³)	5.51	1.96	1.33
Surface Gravity (g)	1.00	1.04	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	8.800 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 61706

TIC

TIC 399119319

Gaia DR2

Gaia DR2 3928391218812375808

Gaia DR3

Gaia DR3 3928391218812375808

System

GJ 480

Percentile among Sub-Neptune cohort

Radius 2.910 R⊕ · percentile 69 / cohort 1978

Mass 8.800 M⊕ · percentile 63 / cohort 1978

Orbital period 9.55 d · percentile 32 / cohort 1946

Distance 14.24 pc · percentile 2 / cohort 1975

ESI 0.558 · percentile 77 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

9.554 days

Semi-major axis

0.0680 AU

Eccentricity

0.000

Inclination

— °

Year Length

A year here lasts approximately 9.55 Earth days (2.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0680 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

4.500 m/s

Transit mid-time (BJD)

2,458,446.0000

Long. of periastron (ω)

151.00°

Angular separation (arcsec)

4.78000

Eq. Temperature

406K

(133 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.558

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Feng et al. 2020

Instrument

Multiple Instruments

Publication

2020-10

Observation locale

Ground

Discovery cohort

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

GJ 3473 c · Sub-Neptune HIP 38594 b · Sub-Neptune HD 216520 c · Sub-Neptune HD 216520 b · Sub-Neptune HIP 107772 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 480

Spectral Class

M-type red dwarf

Effective Temperature

3,509 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.449 R☉

Stellar Mass

0.450 M☉

Metallicity [Fe/H]

0.26

Extended Stellar Properties

Surface gravity (log g)

4.880 dex

Stellar density

6.740 g/cm³

Rotation period

50.30 days

Metallicity ratio

[m/H]

Distance

14.24 parsec

Light-years 46.43 ly

V-band magnitude

11.49 mag

Voyager-speed travel 818,809 yr

Multi-band Host Photometry — 13 bands

Astrometric Data

Parallax

70.216 mas

Total Proper Motion

1,182.652 mas/yr

PM Right Ascension

-1,155.70 mas/yr

PM Declination

-251.04 mas/yr

Galactic Cartesian (pc)

x = -0.965 · y = -0.165 · z = 0.203

Equatorial (J2000)

RA 189.71342° · Dec 11.69507°

Galactic ℓ, b

291.486° · 74.287°

Ecliptic λ, β

184.200° · 14.578°

HTM-20 index

669768942