Key parameters at a glance

A radius of 13.00 Earth radii
A mass of 1,142.00 Earth masses
Surface gravity around 6.76 g
An orbital period of 1,000.000 days
Equilibrium temperature 186 K (-87 °C)
Distance from Earth 877.96 light-years
Earth Similarity Index 0.366
Travel time at Voyager 1 speed 15,482,762 years

1 sibling around K2-73

K2-73 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
K2-73 b	Sub-Neptune	2.58	9.20	7.496	968	2016
K2-73 c this	Gas Giant	13.00	1,142.00	1,000.000	186	2025

K2-73 c Planet Profile

Physical Specs

Radius

13.00 R⊕

Radius (Jupiter)

1.160 R♃

Mass

1,142.00 M⊕

Mass (Jupiter)

3.593 M♃

Density

2.86 g/cm³

Surface Gravity

6.76 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.366

HZ Position Outer

Controversial No

Discovery

Year 2025

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#960of 1771

top 54.2%

This planet

13.00R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HIP 14810 b 13.00 R⊕ HD 47186 c 13.00 R⊕ WASP-107 c 13.00 R⊕

Metric	Earth	K2-73 c	Jupiter
Radius (R⊕)	1.00	13.00	11.21
Mass (M⊕)	1.00	1,142.00	317.83
Density (g/cm³)	5.51	2.86	1.33
Surface Gravity (g)	1.00	6.76	2.53
Insolation (S⊕)	1.00	0.29	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	1,142.000 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 38354061

Gaia DR2

Gaia DR2 2616071555020488960

Gaia DR3

Gaia DR3 2616071555020488960

System

K2-73

Percentile among Gas Giant cohort

Radius 13.000 R⊕ · percentile 43 / cohort 1771

Mass 1,142.000 M⊕ · percentile 69 / cohort 1747

Orbital period 1,000.00 d · percentile 77 / cohort 1533

Distance 269.18 pc · percentile 57 / cohort 1759

ESI 0.366 · percentile 75 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

1,000.000 days

Semi-major axis

— AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts about 2.74 Earth years.

Eq. Temperature

186K

(-87 °C)

Insolation (S⊕)

0.29

Earth = 1.00

Earth Similarity (ESI)

0.366

0 = alien, 1 = Earth-identical

Beyond the outer HZ boundary (too cold) — surface water would be frozen.

Discovery Paper

Primary reference

Howard et al. 2025

Instrument

HIRES Spectrometer

Publication

2025-06

Observation locale

Ground

Host System: K2-73

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,867 K — hotter than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.058 R☉

Stellar Mass

1.020 M☉

Metallicity [Fe/H]

0.04

Extended Stellar Properties

Surface gravity (log g)

4.390 dex

Stellar density

1.266 g/cm³

Systemic radial velocity

-38.41 km/s

Rotational v·sin i

2.00 km/s

Activity index (log R'HK)

-4.999

Metallicity ratio

[Fe/H]

Distance

269.18 parsec

Light-years 877.96 ly

V-band magnitude

11.35 mag

Voyager-speed travel 15,482,762 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

3.686 mas

Total Proper Motion

50.201 mas/yr

PM Right Ascension

49.27 mas/yr

PM Declination

9.61 mas/yr

Galactic Cartesian (pc)

x = 0.895 · y = -0.417 · z = -0.157

Equatorial (J2000)

RA 335.02566° · Dec -9.05609°

Galactic ℓ, b

52.521° · -49.989°

Ecliptic λ, β

333.556° · 1.229°

HTM-20 index

374146318