Key parameters at a glance

A radius of 2.28 Earth radii
A mass of 5.82 Earth masses
Surface gravity around 1.12 g
An orbital period of 647.600 days
Semi-major axis 1.3541 AU
Distance from Earth 19.58 light-years
Earth Similarity Index 0.738
Travel time at Voyager 1 speed 345,266 years

2 siblings around HD 20794

HD 20794 f shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HD 20794 b	Super-Earth	1.45	2.70	18.314	660	2011
HD 20794 d	Sub-Neptune	2.04	4.80	89.680	388	2011
HD 20794 f this	Sub-Neptune	2.28	5.82	647.600	—	2025

HD 20794 f Planet Profile

Physical Specs

Radius

2.28 R⊕

Radius (Jupiter)

0.203 R♃

Mass

5.82 M⊕

Mass (Jupiter)

0.018 M♃

Density

2.70 g/cm³

Surface Gravity

1.12 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.738

HZ Position Unknown

Controversial No

Discovery

Year 2025

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#1536of 1978

top 77.6%

This planet

2.28R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

GJ 806 c 2.28 R⊕ Kepler-1020 b 2.28 R⊕ DMPP-6 b 2.28 R⊕

Metric	Earth	HD 20794 f	Jupiter
Radius (R⊕)	1.00	2.28	11.21
Mass (M⊕)	1.00	5.82	317.83
Density (g/cm³)	5.51	2.70	1.33
Surface Gravity (g)	1.00	1.12	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	5.820 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 20794

HIP

HIP 15510

TIC

TIC 301051051

Gaia DR2

Gaia DR2 4847957293277762560

Gaia DR3

Gaia DR3 4847957293278177024

System

HD 20794

Percentile among Sub-Neptune cohort

Radius 2.280 R⊕ · percentile 22 / cohort 1978

Mass 5.820 M⊕ · percentile 22 / cohort 1978

Orbital period 647.60 d · percentile 100 / cohort 1946

Distance 6.00 pc · percentile 0 / cohort 1975

ESI 0.738 · percentile 96 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

647.600 days

Semi-major axis

1.3541 AU

Eccentricity

0.450

Inclination

— °

Year Length

A year here lasts about 1.77 Earth years on a highly eccentric trajectory at a mean orbital distance of 1.3541 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.738

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Nari et al. 2025

Instrument

Multiple Instruments

Publication

2025-01

Observation locale

Ground

Discovery cohort

Planets confirmed in 2025 at Multiple Observatories (12 shown).

Gl 725 A b · Super-Earth GJ 3998 d · Sub-Neptune GJ 251 c · Super-Earth HD 86728 b · Sub-Neptune TOI-2015 c · Sub-Neptune Kepler-139 f · Neptune-like HD 73344 d · Gas Giant TOI-1472 c · Sub-Neptune TOI-6695 c · Gas Giant AT2021ueyL b · Gas Giant HIP 111909 b · Gas Giant TOI-6041 c · Gas Giant

Host System: HD 20794

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,368 K — cooler than the Sun (5,778 K)

Estimated Age

5.76 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.930 R☉

Stellar Mass

0.790 M☉

Metallicity [Fe/H]

-0.42

Extended Stellar Properties

Surface gravity (log g)

4.390 dex

Stellar density

1.704 g/cm³

Systemic radial velocity

87.88 km/s

Rotational v·sin i

3.00 km/s

Activity index (log R'HK)

-4.980

Metallicity ratio

[Fe/H]

Distance

6.00 parsec

Light-years 19.58 ly

V-band magnitude

4.26 mag

Voyager-speed travel 345,266 yr

Multi-band Host Photometry — 8 bands

Astrometric Data

Parallax

166.561 mas

Total Proper Motion

3,120.505 mas/yr

PM Right Ascension

3,033.73 mas/yr

PM Declination

730.78 mas/yr

Galactic Cartesian (pc)

x = 0.470 · y = 0.560 · z = -0.683

Equatorial (J2000)

RA 49.99977° · Dec -43.06665°

Galactic ℓ, b

250.734° · -56.065°

Ecliptic λ, β

27.244° · -58.115°

HTM-20 index

-869587511