Confirmed Exoplanet Discovered 2025

Kepler-289 e

A sub-neptune orbiting the g-type yellow (sun-like) Kepler-289, located approximately 2,297.6 light-years from Earth.

Key parameters at a glance

  • A radius of 2.94 Earth radii
  • A mass of 17.40 Earth masses
  • Surface gravity around 2.01 g
  • An orbital period of 330.072 days
  • Semi-major axis 0.9342 AU
  • Equilibrium temperature 286 K (13 °C)
  • Distance from Earth 2,297.57 light-years
  • Earth Similarity Index 0.745
  • Travel time at Voyager 1 speed 40,517,588 years

Context from the literature

Kepler-289 (PH3) is a rotating variable star slightly more massive than the Sun, with a spectral type of G2, 2370 light-years away from Earth in the constellation of Cygnus. It hosts a system of multiple exoplanets.

Excerpted from Wikipedia · full article

3 siblings around Kepler-289

Kepler-289 e shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
Kepler-289 b Sub-Neptune 2.49 3.70 34.538 607 2014
Kepler-289 d Sub-Neptune 3.03 5.33 66.028 — 2014
Kepler-289 c Gas Giant 11.23 157.18 125.872 394 2014
Kepler-289 e this Sub-Neptune 2.94 17.40 330.072 286 2025

Kepler-289 e Planet Profile

Physical Specs

Radius
2.94 R⊕
Radius (Jupiter)
0.262 R♃
Mass
17.40 M⊕
Mass (Jupiter)
0.055 M♃
Density
2.92 g/cm³
Surface Gravity
2.01 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.745
HZ Position Inner
Controversial No

Discovery

Year 2025
Method Transit
Facility Kepler
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#570of 1978

top 28.8%

This planet

2.94R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-210 b 2.94 R⊕ Kepler-67 b 2.94 R⊕ Kepler-58 d 2.94 R⊕
Metric Earth Kepler-289 e Jupiter
Radius (R⊕)1.002.9411.21
Mass (M⊕)1.0017.40317.83
Density (g/cm³)5.512.921.33
Surface Gravity (g)1.002.012.53
Insolation (S⊕)1.001.580.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 17.400 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 273234825

Gaia DR2

Gaia DR2 2078515170549178880

Gaia DR3

Gaia DR3 2078515170549178880

System

Kepler-289

Percentile among Sub-Neptune cohort

Radius 2.940 R⊕ · percentile 71 / cohort 1978
Mass 17.400 M⊕ · percentile 94 / cohort 1978
Orbital period 330.07 d · percentile 99 / cohort 1946
Distance 704.44 pc · percentile 60 / cohort 1975
ESI 0.745 · percentile 96 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
330.072 days
Semi-major axis
0.9342 AU
Eccentricity
0.000
Inclination
89.91 °

Year Length

A year here lasts approximately 330.07 Earth days (90.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.9342 AU.

Transit Fingerprint

Depth

0.062 %

Duration

4.295 h

Impact parameter b

0.680

Rp / R★

0.024100

Transit midpoint (BJD)

2,455,173.9870

Photometric dip

Transit produces a flux drop of 617 ppm lasting ≈ 4.30 h.

Extended Orbital Architecture

Planet / star radius ratio

0.024100

Semi-major axis / stellar radius

449.000

Impact parameter (b)

0.680

Transit mid-time (BJD)

2,455,173.9870

Angular separation (arcsec)

1.33000

Eq. Temperature

286K

(13 °C)

Insolation (S⊕)

1.58

Earth = 1.00

Earth Similarity (ESI)

0.745

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure.

Discovery Paper

Primary reference

Ofir et al. 2025

Instrument

Kepler CCD Array

Publication

2025-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2025 at Kepler (4 shown).

Kepler-725 c · Sub-Neptune Kepler-279 e · Neptune-like KOI-134 c · Neptune-like KOI-134 b · Gas Giant

Host System: Kepler-289

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,990 K — hotter than the Sun (5,778 K)

Estimated Age

0.65 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.985 R☉

Stellar Mass

1.061 M☉

Metallicity [Fe/H]

-0.01

Extended Stellar Properties

Surface gravity (log g)

4.470 dex

Stellar density

1.910 g/cm³

Metallicity ratio

[M/H]

Distance
704.44 parsec
Light-years 2,297.57 ly
V-band magnitude
14.14 mag
Voyager-speed travel 40,517,588 yr

Multi-band Host Photometry — 16 bands

8.914.714.73B14.14V13.96Gaia13.96Kepler13.51TESS14.40Sloan g13.92Sloan r13.76Sloan i13.69Sloan z12.86J12.60H12.51K12.47W112.54W212.88W38.91W4

Astrometric Data

Parallax

1.391 mas

Total Proper Motion

4.785 mas/yr

PM Right Ascension

4.78 mas/yr

PM Declination

-0.24 mas/yr

Galactic Cartesian (pc)

x = 0.338 · y = -0.650 · z = 0.681

Equatorial (J2000)

RA 297.46534° · Dec 42.88285°

Galactic ℓ, b

77.147° · 8.386°

Ecliptic λ, β

316.043° · 62.002°

HTM-20 index

1432308909

Wikipedia →

Similar Worlds

Kepler-1495 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 2.94 R⊕ · 4,421.2 ly

Kepler-1202 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 2.94 R⊕ · 3,833.6 ly

Kepler-139 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 2.94 R⊕ · 1,275.4 ly

Kepler-1041 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 2.94 R⊕ · 4,846.1 ly

Kepler-67 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 2.94 R⊕ · 3,689.4 ly

Kepler-1914 b

Sub-Neptune · G-type yellow (Sun-like)

Radius 2.94 R⊕ · 5,288.8 ly

Explore Related Categories

Sub-Neptune Planets Transit Discoveries Kepler Mission G-type yellow (Sun-like) Hosts