Key parameters at a glance
- A radius of 2.18 Earth radii
- A mass of 5.40 Earth masses
- Surface gravity around 1.14 g
- An orbital period of 264.284 days
- Distance from Earth 2,556.51 light-years
- Earth Similarity Index 0.754
- Travel time at Voyager 1 speed 45,084,084 years
Context from the literature
Kepler-51 is a Sun-like star that is about 500 million years old. It is orbited by four planets—Kepler-51b, c, d and e—first three of which are super-puffs and have the lowest known densities of any known exoplanet. The transiting planets in the system are similar in radius to gas giants like Jupiter, but have unusually small masses for their size, only a few times greater than Earth's.
Excerpted from Wikipedia · full article
3 siblings around Kepler-51
Kepler-51 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-51 b | Neptune-like | 7.10 | 2.10 | 45.154 | 543 | 2012 |
| Kepler-51 c | Neptune-like | 9.00 | 4.00 | 85.312 | 439 | 2012 |
| Kepler-51 d | Neptune-like | 9.70 | 7.60 | 130.194 | 381 | 2014 |
| Kepler-51 e this | Sub-Neptune | 2.18 | 5.40 | 264.284 | — | 2024 |
Kepler-51 e Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1703of 1978
top 86.0%
This planet
2.18R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-51 e | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.18 | 11.21 |
| Mass (M⊕) | 1.00 | 5.40 | 317.83 |
| Density (g/cm³) | 5.51 | 2.86 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.14 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 5.400 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 27846348
Gaia DR2
Gaia DR2 2135275362382289280
Gaia DR3
Gaia DR3 2135275362382289280
System
Kepler-51
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 264.28 Earth days (72.4% of a terrestrial year) on a nearly circular orbit.
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.754
0 = alien, 1 = Earth-identical
Discovery Paper
Primary reference
Masuda et al. 2024Instrument
Multiple Instruments
Publication
2024-10
Observation locale
Ground
Discovery cohort
Planets confirmed in 2024 at Multiple Observatories (12 shown).
Host System: Kepler-51
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,674 K — cooler than the Sun (5,778 K)
Estimated Age
0.70 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.870 R☉
Stellar Mass
0.960 M☉
Metallicity [Fe/H]
0.05
Extended Stellar Properties
Surface gravity (log g)
4.700 dex
Stellar density
2.087 g/cm³
Rotation period
8.22 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.247 mas
Total Proper Motion
7.458 mas/yr
PM Right Ascension
0.01 mas/yr
PM Declination
-7.46 mas/yr
Galactic Cartesian (pc)
x = 0.287 · y = -0.576 · z = 0.765
Equatorial (J2000)
RA 296.47976° · Dec 49.93765°
Galactic ℓ, b
83.113° · 12.362°
Ecliptic λ, β
322.007° · 68.646°
HTM-20 index
-464884401
Similar Worlds
Kepler-1016 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.18 R⊕ · 4,575.4 ly
HD 158259 d
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.18 R⊕ · 88.2 ly
Kepler-1444 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.18 R⊕ · 1,042.6 ly
Kepler-790 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.18 R⊕ · 2,293.4 ly
Kepler-594 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.18 R⊕ · 2,508.8 ly
Kepler-1742 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.18 R⊕ · 2,183.9 ly