List of smallest exoplanets

A size comparison of the planets in the Kepler-37 system and objects in the Solar System

Below is a list of the smallest exoplanets so far discovered, in terms of physical size, ordered by radius.

## List

[edit]

This is a dynamic list and may never be able to satisfy particular standards for completeness. You can help by adding missing items with reliable sources.

The sizes are listed in units of Earth radii (R🜨). All planets listed are smaller than Earth and Venus, up to 0.7 Earth radii. The NASA Exoplanet Archive is used as the main data source.[1][2] Radii listed in italics are estimates.

Exoplanet  | Radius (R🜨)  | Notes and references

|
|

SDSS J0845+2257 b | 0.01-0.013  | Planetesimal, enhanced in iron and silicates. [3]
WD 1145+017 b | ~0.03[4] | Disintegrating planetesimal, likely one of several orbiting its star. Likely about one-tenth the mass of Ceres and ~200 km in radius.[4]
Ceres | 0.0742  | Shown for comparison
Pluto | 0.1863  | Shown for comparison
Moon | 0.2725  | Shown for comparison
Kepler-37b | 0.3098+0.0059
−0.0076 | Smallest known exoplanet.[5][6]
BD+05 4868 Ab | ~0.314 | Disintegrating planet, radius is just an estimate.[7]
PSR B1257+12 b (Draugr)  | ~0.338 | Least massive known exoplanet, at 0.02 Earth masses. Radius predicted from mass-radius relationship.[8]
Kepler-1520b | ≲0.36 | Disintegrating planets with poorly known radii, all thought to be smaller than Mercury.[9][10]
KOI-2700b
K2-22b
Mercury | 0.3826  | Shown for comparison
Kepler-879c | 0.4±0.1 | [11]
Kepler-444b | 0.403+0.016
−0.014 | [12]
Ganymede | 0.413  | Shown for comparison
Kepler-158d | 0.43±0.05 | [11]
Kepler-102b | 0.460±0.026 | [6]
Kepler-444c | 0.497+0.021
−0.017 | [12]
Kepler-1971b (KOI-4777.01)  | 0.51±0.03 | [13]
Kepler-1489c | 0.51±0.08 | [11]
Kepler-1994b | 0.51+0.06
−0.05 | [14]
Kepler-1308b | 0.52+0.06
−0.05 |
Kepler-444d | 0.530+0.022
−0.019 | [12]
Mars | 0.5325  | Shown for comparison
Kepler-62c | 0.54±0.03 |
Kepler-444e | 0.546+0.017
−0.015 | [12]
Gliese 238 b | 0.566±0.014 | [15]
Kepler-102c | 0.567±0.028 | [6]
Kepler-42d | 0.57±0.18 |
Kepler-1583b | 0.60+0.09
−0.05 |
Kepler-1998b | 0.6+0.08
−0.04 | [16]
Kepler-963c | 0.6±0.2 | [11]
Kepler-974c (KOI-1843.03)  | 0.61+0.12
−0.08 | Candidate.[17] As of 2025[update], the Exoplanet Archive lists it as confirmed.[2]
Kepler-1087b | 0.61+0.17
−0.05 |
K2-89b | 0.615±0.080 |
Kepler-1877b | 0.624  |
Barnard's Star e | ~0.637 | Radius predicted from mass-radius relationship.[2] Least massive exoplanet detected by radial velocity and possibly smallest known within 10 parsecs.[18]
K2-137b | 0.64±0.10[19] | The discovery paper finds a larger radius of 0.89±0.09 R🜨[20]
Kepler-1371c | 0.64+0.07
−0.05 |
Kepler-138b | 0.64±0.02 | [21]
Kepler-1130d | 0.645  |
Kepler-1351b | 0.65+0.05
−0.04 |
Kepler-1542c | 0.65+0.09
−0.06 |
Kepler-271d | 0.66±0.05 |
Kepler-431c | 0.668  |
Kepler-1558b | 0.68+0.06
−0.04 |
LHS 1678 b | 0.685+0.037
−0.035 | [22]
K2-116b | 0.69±0.04 |
Kepler-141b | 0.69±0.05 |
K2-297b (EPIC 201497682 b)  | 0.692+0.059
−0.048 |
Barnard's Star d | ~0.694 | Radius predicted from mass-radius relationship.[2][18]
Gliese 367 b (Tahay)  | 0.699±0.024 | Smallest exoplanet within 10 parsecs with a measured radius.[23]
Kepler-2003b (KOI-4978.02)  | 0.7±0.1 | [11]
Kepler-378c | 0.70±0.05 |

### Excluded objects

[edit]

Kepler-37e is listed with a radius of 0.37±0.18 R🜨 in the Exoplanet Archive based on KOI data, but the existence of this planet is doubtful,[24] and assuming its existence, a 2023 study found a mass of 8.1±1.7 M🜨, inconsistent with such a small radius.[25]

KOI-6705.01, listed as a potential very small planet in the KOI dataset, was shown to be a false positive in 2016.[26]

## Candidate planets

[edit]

Below shows a list candidate planets below 0.7 R🜨. These planets have yet to be confirmed.

Kepler object of interest  | Radius (R🜨)  | Notes and references

|
|

SDSS J1228+1040 b
(SDSS J122859.92+104033.0 b, WD 1226+110 b)  | 0.010+0.0504
−0.0085[27][28] | Extrasolar planetesimal. Likely a remnant iron core. Radius is in the range of 1.2 – 120 km.[27] Has been disputed in a 2023 publication.[29]
KOI-4582.01  | 0.35[30] |
KOI-2298.03  | 0.36[30] |
KIC 1718360.01  | 0.366[31] |
KOI-2169.04  | 0.37[30] |
KOI-7174.01  | 0.37[30] |
KOI-8012.01  | 0.42[30] |
KOI-6860.01  | 0.43[30] |
KOI-2059.02  | 0.44[30] |
KOI-304.02  | 0.46[30] |
KOI-7793.01  | 0.46[30] |
KOI-2678.02  | 0.48[30] |
KOI-6631.01  | 0.48[30] |
KOI-2421.02  | 0.48[30] |
KOI-5974.01  | 0.49[30] |
KOI-3444.03  | 0.5[30] |
KOI-2295.01  | 0.52[30] |
KOI-7863.01  | 0.52[30] |
KOI-2612.02  | 0.53[30] |
KOI-4657.01  | 0.54[30] |
KOI-8257.01  | 0.54[30] |
KOI-115.03 (Kepler-105d)  | 0.55+0.08
−0.07 | [32]
KOI-2421.01  | 0.55[30] |
KOI-4097.02  | 0.55[30] |
KOI-7645.01  | 0.55[30] |
KOI-3208.01  | 0.56[30] |
KOI-6763.01  | 0.56[30] |
KOI-2859.03  | 0.57[30] |
KOI-4146.02  | 0.57[30] |
KOI-2859.04  | 0.57[30] |
KOI-7873.01  | 0.57[30] |
TOI-4307.02  | 0.57±0.14[33] |
KOI-2657.01  | 0.58[30] |
KOI-8277.01  | 0.58[30] |
KOI-4296.01  | 0.59[30] |
KOI-3196.01  | 0.59[30] |
KOI-5692.01  | 0.59[30] |
KOI-1964.01  | 0.6[30] |
KOI-4407.01  | 0.6[30] |
KOI-4871.01  | 0.6[30] |
KOI-5211.01  | 0.6[30] |
KOI-7888.01  | 0.6[30] |
KOI-3184.03  | 0.6[30] |
KOI-8183.01  | 0.6[30] |
KOI-3083.02  | 0.61[30] |
KOI-4421.01  | 0.61[30] |
KOI-4716.01  | 0.61[30] |
KOI-3102.01  | 0.61[30] |
KOI-7032.01  | 0.61[30] |
KOI-1499.02  | 0.62[30] |
KOI-605.02  | 0.62[30] |
KOI-7676.01  | 0.62[30] |
KOI-4849.01  | 0.62[30] |
KOI-365.02  | 0.62[30] |
KOI-7116.01  | 0.62[30] |
KOI-4421.02  | 0.62[30] |
KOI-7949.01  | 0.62[30] |
KOI-2029.04  | 0.63[30] |
KOI-6889.01  | 0.63[30] |
KOI-2636.02  | 0.63[30] |
KOI-3248.01  | 0.64[30] |
KOI-5213.01  | 0.64[30] |
KOI-6276.01  | 0.64[30] |
KOI-7617.01 | 0.64[30] |
KOI-7903.01  | 0.64[30] |
KOI-7925.01  | 0.64[30] |
KOI-8174.01  | 0.64[30] |
KOI-3083.03  | 0.65[30] |
KOI-4875.01  | 0.65[30] |
KOI-4808.01  | 0.65[30] |
KOI-6568.01  | 0.65[30] |
KOI-1619.01  | 0.66[30] |
KOI-3111.02  | 0.66[30] |
KOI-2859.05  | 0.66[30] |
KOI-3017.01  | 0.67[30] |
KOI-4907.01  | 0.67[30] |
KOI-1616.02  | 0.67[30] |
KOI-6299.01  | 0.67[30] |
KOI-8211.01  | 0.67[30] |
KOI-2593.02  | 0.68[30] |
KOI-4605.01  | 0.68[30] |
KOI-7832.01  | 0.68[30] |
KOI-7483.01  | 0.68[30] |
KOI-2623.02  | 0.68[30] |
KOI-7924.01  | 0.68[30] |
KOI-7628.01  | 0.69[30] |
KOI-4129.01  | 0.69[30] |
KOI-4822.01  | 0.69[30] |
KOI-6600.01  | 0.69[30] |

## See also

[edit]

* List of largest exoplanets
* List of exoplanet extremes
* Lists of exoplanets

## References

[edit]

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