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]

Exoplanet  | 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[3][4] | Extrasolar planetesimal. Likely a remnant iron core. Radius is in the range of 1.2 - 120 km.[3]
WD 1145+017 b | ~0.03[5] | Disintegrating planetesimal, likely one of several orbiting its star. Likely about one-tenth the mass of Ceres and ~200 km in radius.[5]
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.[6][7]
PSR B1257+12 b (Draugr)  | ~0.338 | Least massive known exoplanet, at 0.02 Earth masses. Radius estimated 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-444b | 0.403+0.016
−0.014 | [11]
Ganymede | 0.413  | Shown for comparison
Kepler-102b | 0.460±0.026 | [7]
Kepler-444c | 0.497+0.021
−0.017 | [11]
Kepler-1971b (KOI-4777.01)  | 0.51±0.03 | [12]
Kepler-1994b | 0.51+0.06
−0.05 | [13]
Kepler-1308b | 0.52+0.06
−0.05 |
Kepler-444d | 0.530+0.022
−0.019 | [11]
Mars | 0.5325  | Shown for comparison
Kepler-62c | 0.54±0.03 |
Kepler-444e | 0.546+0.017
−0.015 | [11]
Gliese 238 b | 0.566±0.014 | [14]
Kepler-102c | 0.567±0.028 | [7]
Kepler-42d | 0.57±0.18 |
Kepler-1583b | 0.60+0.09
−0.05 |
Kepler-1998b | 0.6+0.08
−0.04 | [15]
Kepler-1087b | 0.61+0.17
−0.05 |
K2-89b | 0.615±0.080 |
Kepler-1877b | 0.624  |
K2-137b | 0.64±0.10 |
Kepler-1371c | 0.64+0.07
−0.05 |
Kepler-138b | 0.64±0.02 | [16]
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 | [17]
K2-116b | 0.69±0.04 |
Kepler-141b | 0.69±0.05 |
K2-297b (EPIC 201497682 b)  | 0.692+0.059
−0.048 |
Gliese 367 b (Tahay)  | 0.699±0.024 | Smallest known exoplanet within 10 parsecs.[18]
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,[19] and assuming its existence, a 2023 study found a mass of 8.1±1.7 M🜨, inconsistent with such a small radius.[20]

KOI-6705.01, listed as a potential very small planet in the KOI dataset, was shown to be a false positive in 2016.[21]

### Kepler and TESS candidates

[edit]

Below shows a list of Kepler and TESS candidates below 0.7 R🜨 that have yet to be confirmed.

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

|
|

KOI-4582.01  | 0.35[22] |
KOI-2298.03  | 0.36[22] |
KIC 1718360.01  | 0.366[23] |
KOI-2169.04  | 0.37[22] |
KOI-7174.01  | 0.37[22] |
KOI-8012.01  | 0.42[22] |
KOI-6860.01  | 0.43[22] |
KOI-2059.02  | 0.44[22] |
KOI-304.02  | 0.46[22] |
KOI-7793.01  | 0.46[22] |
KOI-2678.02  | 0.48[22] |
KOI-6631.01  | 0.48[22] |
KOI-2421.02  | 0.48[22] |
KOI-5974.01  | 0.49[22] |
KOI-3444.03  | 0.5[22] |
KOI-2295.01  | 0.52[22] |
KOI-7863.01  | 0.52[22] |
KOI-2612.02  | 0.53[22] |
KOI-4657.01  | 0.54[22] |
KOI-8257.01  | 0.54[22] |
KOI-115.03 (Kepler-105d)  | 0.55+0.08
−0.07 | [24]
KOI-2421.01  | 0.55[22] |
KOI-4097.02  | 0.55[22] |
KOI-7645.01  | 0.55[22] |
KOI-3208.01  | 0.56[22] |
KOI-6763.01  | 0.56[22] |
KOI-2859.03  | 0.57[22] |
KOI-4146.02  | 0.57[22] |
KOI-2859.04  | 0.57[22] |
KOI-7873.01  | 0.57[22] |
TOI-4307.02  | 0.57±0.14[25] |
KOI-2657.01  | 0.58[22] |
KOI-8277.01  | 0.58[22] |
KOI-4296.01  | 0.59[22] |
KOI-3196.01  | 0.59[22] |
KOI-5692.01  | 0.59[22] |
KOI-1964.01  | 0.6[22] |
KOI-4407.01  | 0.6[22] |
KOI-4871.01  | 0.6[22] |
KOI-5211.01  | 0.6[22] |
KOI-7888.01  | 0.6[22] |
KOI-3184.03  | 0.6[22] |
KOI-8183.01  | 0.6[22] |
KOI-3083.02  | 0.61[22] |
KOI-4421.01  | 0.61[22] |
KOI-4716.01  | 0.61[22] |
KOI-3102.01  | 0.61[22] |
KOI-7032.01  | 0.61[22] |
KOI-1843.03  | 0.61+0.12
−0.08 | [26]
KOI-1499.02  | 0.62[22] |
KOI-605.02  | 0.62[22] |
KOI-7676.01  | 0.62[22] |
KOI-4849.01  | 0.62[22] |
KOI-365.02  | 0.62[22] |
KOI-7116.01  | 0.62[22] |
KOI-4421.02  | 0.62[22] |
KOI-7949.01  | 0.62[22] |
KOI-2029.04  | 0.63[22] |
KOI-6889.01  | 0.63[22] |
KOI-2636.02  | 0.63[22] |
KOI-3248.01  | 0.64[22] |
KOI-5213.01  | 0.64[22] |
KOI-6276.01  | 0.64[22] |
KOI-7617.01 | 0.64[22] |
KOI-7903.01  | 0.64[22] |
KOI-7925.01  | 0.64[22] |
KOI-8174.01  | 0.64[22] |
KOI-3083.03  | 0.65[22] |
KOI-4875.01  | 0.65[22] |
KOI-4808.01  | 0.65[22] |
KOI-6568.01  | 0.65[22] |
KOI-1619.01  | 0.66[22] |
KOI-3111.02  | 0.66[22] |
KOI-2859.05  | 0.66[22] |
KOI-3017.01  | 0.67[22] |
KOI-4907.01  | 0.67[22] |
KOI-1616.02  | 0.67[22] |
KOI-6299.01  | 0.67[22] |
KOI-8211.01  | 0.67[22] |
KOI-2593.02  | 0.68[22] |
KOI-4605.01  | 0.68[22] |
KOI-7832.01  | 0.68[22] |
KOI-7483.01  | 0.68[22] |
KOI-2623.02  | 0.68[22] |
KOI-7924.01  | 0.68[22] |
KOI-7628.01  | 0.69[22] |
KOI-4129.01  | 0.69[22] |
KOI-4822.01  | 0.69[22] |
KOI-6600.01  | 0.69[22] |

## See also

[edit]

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

## References

[edit]

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