List of smallest exoplanets
Below is a list of the smallest exoplanets so far discovered, in terms of physical size, ordered by radius.
List
[edit]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 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] |
| PSR B1257+12 b (Draugr) | ~0.338 | Least massive known exoplanet, at 0.02 Earth masses. Radius estimated from mass-radius relationship.[7] |
| Kepler-1520b | ≲0.36 | Disintegrating planets with poorly known radii, all thought to be smaller than Mercury.[8][9] |
| KOI-2700b | ||
| K2-22b | ||
| Mercury | 0.3826 | Shown for comparison |
| Kepler-879c | 0.4±0.1 | [10] |
| Kepler-444b | 0.403+0.016 −0.014 |
[11] |
| Ganymede | 0.413 | Shown for comparison |
| Kepler-158d | 0.43±0.05 | [10] |
| Kepler-102b | 0.460±0.026 | [6] |
| Kepler-444c | 0.497+0.021 −0.017 |
[11] |
| Kepler-1971b (KOI-4777.01) | 0.51±0.03 | [12] |
| Kepler-1489c | 0.51±0.08 | [10] |
| 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 | [6] |
| Kepler-42d | 0.57±0.18 | |
| Kepler-1583b | 0.60+0.09 −0.05 |
|
| Kepler-1998b | 0.6+0.08 −0.04 |
[15] |
| Kepler-963c | 0.6±0.2 | [10] |
| Kepler-1087b | 0.61+0.17 −0.05 |
|
| K2-89b | 0.615±0.080 | |
| Kepler-1877b | 0.624 | |
| K2-137b | 0.64±0.10[16] | The discovery paper finds a larger radius of 0.89±0.09 R🜨[17] |
| Kepler-1371c | 0.64+0.07 −0.05 |
|
| Kepler-138b | 0.64±0.02 | [18] |
| 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 |
[19] |
| 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.[20] |
| Kepler-2003b (KOI-4978.02) | 0.7±0.1 | [10] |
| 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,[21] and assuming its existence, a 2023 study found a mass of 8.1±1.7 M🜨, inconsistent with such a small radius.[22]
KOI-6705.01, listed as a potential very small planet in the KOI dataset, was shown to be a false positive in 2016.[23]
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[24][25] |
Extrasolar planetesimal. Likely a remnant iron core. Radius is in the range of 1.2 – 120 km.[24] Has been disputed in a 2023 publication.[26] |
| KOI-4582.01 | 0.35[27] | |
| KOI-2298.03 | 0.36[27] | |
| KIC 1718360.01 | 0.366[28] | |
| KOI-2169.04 | 0.37[27] | |
| KOI-7174.01 | 0.37[27] | |
| KOI-8012.01 | 0.42[27] | |
| KOI-6860.01 | 0.43[27] | |
| KOI-2059.02 | 0.44[27] | |
| KOI-304.02 | 0.46[27] | |
| KOI-7793.01 | 0.46[27] | |
| KOI-2678.02 | 0.48[27] | |
| KOI-6631.01 | 0.48[27] | |
| KOI-2421.02 | 0.48[27] | |
| KOI-5974.01 | 0.49[27] | |
| KOI-3444.03 | 0.5[27] | |
| KOI-2295.01 | 0.52[27] | |
| KOI-7863.01 | 0.52[27] | |
| KOI-2612.02 | 0.53[27] | |
| KOI-4657.01 | 0.54[27] | |
| KOI-8257.01 | 0.54[27] | |
| KOI-115.03 (Kepler-105d) | 0.55+0.08 −0.07 |
[29] |
| KOI-2421.01 | 0.55[27] | |
| KOI-4097.02 | 0.55[27] | |
| KOI-7645.01 | 0.55[27] | |
| KOI-3208.01 | 0.56[27] | |
| KOI-6763.01 | 0.56[27] | |
| KOI-2859.03 | 0.57[27] | |
| KOI-4146.02 | 0.57[27] | |
| KOI-2859.04 | 0.57[27] | |
| KOI-7873.01 | 0.57[27] | |
| TOI-4307.02 | 0.57±0.14[30] | |
| KOI-2657.01 | 0.58[27] | |
| KOI-8277.01 | 0.58[27] | |
| KOI-4296.01 | 0.59[27] | |
| KOI-3196.01 | 0.59[27] | |
| KOI-5692.01 | 0.59[27] | |
| KOI-1964.01 | 0.6[27] | |
| KOI-4407.01 | 0.6[27] | |
| KOI-4871.01 | 0.6[27] | |
| KOI-5211.01 | 0.6[27] | |
| KOI-7888.01 | 0.6[27] | |
| KOI-3184.03 | 0.6[27] | |
| KOI-8183.01 | 0.6[27] | |
| KOI-3083.02 | 0.61[27] | |
| KOI-4421.01 | 0.61[27] | |
| KOI-4716.01 | 0.61[27] | |
| KOI-3102.01 | 0.61[27] | |
| KOI-7032.01 | 0.61[27] | |
| KOI-1843.03 | 0.61+0.12 −0.08 |
[31] |
| KOI-1499.02 | 0.62[27] | |
| KOI-605.02 | 0.62[27] | |
| KOI-7676.01 | 0.62[27] | |
| KOI-4849.01 | 0.62[27] | |
| KOI-365.02 | 0.62[27] | |
| KOI-7116.01 | 0.62[27] | |
| KOI-4421.02 | 0.62[27] | |
| KOI-7949.01 | 0.62[27] | |
| KOI-2029.04 | 0.63[27] | |
| KOI-6889.01 | 0.63[27] | |
| KOI-2636.02 | 0.63[27] | |
| KOI-3248.01 | 0.64[27] | |
| KOI-5213.01 | 0.64[27] | |
| KOI-6276.01 | 0.64[27] | |
| KOI-7617.01 | 0.64[27] | |
| KOI-7903.01 | 0.64[27] | |
| KOI-7925.01 | 0.64[27] | |
| KOI-8174.01 | 0.64[27] | |
| KOI-3083.03 | 0.65[27] | |
| KOI-4875.01 | 0.65[27] | |
| KOI-4808.01 | 0.65[27] | |
| KOI-6568.01 | 0.65[27] | |
| KOI-1619.01 | 0.66[27] | |
| KOI-3111.02 | 0.66[27] | |
| KOI-2859.05 | 0.66[27] | |
| KOI-3017.01 | 0.67[27] | |
| KOI-4907.01 | 0.67[27] | |
| KOI-1616.02 | 0.67[27] | |
| KOI-6299.01 | 0.67[27] | |
| KOI-8211.01 | 0.67[27] | |
| KOI-2593.02 | 0.68[27] | |
| KOI-4605.01 | 0.68[27] | |
| KOI-7832.01 | 0.68[27] | |
| KOI-7483.01 | 0.68[27] | |
| KOI-2623.02 | 0.68[27] | |
| KOI-7924.01 | 0.68[27] | |
| KOI-7628.01 | 0.69[27] | |
| KOI-4129.01 | 0.69[27] | |
| KOI-4822.01 | 0.69[27] | |
| KOI-6600.01 | 0.69[27] |
See also
[edit]References
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[...]the radii are not known but are thought to be smaller than Mercury (0.36R⊕).
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We confirmed the disintegrating-planet scenario of KOI 2700b.
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