List of smallest exoplanets

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

List

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

Exoplanet Radius () Notes and references Mass ()SDSS J0845+2257 b0.01-0.013Planetesimal, enhanced in iron and silicates. WD 1145+017 b ~0.03 Disintegrating planetesimal, likely one of several orbiting its star. Likely about one-tenth the mass of Ceres and ~200 km in radius.~0.000016<ref name="Rappaport2016"/> Ceres 0.0742 Shown for comparison Pluto 0.1863 Shown for comparison Moon 0.2725 Shown for comparison Kepler-37b <ref name="Bonomo2023"/> Smallest known exoplanet. <0.79 BD+05 4868 Ab ~0.314Disintegrating planet, radius is just an estimate. 0.02 PSR B1257+12 b (Draugr) ~0.338 Least massive known exoplanet, at 0.02 Earth masses. Radius predicted from mass-radius relationship. 0.02 Kepler-1520b ≲0.36 Disintegrating planets with poorly known radii, all thought to be smaller than Mercury. KOI-2700b K2-22b Mercury 0.3826 Shown for comparison Kepler-879c Kepler-444b Ganymede 0.413 Shown for comparison Kepler-158d Kepler-102b Kepler-444c Kepler-1971b (KOI-4777.01) Kepler-1489c Kepler-1994b Kepler-1308b Kepler-444d Mars 0.5325 Shown for comparison Kepler-62c Kepler-444e Gliese 238 b Kepler-102c Kepler-42d Kepler-1583b Kepler-1998b Kepler-963c Kepler-974c (KOI-1843.03) Candidate. , the Exoplanet Archive lists it as confirmed. Kepler-1087b K2-89b Kepler-1877b 0.624 Barnard's Star e ~0.637 Radius predicted from mass-radius relationship. Least massive exoplanet detected by radial velocity and possibly smallest known within 10 parsecs. K2-137b The discovery paper finds a larger radius of Kepler-1371c Kepler-138b Kepler-1130d 0.645 Kepler-1351b Kepler-1542c Kepler-271d Kepler-431c 0.668 Kepler-1558b LHS 1678 b K2-116b Kepler-141b K2-297b (EPIC 201497682 b) Proxima Centauri d ~0.692 Radius predicted from mass-radius relationship. Barnard's Star d ~0.694 Radius predicted from mass-radius relationship. Gliese 367 b (Tahay) Smallest exoplanet within 10 parsecs with a measured radius.0.633 Kepler-2003b (KOI-4978.02) Kepler-378c

Excluded objects Kepler-37e is listed with a radius of in the Exoplanet Archive based on KOI data, but the existence of this planet is doubtful, and assuming its existence, a 2023 study found a mass of , inconsistent with such a small radius.

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

Candidate planets

Below is a list of candidate planets below . These planets have yet to be confirmed.

Kepler object of interest Radius () Notes and references SDSS J1228+1040 b(SDSS J122859.92+104033.0 b, WD 1226+110 b) 0.010 Extrasolar planetesimal. Likely a remnant iron core. Radius is in the range of 1.2120 km. Has been disputed in a 2023 publication. TRAPPIST-1i KOI-4582.01 0.35 KOI-2298.03 0.36 KOI-2169.04 0.37 KOI-7174.01 0.37 KOI-8012.01 0.42 KOI-6860.01 0.43 KOI-2059.02 0.44 KOI-304.02 0.46 KOI-7793.01 0.46 KOI-2678.02 0.48 KOI-6631.01 0.48 KOI-2421.02 0.48 KOI-5974.01 0.49 KOI-3444.03 0.5 KOI-2295.01 0.52 KOI-7863.01 0.52 KOI-2612.02 0.53 KOI-4657.01 0.54 KOI-8257.01 0.54 KOI-115.03 (Kepler-105d) KOI-2421.01 0.55 KOI-4097.02 0.55 KOI-7645.01 0.55 KOI-3208.01 0.56 KOI-6763.01 0.56 KOI-2859.03 0.57 KOI-4146.02 0.57 KOI-2859.04 0.57 KOI-7873.01 0.57 TOI-4307.02 KOI-2657.01 0.58 KOI-8277.01 0.58 KOI-4296.01 0.59 KOI-3196.01 0.59 KOI-5692.01 0.59 KOI-1964.01 0.6 KOI-4407.01 0.6 KOI-4871.01 0.6 KOI-5211.01 0.6 KOI-7888.01 0.6 KOI-3184.03 0.6 KOI-8183.01 0.6 KOI-3083.02 0.61 KOI-4421.01 0.61 KOI-4716.01 0.61 KOI-3102.01 0.61 KOI-7032.01 0.61 KOI-1499.02 0.62 KOI-605.02 0.62 KOI-7676.01 0.62 KOI-4849.01 0.62 KOI-365.02 0.62 KOI-7116.01 0.62 KOI-4421.02 0.62 KOI-7949.01 0.62 KOI-2029.04 0.63 KOI-6889.01 0.63 KOI-2636.02 0.63 KOI-3248.01 0.64 KOI-5213.01 0.64 KOI-6276.01 0.64 KOI-7617.01 0.64 KOI-7903.01 0.64 KOI-7925.01 0.64 KOI-8174.01 0.64 KOI-3083.03 0.65 KOI-4875.01 0.65 KOI-4808.01 0.65 KOI-6568.01 0.65 KOI-1619.01 0.66 KOI-3111.02 0.66 KOI-2859.05 0.66 KOI-3017.01 0.67 KOI-4907.01 0.67 KOI-1616.02 0.67 KOI-6299.01 0.67 KOI-8211.01 0.67 KOI-2593.02 0.68 KOI-4605.01 0.68 KOI-7832.01 0.68 KOI-7483.01 0.68 KOI-2623.02 0.68 KOI-7924.01 0.68 KOI-7628.01 0.69 KOI-4129.01 0.69 KOI-4822.01 0.69 KOI-6600.01 0.69

See also List of largest exoplanets List of exoplanet extremes Lists of exoplanets

References