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. Some of these are unconfirmed and/or controversial.

List

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, 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) 		0.0101+0.0504
−0.0085[3][4] 		Extrasolar planetesimal. Likely a remnant iron core. Radius is in the range of 1.2 – 120 km.[3]
PSR B1828-11 b 0.016 Unconfirmed, controversial[1]
Ceres 0.0742 Shown for comparison
WD 1145+017 b ~0.15 Extrasolar planetesimal.[5]
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
Kepler-37e 0.37±0.18 Dubious[11]
Mercury 0.3826 Shown for comparison
Kepler-444b 0.403+0.016
−0.014 		[12]
Kepler-102b 0.460±0.026 [7]
Kepler-444c 0.497+0.021
−0.017 		[12]
Kepler-1971b (KOI-4777.01) 0.51±0.03 [13]
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]
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
K2-116b 0.69±0.04
Kepler-141b 0.69±0.05
K2-297b (EPIC 201497682 b) 0.692+0.059
−0.048
LHS 1678 b 0.696±0.044
Gliese 367 b (Tahay) 0.699±0.024 Smallest known exoplanet within 10 parsecs.[17]
Kepler-1349b 0.700+0.630
−0.110
Kepler-378c 0.70±0.05

TESS candidates

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

TESS object of interest Radius (R🜨) Notes and references
TOI-4307.02 0.587936684757796±0.16721696[18]
TOI-486.01 0.633718±0.0589259[18]

Kepler candidates

Below shows a list of Kepler 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[19]
KOI-2298.03 0.36[19]
KOI-2169.04 0.37[19]
KOI-7174.01 0.37[19]
KOI-8012.01 0.42[19]
KOI-6860.01 0.43[19]
KOI-2059.02 0.44[19]
KOI-304.02 0.46[19]
KOI-7793.01 0.46[19]
KOI-2678.02 0.48[19]
KOI-6631.01 0.48[19]
KOI-2421.02 0.48[19]
KOI-5974.01 0.49[19]
KOI-3444.03 0.5[19]
KOI-2295.01 0.52[19]
KOI-7863.01 0.52[19]
KOI-2612.02 0.53[19]
KOI-4657.01 0.54[19]
KOI-8257.01 0.54[19]
KOI-115.03 (Kepler-105d) 0.55+0.08
−0.07 		[20]
KOI-2421.01 0.55[19]
KOI-4097.02 0.55[19]
KOI-7645.01 0.55[19]
KOI-3208.01 0.56[19]
KOI-6763.01 0.56[19]
KOI-2859.03 0.57[19]
KOI-4146.02 0.57[19]
KOI-2859.04 0.57[19]
KOI-7873.01 0.57[19]
KOI-2657.01 0.58[19]
KOI-8277.01 0.58[19]
KOI-4296.01 0.59[19]
KOI-3196.01 0.59[19]
KOI-5692.01 0.59[19]
KOI-1964.01 0.6[19]
KOI-4407.01 0.6[19]
KOI-4871.01 0.6[19]
KOI-5211.01 0.6[19]
KOI-7888.01 0.6[19]
KOI-3184.03 0.6[19]
KOI-8183.01 0.6[19]
KOI-3083.02 0.61[19]
KOI-4421.01 0.61[19]
KOI-4716.01 0.61[19]
KOI-3102.01 0.61[19]
KOI-7032.01 0.61[19]
KOI-1843.03 0.61+0.12
−0.08 		[21]
KOI-1499.02 0.62[19]
KOI-605.02 0.62[19]
KOI-7676.01 0.62[19]
KOI-4849.01 0.62[19]
KOI-365.02 0.62[19]
KOI-7116.01 0.62[19]
KOI-4421.02 0.62[19]
KOI-7949.01 0.62[19]
KOI-2029.04 0.63[19]
KOI-6889.01 0.63[19]
KOI-2636.02 0.63[19]
KOI-3248.01 0.64[19]
KOI-5213.01 0.64[19]
KOI-6276.01 0.64[19]
KOI-7617.01 0.64[19]
KOI-7903.01 0.64[19]
KOI-7925.01 0.64[19]
KOI-8174.01 0.64[19]
KOI-3083.03 0.65[19]
KOI-4875.01 0.65[19]
KOI-4808.01 0.65[19]
KOI-6568.01 0.65[19]
KOI-1619.01 0.66[19]
KOI-3111.02 0.66[19]
KOI-2859.05 0.66[19]
KOI-3017.01 0.67[19]
KOI-4907.01 0.67[19]
KOI-1616.02 0.67[19]
KOI-6299.01 0.67[19]
KOI-8211.01 0.67[19]
KOI-2593.02 0.68[19]
KOI-4605.01 0.68[19]
KOI-7832.01 0.68[19]
KOI-7483.01 0.68[19]
KOI-2623.02 0.68[19]
KOI-7924.01 0.68[19]
KOI-7628.01 0.69[19]
KOI-4129.01 0.69[19]
KOI-4822.01 0.69[19]
KOI-6600.01 0.69[19]

See also

References

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  2. ^ "Planetary Systems Composite Data". NASA Exoplanet Archive. Retrieved 16 July 2023.
  3. ^ a b Manser, Christopher J.; et al. (5 April 2019). "A planetesimal orbiting within the debris disc around a white dwarf star". Science. 364 (6435): 66–69. arXiv:1904.02163. Bibcode:2019Sci...364...66M. doi:10.1126/science.aat5330. ISSN 0036-8075. PMID 30948547. S2CID 96434522.
  4. ^ "Planet SDSS J1228+1040 b". Extrasolar Planets Encyclopaedia. Retrieved 2019-08-05.
  5. ^ Vanderburg, Andrew; John Asher Johnson; Rappaport, Saul; Bieryla, Allyson; Irwin, Jonathan; John Arban Lewis; Kipping, David; Brown, Warren R.; Dufour, Patrick; Ciardi, David R.; Angus, Ruth; Schaefer, Laura; Latham, David W.; Charbonneau, David; Beichman, Charles; Eastman, Jason; McCrady, Nate; Wittenmyer, Robert A.; Wright, Jason T. (2015). "A disintegrating minor planet transiting a white dwarf". Nature. 526 (7574): 546–549. arXiv:1510.06387. Bibcode:2015Natur.526..546V. doi:10.1038/nature15527. PMID 26490620. S2CID 4451207.
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  7. ^ a b c Bonomo, A. S.; Dumusque, X.; et al. (April 2023). "Cold Jupiters and improved masses in 38 Kepler and K2 small-planet systems from 3661 high-precision HARPS-N radial velocities. No excess of cold Jupiters in small-planet systems". Astronomy & Astrophysics. arXiv:2304.05773. doi:10.1051/0004-6361/202346211. S2CID 261556620.
  8. ^ "Exoplanet-catalog".
  9. ^ Ansdell, M.; Hirano, T.; Gaidos, E. (2019). "Monitoring of the D doublet of neutral sodium during transits of two 'evaporating' planets". Monthly Notices of the Royal Astronomical Society. 485 (3): 3876–3886. arXiv:1903.06217. doi:10.1093/mnras/stz693. [...]the radii are not known but are thought to be smaller than Mercury (0.36R⊕).
  10. ^ Garai, Z. (2018). "Light-curve analysis of KOI 2700b: The second extrasolar planet with a comet-like tail". Astronomy & Astrophysics. 611: A63. arXiv:1712.07461. Bibcode:2018A&A...611A..63G. doi:10.1051/0004-6361/201629676. S2CID 118885868. We confirmed the disintegrating-planet scenario of KOI 2700b.
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  17. ^ Goffo, Elisa; Gandolfi, Davide; et al. (July 2023). "Company for the ultra-high density, ultra-short period sub-Earth GJ 367 b: discovery of two additional low-mass planets at 11.5 and 34 days". The Astrophysical Journal Letters. 955: L3. arXiv:2307.09181. doi:10.3847/2041-8213/ace0c7.
  18. ^ a b "NASA Exoplanet Archive". NASA Exoplanet Archive. Retrieved 16 June 2023.
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  20. ^ "Kepler-105". NASA Exoplanet Archive. Retrieved 12 December 2021.
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