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List of smallest known stars

This is a list of the smallest known stars, brown dwarfs and stellar remnants, sorted by increasing size. The list is divided into sublists, and contain notable objects up to 350,000 km in radius, or 0.50 R☉, as well as all red dwarfs smaller than 0.1 R☉ and all neutron stars with accurately measured radii.

Partial list containing stars up to 0.0014 R☉.

Star name	Star radius, kilometres	Star class	Notes
SGR J1935+2154	4.35+1.95−1.35	Magnetar	Has one potential planet.
RX J0720.4−3125	4.50+0.08−0.09 – 5.38+0.13−0.14	Neutron star
Hercules X-1	8.10±0.41	Pulsar
LMC X-4	8.301±0.2
Centaurus X-3	9.178±0.130
Vela X-1	9.56±0.0
HESS J1731-347	10.40+0.86−0.78	Neutron star	Lightest neutron star ever discovered, at a mass of 0.77 M☉.
PSR J0348+0432 A	11–15	Pulsar	Has a white dwarf companion.
PSR J0437−4715	>11.1	Most stable known natural clock.
GW170817 A	11.9±0.4
GW170817 B	11.9±0.4
PSR J1906+0746	11.99–12.85
PSR J0205+6449	12	Pulsar	Pulsar located in the supernova remnant 3C 58.
RX J1856.5−3754	12.1+1.3−1.6	Neutron star	Nearest known neutron star.
PSR J2043+1711	12.13–12.96	Pulsar
PSR J1933-6211	12.15–12.98
PSR J0952–0607 A	12.245+0.685−0.315	Most massive neutron star so far discovered.
4U 1702−429	12.4±0.4	Neutron star
Vela pulsar	12.52–13.30	Pulsar
PSR J1614−2230	13±2
PSR J0348+0432	13±2
PSR J0740+6620	13.7+2.6−1.5
ZTF J1406+1422 A	14	Neutron star	Has a substellar companion orbiting it closely.
PSR J1748−2446Ad	16	Pulsar	Fasted spinning neutron star, it is constrained to a small size to avoid being torn apart, located in the star cluster Terzan 5, and potentially the largest known pulsar.

Partial list containing stars from 0.0014 to 0.0718 R☉.

Partial list containing stars from 0.0718 to 0.18 R☉.

Partial list containing stars from 0.18 to 0.287 R☉.

Partial list containing stars from 0.29 to 0.395 solar radii.

Partial list containing stars from 0.395 to 0.5 solar radii.

Star name	Star radius, kilometres	Star radius, R☉	Star class	Notes
Gliese 570 C	277,300	0.399 ± 0.028	Red dwarf
Asellus Primus B (Theta Boötis B)	279,180	0.4013±0.012
GJ 3293	281,100	0.404±0.027
Gliese 623 A	280,900	0.404 ± 0.024
Alpha Trianguli C	282,500	0.406±0.012
Gliese 908 (Lalande 46650)	284,540	0.409±0.023
EQ Pegasi A	284,540	0.409±0.016	Has one confirmed exoplanet.
Gliese 163	284,540	0.409+0.017−0.016
SDSS J001820.5−093939.2	285,930	0.411+0.090−0.011	F-type star	Among the most metal-poor stars.
Gliese 806	288,300	0.4144±0.0038	Red dwarf	Has three confirmed exoplanets.
Gliese 317	290,110	0.4170±0.0013	Has two confirmed exoplanets.
Gliese 687	291,290	0.4187+0.0066−0.0063
QS Virginis B	292,000	0.42±0.02
TOI-700	292,000	0.420±0.031
Gliese 180	294,210	0.4229±0.0047	Has two confirmed exoplanets and one unconfirmed.
AD Leonis	294,490	0.4233±0.0057
Gliese 686	297,060	0.427±0.013
Chi Ceti Bb	298,460	0.429±0.017
GJ 3634	300,000	0.43±0.03	Has one confirmed exoplanet.
Iota Ursae Majoris B	300,000	0.43
U Geminorum B	300,000	0.43±0.06
Gliese 436	300,540	0.432±0.011	Has one confirmed exoplanet.
Gliese 393	300,540	0.432±0.025
Sigma Coronae Borealis C	304,020	0.437±0.020
Kappa1 Apodis B	306,000	0.44±0.06	Subdwarf O star
WR 93b	306,000	0.44	Wolf-Rayet
Gliese 832	307,500	0.442±0.018	Red dwarf
Alpha Caeli B	313,000	0.45
Gliese 367 (Anañuca)	317,930	0.457±0.013	Has three confirmed exoplanets.
Gliese 588	320,000	0.46±0.019
Iota Ursae Majoris C	320,000	0.46
HD 147379 B	320,000	0.460±0.008
Gliese 849	322,800	0.464±0.018
BAT99-123 (Brey 93)	327,000	0.47	Wolf-Rayet
Gliese 176	329,760	0.474±0.015	Red dwarf
Lacaille 9352	329,760	0.474±0.008
Tau Boötis B	333,900	0.48±0.05
Gliese 752 A	334,630	0.481±0.014
UScoCTIO 108 A	336,720	0.484	Brown dwarf
Gliese 526	338,810	0.487±0.008	Red dwarf
UX Ursae Majoris B	345,070–484,900	0.496–0.697
Theta Persei Ab	346,500	0.498±0.017
GJ 3470 (Kaewkosin)	347,150	0.499±0.021
Kappa Reticuli B	347,900	0.50
TOI-2119	347,900	0.500±0.015
Gliese 22 A	~350,000	~0.5

Type	Star name	RadiusSolar radii(Sun = 1)	RadiusJupiter radii(Jupiter = 1)	RadiusEarth radii(Earth = 1)	Radius(km / mi)	Date	Notes
Red dwarf	EBLM J0555−57Ab	0.084	0.84	9.41	60,000 km (37,000 mi)	2017	The red dwarf stars are considered the smallest stars known, and representative of the smallest star possible.
Brown dwarf	ZTF J1406+1422 B	0.029	0.282	3.16	20,200 kilometres (12,600 mi)	2022	Brown dwarfs are not massive enough to build up the pressure in the central regions to allow nuclear fusion of hydrogen into helium. They are best described as extremely massive gas giants that were not able to ignite into a hydrogen-fusing star.
White dwarf	ZTF J1901+1458	0.0031	0.030	0.34	2,140 km (1,330 mi)	2021	White dwarfs are stellar remnants produced when a star with around 8 solar masses or less sheds its outer layers into a planetary nebula. The leftover core becomes the white dwarf. It is thought that white dwarfs cool down over quadrillions of years to produce a black dwarf.
Neutron star	RX J0720.4−3125	0.0000064683 – 0.0000077332	0.00006294 – 0.00007525	0.0007055 – 0.0008435	4.50+0.08−0.09 – 5.38+0.13−0.14	2012	Neutron stars are stellar remnants produced when stars with around 9 solar masses or more explode in supernovae at the ends of their lives. They are usually produced by stars with less than 20 solar masses, although a more massive star may produce a neutron star in certain cases.

Red dwarfs are considered the smallest stars known that are active fusion stars, and are the smallest stars possible that is not a brown dwarf.

Star name	Date	RadiusSolar radii(Sun = 1)	RadiusJupiter radii(Jupiter = 1)	Radiuskm(mi)	Notes
EBLM J0555−57Ab	2017-	0.084	0.84	60,000 km (37,000 mi)	This star has a size comparable to that of Saturn.
2MASS J0523−1403	2013-2017	0.102	1.01	70,600 km (43,900 mi)	Lowest mass main sequence star as of 2020.
OGLE-TR-122B	2005-2013	0.117	1.16	81,100 km (50,400 mi)

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