List of largest stars

Below is a list of the largest stars, so far discovered, ordered by radius. The unit of measurement used is the radius of the Sun (695,700 km; 432,287.938 mi).

Size comparison of stars, although VV Cephei A is now thought to be smaller than Mu Cephei.

Additional methods

A few stars are in the Zodiac, and the Moon sometimes passes in front of them. This allows calculating their size by their angular size and distance. Most do not, so astronomers calculate their size by their spectral type (which gives their luminosity), distance, and brightness. Other stars can have their apparent diameter measured by an interferometer; If the star's distance is known, the real size can be found.

Caveats

These objects are extremely big, thousand to millions of times the volume of our Sun, and extremely luminous. These stars also have extended atmospheres and photospheres, and are often shrouded in dust. This makes their true size uncertain. Many of these stars vary in size and brightness (like Betelguese, Antares, Mu Cephei and VY Canis Majoris). Galaxies have different properties that affect how large their stars can be. This is why there are separate lists for galaxies.

These objects are far away, sometimes intergalactic (eg: WOH G64 is in the Large Magellanic Cloud). This makes it even harder to calculate their sizes. Most stars found will not be above 1,500 times the Sun's radius. Their mass would hardly hold together, and a lot of material would be ejected by powerful solar winds, forming the nebulae we see around them.

Astrophysicist Robert F. Wing did an in-depth look on the largest stars, recognising Antares, Betelgeuse, Mu Cephei, and VV Cephei A as well-accepted largest stars, while also looking at other stars known for cool temperatures and high brightness like VY Canis Majoris and NML Cygni. The Stefan–Boltzmann law says these stars would have a large size.^[1]

While red supergiants and hypergiants are usually the largest stars, some stars can increase their size for a short time before shrinking again. This process is called an eruption.^[2] Some eruptions, like those of Eta Carinae and V838 Monocerotis, made them much larger than the largest stars for a short time. These are listed separately.

List

Milky Way

List of the largest stars in the Milky Way Galaxy

Star name	Solar radii (Sun = 1)	Method[a]	Notes
NML Cygni	2,600[3] (1,100–2,800)[4]	L/Teff	Possibly the largest star known.[4]
Stephenson 2-18	2,200[5]	L/Teff
WOH G64	1,530
RSGC1-F01	1,450[6]–1,530+330 −424[7]	L/Teff	Located in the massive open cluster RSGC1.
Mu Cephei	1,420[8]	L/Teff	Also known as Herschel's Garnet Star.
VY Canis Majoris	1,420[9]	AD	Older estimates originally estimated the radius of VY CMa to be above 3,000 R☉,[10] or as little as 600 R☉.[11] The 1,420 R☉ measure has a margin of error of ±120 R☉.[9]
KY Cygni	1,420[8] (1,033[12])	L/Teff
AH Scorpii	1,411[13]	AD	AH Sco is a variable by nearly 3 magnitudes in the visual range, and an estimated 20% in total luminosity. The variation in diameter is not clear because the temperature also varies.
V766 Centauri Aa	1,315 ± 260[14]	AD	V766 Centauri Aa is a highly distorted star in a close binary system, losing mass to the secondary. It is also variable in temperature, thus probably also in diameter. Other estimates range from 1,060-1,160 solar radii[15] to 1,490 ± 540 solar radii.
S Persei	1,298[16]	L/Teff	A red supergiant located in the Perseus Double Cluster. Levsque et al. 2005 calculated radii of 780 R☉ and 1,230 R☉ based on K-band measurements.[8] Older estimates gave up to 2,853 R☉ based on higher luminosities.[17]
RW Cygni	1,273[18]	AD
PZ Cassiopeiae	1,259–1,336[19]	L/Teff
Westerlund 1-237	1,245[20]	L/Teff	Red supergiant within the Westerlund 1 super star cluster.
Westerlund 1-26	1,240
IRC -10414	1,200[21]	L/Teff	IRC -10414 is a rare red supergiant companion to WR 114 that has a bow shock.
HD 90587	1,181[18]	AD
RSGC1-F03	1,168[22]-1,326[20]	L/Teff	Located in the massive open cluster RSGC1.
EV Carinae	1,168[23]	L/Teff	Older estimates based on much larger distances have given higher luminosities, and consequently larger radii.[24][17]
Westerlund 1-26	1,165 or 1,221[25]	L/Teff	Very uncertain parameters for an unusual star with strong radio emission. The spectrum is variable but apparently the luminosity is not.
HD 143183 (V558 Normae)	1,147[26]	AD
V602 Carinae	1,142[18]	AD
MY Cephei	1,135[27]	L/Teff	Not to be confused with Mu Cephei (see above). Older estimates have given up to 2,440 R☉ based on much cooler temperatures.[28]
RSGC1-F02	1,128[29]-1,549[20]	L/Teff	Located in the massive open cluster RSGC1.
VX Sagittarii	1,120-1,550[30]	L/Teff	VX Sgr is a pulsating variable with a large visual range and is calculated to vary in size from 1,350 R☉ to 1,940 R☉.[31] Widely known as one of the largest known stars.[1][31]
RSGC1-F08	1,088[20]-1,146[22]	L/Teff	Located in the massive open cluster RSGC1.
Trumpler 27-1	1,073[32]	L/Teff
Orbit of Jupiter	1,064-1,173		Reported for reference
VV Cephei A	1,050[33]	EB	VV Cep A is a highly distorted star in a close binary system, losing mass to the secondary for at least part of its orbit. Data from the most recent eclipse has cast additional doubt on the accepted model of the system. Older, disproven estimates give up to 1,800 solar radii. Widely known as one of the largest known stars.[1]
SU Persei	1,039[18]	AD	In the Perseus Double Cluster
RW Leonis Minoris	1,028[34]	L/Teff	Also called CIT (California Institute of Technology) 6.
RSGC1-F12	1,005[20]	L/Teff	Located in the massive open cluster RSGC1.
Red giant phase of Van Maanen 2	1,000[35]	Evolutionary models	van Maanen 2 is now one of the closest stars to the Sun, and the closest single white dwarf.
RT Carinae	995[18]	AD
RSGC1-F13	993[20]-1,098[22]	L/Teff	Located in the massive open cluster RSGC1.
RSGC1-F09	986[22]-1,231[20]	L/Teff	Located in the massive open cluster RSGC1.
NR Vulpeculae	980[8]	L/Teff
Westerlund 1-20	965[20]	L/Teff	Red supergiant within the Westerlund 1 super star cluster.
V396 Centauri	965[18]	AD
GCIRS 7	960[36]-1,368[37]	AD	Located at the galactic center. Margin of possible error: ±92 R☉[36] or ±150 R☉.[38]
RSGC1-F11	955[20]-1,015[22]	L/Teff	Located in the massive open cluster RSGC1.
RSGC1-F10	931[22]-954[20]	L/Teff	Located in the massive open cluster RSGC1.
RSGC1-F04	914[20]-1,082[22]	L/Teff	Located in the massive open cluster RSGC1.
UY Scuti	909[39]	L/Teff
RW Cephei	900-1760	L/Teff
RSGC1-F06	885[22]-967[20]	L/Teff	Located in the massive open cluster RSGC1.
AZ Cygni	861[18]	AD
BI Cygni	850[40]-1,240[8]	L/Teff
KW Sagittarii	850[18]	AD	Older estimates have given larger radii and consequently cooler temperatures.[8]
6 Geminorum (BU Geminorum)	787[18]	AD
U Lacertae	785[32]	L/Teff
RS Persei	770[41]-831[27]	AD & L/Teff	In the Perseus Double Cluster. Margin of possible error: ±30 R☉.[41]
V915 Scorpii	760[12][42]	L/Teff
S Cephei	760[43]	AD
Psi1 Aurigae	753[18]	AD	A red supergiant similar to Antares and Betelgeuse (see below), but much further away.
Outer limits of the asteroid belt	750-900		Reported for reference
RSGC1-F07	718[20]-910[22]	L/Teff	Located in the massive open cluster RSGC1.
XX Persei	710[20]	L/Teff	Located in the Perseus Double Cluster and near the border with Andromeda.
V648 Cassiopeiae	710[8]	L/Teff
Stephenson 2-04	710[20]	L/Teff
HD 179821	704[44]	DSKE	HD 179821 may be a yellow hypergiant or a much less luminous star.
V528 Carinae	700[8]	L/Teff
The following notable stars with sizes below 700 solar radii are kept here for comparison
Antares (Alpha Scorpii A)	680[45] (varies by 19%)[46]	AD	Antares was once thought to be over 850 R☉,[47][48] but those estimates are likely to have been affected by asymmetry of the atmosphere of the star. Widely known as one of the largest known stars.[1]
Betelgeuse (Alpha Orionis)	~640[49]-697[18]	AD	Star with the third largest apparent size after R Doradus and the Sun. Another estimate gives 955±217 R☉[50] This estimate might not be reliable due to problems with measuring red supergiants in this way, but is consistent with other size estimates. Betelgeuse is a variable star so it changes size often. Widely known as one of the largest known stars.[1]
Rho Cassiopeiae	636-981[51]	AD	Yellow hypergiant, one of the rarest types of a star.
V509 Cassiopeiae (HR 8752)	590[18]	AD	Yellow hypergiant, one of the rarest types of a star.
CE Tauri	587-593[52] (-608[53])	AD	Can be occulted by the Moon, allowing accurate determination of its apparent diameter.
V382 Carinae	471[18]	AD	Yellow hypergiant, one of the rarest types of a star.
V838 Monocerotis	467[54]	L/Teff	A short time after the outburst V838 Mon was measured at 1,570 ± 400 R☉,[55] but its distance, and hence its size, have since been reduced and it proved to be a transient object that shrunk about four-fold over a few years. Like CW Leo, it has been erroneously portrayed as "Nibiru" or "Planet X" (see below).
The Pistol Star	420[56]	AD	Blue hypergiant, among the most massive and luminous stars known.
Inner limits of the asteroid belt	380		Reported for reference
Mira A (Omicron Ceti)	332-402[57]	AD	Prototype Mira variable. De beck et al. 2010 calculates 541 R☉.[58]
R Doradus	298[59]	AD	Star with the second largest apparent size after the Sun.
Orbit of Mars	297-358		Reported for reference
La Superba (Y Canum Venaticorum)	289[18]	AD	Referred to as La Superba by Angelo Secchi. Currently one of the coolest and reddest stars.
Sun's red giant phase (asymptotic giant branch)	256[60]		At this point, the Sun will engulf Mercury and Venus, and possibly the Earth although it will move away from its orbit since the Sun will lose a third of its mass. During the helium burning phase, it will shrink to 10 R☉ but will later grow again and become an unstable AGB star, and then a white dwarf after making a planetary nebula.[61][62] Reported for reference
Eta Carinae A	~240[63]		Previously thought to be the most massive single star, but in 2005 it was realized to be a binary system. η Car lacks a good surface as the wind from it is so thick. It has a "core" with a radius of 60 R☉ and the edge of the wind has a radius of 881 R☉.[64]
Orbit of Earth	215 (211-219)		Reported for reference
Solar System Habitable Zone	200-520[65] (uncertain)		Reported for reference
Orbit of Venus	154-157		Reported for reference
Epsilon Aurigae A (Almaaz)	143-358[66]	AD	ε Aur was incorrectly claimed in 1970 as the largest star with a size between 2,000 R☉ and 3,000 R☉,[67] even though it later turned out not to be an "infrared light star" but rather a dusk torus surrounding the system.
Deneb (Alpha Cygni)	99.84[18]	AD	Prototype Alpha Cygni variable.
WR 102ka	92[68]	AD	Candidate for most luminous star in the Milky Way.
Rigel	78.9		Brightest star in Orion.
Canopus (Alpha Carinae)	71	AD	Second brightest star in the night sky.
Orbit of Mercury	66-100		Reported for reference
LBV 1806-20	46-145	L/Teff	Formerly a candidate for the most luminous star in the Milky Way with 40 million L☉,[69] but the luminosity has been revised later only 2 million L☉.[70][71]
Aldebaran (Alpha Tauri)	43.06[18]	AD	Close red giant star.
Polaris (Alpha Ursae Minoris)	37.5[72]	AD	The current northern pole star and a well-known Cepheid variable.
Arcturus (Alpha Boötis)	24.25[18]	AD	Brightest star in the northern hemisphere, and a K-type red giant.
HDE 226868	20-22[73]		The supergiant companion of black hole Cygnus X-1. The black hole is around 500,000 times smaller than the star.
VV Cephei B	13[74]–25[75]		The blue main-sequence star companion of VV Cephei A.
Pollux (Beta Geminorum)	9.06 ± 0.03 [76]		The nearest giant star to Earth.
Regulus (Alpha Leonis)	4.35 ± 0.1[76]		The nearest B-type star to Earth.
Vega (Alpha Lyrae)	2.726±0.006 × 2.418±0.012[77]		One of the brightest stars in the night sky.
Sirius A (Alpha Canis Majoris A)	1.711[78]		The brightest star in the night sky.
Alpha Centauri A	1.2175[79]		Nearest G-type yellow dwarf to the Sun.
Sun	1		The largest object in the Solar System. Reported for reference

Magellanic Clouds

Star name	Solar radii (Sun = 1)	Method	Notes
WOH S281	1,376[80]	L/Teff
HV 888 (WOH S140)	1,353[81]-1,974[80]	L/Teff	Located in the Large Magellanic Cloud.
HV 11423	1,086[80]	L/Teff	Located in the Small Magellanic Cloud. HV 11423 is variable in spectral type (observed from K0 to M5), thus probably also in diameter. In October 1978, it was a star of M0I type.
SMC 018136	945[82]	L/Teff
HV 986	867
WOH G64	800[83]	L/Teff	Located in the Large Magellanic Cloud. Used to be the largest known star[84][85] before it shrunk in size.
The following notable stars with sizes below 700 solar radii are kept here for comparison
HV 2112	675-1,193[86]	L/Teff	Once thought to be a possible Thorne–Żytkow object, or a red supergiant with a neutron star core.
HD 269953	647-720		A yellow hypergiant.
HD 33579	471[87]	L/Teff	The brightest star in the Large Magellanic Cloud.
S Doradus	100-380[88]	L/Teff	A notable blue hypergiant among the most luminous stars known.
HD 37974	99[89]	L/Teff	A blue hypergiant with a dusty disk.
R136a1	28.8[90]-35.4[91]	AD	One of the most massive and luminous stars known (196 M☉ and around 5 million L☉).
BAT99-98	37.5[92]	L/Teff	One of the most massive and luminous stars known.
HD 5980 A	24[93]	L/Teff	One of the most massive and luminous stars known.

Outside the Local Group

Star name	Solar radii (Sun = 1)	Galaxy	Method	Notes
NGC 2403 V14	1,260	NGC 2403		F-type star.
Quyllur	965[94]		L/Teff	Distant red supergiant that the James Webb Space Telescope saw.
Godzilla	430-2,365[95]	Sunburst Galaxy		The most luminous star ever known, at up to 255 million times brighter than the Sun.
Mothra	271[96]			A binary star.
NGC 2363-V1	194-356[97]	NGC 2366	L/Teff

Eruptions (temporary sizes)

Star name	Solar radii (Sun = 1)	Year	Galaxy	Method	Notes
AT 2017jfs	33,000[98]	2017	NGC 4470	L/Teff
SNhunt151	16,700[99]	2014	UGC 3165	L/Teff
Orbit of Neptune	~6,500[100]				Reported for reference
M51 OT2019-1	5,486[101]	2019	Whirlpool Galaxy	L/Teff
Eta Carinae	4,319-6,032[102]	1845	Milky Way	L/Teff	During this time, it became the second-brightest star in the night sky.
Orbit of Uranus	4,121.7-4,126.3				Reported for reference
V838 Monocerotis	3,190[103]	2002	Milky Way	L/Teff
PHL 293B's luminous blue variable	1,348–1,463[104]	2002	PHL 293B	L/Teff	This star, a blue supergiant, may not exist anymore.
R71	500[105]	2012	Large Magellanic Cloud	L/Teff
Godzilla	430-2,365[95]	2015	Sunburst Galaxy	L/Teff

1. Methods for calculating the radius:

   • AD: radius determined from angular diameter and distance
   • L/T_eff: radius calculated from bolometric luminosity and effective temperature
   • DSKE: radius calculated using the disk emission
   • EB: radius determined from observations of the eclipsing binary

Related pages

• List of most massive stars
• List of most luminous stars