The Sun vs Largest Stars Size Comparison

 

Below are lists of the largest stars currently known, ordered by radius and separated into categories by galaxy. The unit of measurement used is the radius of the Sun (approximately 695,700 km; 432,300 mi).

Overview

Although red supergiants are often considered the largest stars, some other star types have been found to temporarily increase significantly in radius, such as during LBV eruptions or luminous red novae. Luminous red novae appear to expand extremely rapidly, reaching thousands to tens of thousands of solar radii within only a few months, significantly larger than the largest red supergiants.

Some studies use models that predict high-accreting Population III or Population I supermassive stars (SMSs) in the very early universe could have evolved "red supergiant protostars". These protostars are thought to have accretion rates larger than the rate of contraction, resulting in lower temperatures but with radii reaching up to many tens of thousands of R_☉, comparable to some of the largest known black holes.

Angular diameters

The angular diameters of stars can be measured directly using stellar interferometry. Other methods can use lunar occultations or from eclipsing binaries, which can be used to test indirect methods of finding stellar radii. Only a few supergiants can be occulted by the Moon, including Antares and 119 Tauri. Examples of eclipsing binaries are Epsilon Aurigae (Almaaz), VV Cephei, and V766 Centauri (HR 5171). Angular diameter measurements can be inconsistent because the boundary of the very tenuous atmosphere (opacity) differs depending on the wavelength of light in which the star is observed.

Uncertainties remain with the membership and order of the lists, especially when deriving various parameters used in calculations, such as stellar luminosity and effective temperature. Often stellar radii can only be expressed as an average or be within a large range of values. Values for stellar radii vary significantly in different sources and for different observation methods.

All the sizes stated in these lists have inaccuracies and may be disputed. The lists are still a work in progress and parameters are prone to change.

Caveats

Various issues exist in determining accurate radii of the largest stars, which in many cases do display significant errors. The following lists are generally based on various considerations or assumptions; these include:

• Stellar radii or diameters are usually derived only approximately using the Stefan–Boltzmann law for the deduced stellar luminosity and effective surface temperature.
• Stellar distances, and their errors, for most stars, remain uncertain or poorly determined.
• Many extended supergiant atmospheres also significantly change in size over time, regularly or irregularly pulsating over several months or years as variable stars. This makes adopted luminosities poorly known and may significantly change the quoted radii.
• Other direct methods for determining stellar radii rely on lunar occultations or from eclipses in binary systems. This is only possible for a very small number of stars.
• Many distance estimates for red supergiants come from stellar cluster or association membership, because it is difficult to calculate accurate distances for red supergiants that are not part of any cluster or association.
• In these lists are some examples of extremely distant extragalactic stars, which may have slightly different properties and natures than the currently largest known stars in the Milky Way. For example, some red supergiants in the Magellanic Clouds are suspected to have slightly different limiting temperatures and luminosities. Such stars may exceed accepted limits by undergoing large eruptions or changing their spectral types over just a few months (or potentially years).

Milky Way

List of the largest known stars in the Milky Way

Star name	Solar radius (R☉)	Method[a]	Notes
Orbit of Saturn	2,047–2,049.9[10][b]		Reported for reference
Theoretical limit of star size (Milky Way)	≳1,700[11]	L/Teff	Estimated by measuring the fraction of red supergiants at higher luminosities in a large sample of supernova progenitor candidates. Assumes an effective temperature of 3,605 K. Reported for reference
WOH G64 A (For comparison)	1,540[12][13][14][15][16] ± 77[12]	L/Teff	Located in the Large Magellanic Cloud. Possibly the largest known star.[12][13][17][14]
RSGC1-F01 (FMR2006 1)	1,530+330 −424[18]	L/Teff
VX Sagittarii	1,456±108 – 1,556±110[19]	AD	Widely recognized as being among the largest known stars.[20] The lower value is the mean radius during quiescent pulsation cycle, with an amplitude of 60 R☉, while the higher value is the mean radius during the active pulsation cycle, with an amplitude of 197 R☉. Reached a maximum radius of 1,798±127 R☉ in September 2019. During 2020 to 2021, the star underwent a great dimming event similar to Betelgeuse.[19]
RSGC1-F04 (FMR2006 4)	1,422+305 −390[18]	L/Teff
VY Canis Majoris	1,420±120[21][22][23]	AD	An extreme oxygen-rich red hypergiant that has experienced two dimming periods in the 20th century, where the star became dimmer by up to 2.5 magnitudes.[24] Potentially the largest known star.[22] There is a possibility that this size might be a bit overestimated (on the order of 1 sigma). Hence, the quoted radius might be just an upper limit.[21]
AH Scorpii	1,411±124[25][26]	AD	Its angular diameter was re-measured at 5.05 ± 0.5 mas in 2023, which would yield a smaller radius of 1,227 R☉.[27]
CD–34°11794	1,409[28]	L/Teff	Oxygen-rich[29] red supergiant[30] and OH/IR star.[31]
RSGC1-F06 (FMR2006 6)	1,382+298 −384[18]	L/Teff
S Persei	1,364±6[32]	AD	Oxygen-rich[29][33] red supergiant.[34] Also called a hypergiant.[35]
Stephenson 2 DFK 2	1,300 ± 300[18]	L/Teff
Stephenson 2 DFK 49	1,300 ± 300[18]	L/Teff	A K-type star similar to the yellow hypergiant IRC +10420 that has left its red supergiant stage.[18]
HD 143183 (V558 Normae)	1,261[28]	L/Teff
PZ Cassiopeiae	1,259 – 1,336[36]	L/Teff & AD
RSGC1-F10 (FMR2006 10)	1,246+264 −337[18]	L/Teff
V354 Cephei	1,245[28]	L/Teff
Westerlund 1 W237 (Westerlund 1 BKS B)	1,241±70,[37] 888[28]	L/Teff	Possibly a foreground giant.[38]
ST Cephei	1,218[28]	L/Teff
IRC -30312	1,204[28]	L/Teff
IRC -10414	~1,200[39]	L/Teff
RSGC1-F05 (FMR2006 5)	1,185+254 −325[18]	L/Teff
V517 Monocerotis	1,196+80 −159[40] – 1,208[28]	L/Teff
GCIRS 7	1,170±60,[41] 1,359,[42] 1,368[43]	AD & L/Teff
Westerlund 1 W26 (Westerlund 1 BKS AS)	1,165±58–1,221±120[37]	L/Teff
[A72c] 16	1,157[28]	L/Teff
WY Velorum A	1,157[28]	L/Teff	A symbiotic binary.[44]
RSGC1-F08 (FMR2006 8)	1,150+234 −297[18]	L/Teff
IRC -30303	1,147[28]	L/Teff
RSGC1-F02 (FMR2006 2)	1,128+238 −303[18]	L/Teff
Orbit of Jupiter	1,114.5–1,115.8[10][b]		Reported for reference
V582 Cassiopeiae	1,111[28]	L/Teff
RW Cygni	1,103+251 −177[45]	AD
RW Cephei	1,100±40[46]	AD	A K-type hypergiant star that experienced a "great dimming" event in 2022, similar to Betelgeuse.
RT Carinae	1,090[47]	L/Teff
UU Persei	1,079+9 −8[40]	L/Teff
LL Pegasi	1,070[48]	L/Teff
HD 126577	1,066+9 −32[40]	L/Teff
V766 Centauri Aa	1,060–1,160[49]	?	V766 Centauri Aa is a rare variable yellow hypergiant.
HaroChavira 1	1,058[50]	L/Teff
EV Carinae	1,057[28]	L/Teff	Red supergiant.[51] An older study suggests an extremely high radius of 2,877 R☉.[52]
CM Velorum	1,048[28] – 1,416.24+0.40 −0.96[40]	L/Teff
AG Camelopardalis	1,048[28]	L/Teff
SU Persei	1,044+31 −21 – 1,139+34 −23,[32]	AD
SW Cephei	1,035+75 −120[53]	AD
KY Cygni	1,032[50]	L/Teff
RSGC1-F11 (FMR2006 11)	1,032+210 −267[18]	L/Teff
BC Cygni	1,031[50] – 1,187+34 −37,[40] 1,062[28]	L/Teff	A more detailed but older study gives values of 1,081 R☉ (856–1,375) for the year 2000, and 1,303 R☉ (1,021–1,553) for the year 1900.[54]
MY Cephei	1,028 ± 169 – 1,138 ± 387[55][c]	L/Teff
V346 Puppis	1,025[56]	L/Teff
V530 Cassiopeiae	1,017[28]	L/Teff
V602 Carinae	1,015[57]	AD
VV Cephei A	1,015[58]	AD	A red supergiant star orbited by a smaller B-type main-sequence star with a radius estimated between 13[59] and 25 R☉.[60] Widely recognised as being among the largest known stars.[20] Another estimate give a radius of 660 R☉[28] based on the Gaia DR3 distance of 1 kpc.[40]
U Lacertae A	1,013[28]	L/Teff
RSGC1-F13 (FMR2006 13)	1,017+221 −286[18]	L/Teff
KW Sagittarii	1,009±142[25][26]	AD
Ve 4-64	1,007[28]	L/Teff
RSGC1-F07 (FMR2006 7)	1,007+215 −276[18]	L/Teff
V349 Carinae	1,002+12 −74[40]	L/Teff
V674 Cephei	999[28]	L/Teff
RSGC1-F09 (FMR2006 9)	996+210 −269[18]	L/Teff
CZ Hydrae	990[61]	L/Teff
IRAS 18111-2257	~990 – 1,200[62]	L/Teff	Estimated based on the bolometric luminosity (14,000–20,000 L☉) and assumed effective temperature of 2,000 K. Another period-luminosity-derived luminosity for this star results in a radius of 1,730 R☉.[62]
CIT 11 (V3060 Cygni)	982[28]	L/Teff
V381 Cephei Aa	977[28]	L/Teff
MSX6C G086.5890–00.7718	(975+175 −183 – 1,035+186 −158)[63] – 1,196.91+6.31 −6.35[40]	L/Teff	Lower values based on the Gaia DR3 effective temperature and the luminosity of Levesque et al. (2005) and that of Messineo & Brown (2019). Higher value based on the GSP Phot-Aeneas library using BR/RP spectra in Gaia DR3.
Stephenson 2 DFK 3	970 ± 210[18]	L/Teff
V3953 Sagittarii (IRC −30398)	970[64]	L/Teff
V396 Centauri	965[28]	L/Teff
UW Aquilae	964[28]	L/Teff
RSGC1-F12 (FMR2006 12)	955+204 −262[18]	L/Teff
RSGC1-F03 (FMR2006 3)	942+179 −222[18]	L/Teff
V398 Cassiopeiae (HD 240275)	941[28]	L/Teff
IRC +60342	940[28]	L/Teff
ψ1 Aurigae	934[28] – 1,004+369 −234[65]	L/Teff
GX Monocerotis	931[64]	L/Teff
V645 Cephei	920[28]	L/Teff
S Cassiopeiae	920[64]	L/Teff	One of the coolest known stars, at an effective temperature of 1,800 K (1,500 °C).
NV Aurigae (IRC +50137)	918[64]	L/Teff
Stephenson 2 DFK 5	910 ± 180[18]	L/Teff
UY Scuti	909[28]	L/Teff	Once thought to be 1,708 ± 192 R☉[25] or 1,943 R☉.[52]
NR Vulpeculae	908[28] – 923+62 −50[53]	L/Teff
KU Andromedae (IRC +40004)	900[66] – 1,040[64]	L/Teff
V774 Sagittarii	889[28]	L/Teff
V923 Centauri	881[28]	L/Teff
IRAS 20341+4047	880[28]	L/Teff
IRAS 17418−2713	880[67]	L/Teff
V540 Sagittarii	880[28]	L/Teff
V386 Cephei	879[28]	L/Teff
Trumpler 27-1 (CD–33°12241)	876+5 −12[40]	?
T Lyrae	880[64]	L/Teff
TYC 3996-552-2	870[28]	L/Teff
V1417 Aquilae	900[68]	L/Teff
V1300 Aquilae (IRC −10529)	860[66] – 1,100[64]	L/Teff
Westerlund 1 W20 (Westerlund 1 BKS D)	858±48[37]	L/Teff
FX Serpentis	857[56]	L/Teff
AZ Cygni	856+20 −14 – 927+21 −15[32]	AD	Estimated based on data from the CHARA array. Other radii of 890+21 −15 R☉ (2014), 895+21 −15 R☉ (2015) and 890+21 −15 R☉ (2016) are calculated based on the same data.[32]
V348 Velorum	855[28]	L/Teff
BI Cygni	852+12 −9 – 908+12 −10[32]	AD
TW Carinae	835[28]	L/Teff
V358 Cassiopeiae	835[28]	L/Teff
VLH96 A	833[69]	L/Teff
DO 26226	826[28]	L/Teff
HD 155737	823[28]	L/Teff
6 Geminorum	821[32]	L/Teff
RW Leonis Minoris	820[70] – 1,000[64]	L/Teff
HaroChavira 2	813[50]	L/Teff
HD 300933	806[28]	L/Teff
[W61c] R 53	801[28]	L/Teff
RT Ophiuchi	801±217[71]	AD
HD 95687	797[28]	L/Teff
BO Carinae	790±158[47]	L/Teff
HD 62745	790[28]	L/Teff
WX Piscium	790[72] – 1,000[64]	L/Teff
VR5–7	775 ± 65[73]	L/Teff
T Cancri	770[56]	L/Teff
V Cygni	770[68]	L/Teff
BD+63 3	770[28]	L/Teff
CL Carinae	770[28]	L/Teff
RS Persei	770±30,[74] 775+110 −85[53]	AD
V355 Cephei	770±154[47] – 790[28]	L/Teff
BD+63 270	769[28]	L/Teff
V644 Cephei	765[28]	L/Teff
Garnet Star (μ Cephei)	762[75]	AD	Widely recognised as being among the largest known stars.[20] Might be the largest star visible to the naked eye.[76]
BM VIII 11	754[28]	L/Teff
[SLN74] 2130	752[28]	L/Teff
IRAS 10176-5802	751.2+0.4 −0.6[40] – (793+281 −152–849+172 −133)[63]	L/Teff	Lower value based on the GSP Phot-Aeneas library using BR/RP spectra in Gaia DR3. Higher values based on the Gaia DR3 effective temperature and the luminosity of Levesque et al. (2005) and that of Messineo & Brown (2019).
HD 303250	750±150[47]	L/Teff
V384 Persei	750[66] – 940[64]	L/Teff
V466 Persei	750[70]	L/Teff
V Coronae Borealis	750[66]	L/Teff
GY Aquilae	748[26] – 920[77]	AD
UU Pegasi	742±193[71]	AD
IM Cassiopeiae	740[28]	L/Teff
GY Camelopardalis	740[66]	L/Teff
R Andromedae	730[66]	L/Teff
RSGC3-S3	730 ± 150[18]	L/Teff
TT Centauri	740[64]	L/Teff
Stephenson 2 DFK 10	730[18]	L/Teff
V1259 Orionis	730[61]	L/Teff
RSGC3-S15	730 ± 140[18]	L/Teff
VdBH 222#566	725[78]	L/Teff	May be larger at 912 R☉, however this is unlikely due to the luminosity not matching with the H-R diagram where the temperature was calculated.
HD 105563 A	723[28]	L/Teff
Westerlund 1 W75 (Westerlund 1 BKS E)	722±36[37]	L/Teff
AI Volantis	720[66]	L/Teff
V1111 Ophiuchi (IRC +10365)	720[66] – 900[64]	L/Teff
XX Persei	718+80 −56[53]	AD
RX Telescopii	716[28]	L/Teff
V Camelopardalis	716±185[71]	AD
CD–61°3575	716[28]	L/Teff
S Cephei	715[56]	L/Teff
AS Cephei	713[28]	L/Teff
V770 Cassiopeiae (BD+60 299)	713[28]	L/Teff
AZ Cephei	712[28]	L/Teff
R Leporis (Hind's Crimson Star)	710 – 910[79]	AD
MZ Puppis	708[28]	L/Teff
GP Cassiopeiae	707[28] – 771.74+0.23 −0.86[40]	L/Teff
GCIRS 12N	703 ± 107[73]	L/Teff
RU Herculis	700 ± 90[80]	L/Teff
V528 Carinae	700±140[47]	L/Teff
The following well-known stars are listed for the purpose of comparison.
Antares (α Scorpii A)	680[81]	AD	Fourteenth brightest star in the night sky.[82] Widely recognised as being among the largest known stars.[20]
Betelgeuse (α Orionis)	640,[83] 764+116 −62,[84] 782 ± 55[85]	AD & SEIS	Tenth brightest star in the night sky.[82] Widely recognised as being among the largest known stars,[20] radius decreased to ~500 R☉ during the 2020 great dimming event.[86]
R Horologii	630[66]	L/Teff	A red giant star with one of the largest ranges in brightness known of stars in the night sky visible to the unaided eye. Despite its large radius, it is less massive than the Sun.
V382 Carinae	616±69[87]	AD	A yellow hypergiant, one of the rarest types of stars.
119 Tauri (CE Tauri, Ruby Star)	587 – 593[88]	AD
ρ Cassiopeiae	564±67 or 700±112[89]	AD	A yellow hypergiant star, similar to V382 Carinae, that is also visible to the naked eye.
CW Leonis	560[90]	L/Teff	The nearest carbon star.
V838 Monocerotis	464[91]	L/Teff	During the 2002 Red Nova, the star's radius may have increased up to 3,190 R☉.[92]
V509 Cassiopeiae	449±20[87]	AD	A variable yellow hypergiant whose size varied from around 680 R☉ in 1950–1970 to 910 R☉ in 1977, and later decreased to 390 R☉ in the 1990s.[93]
Mira (ο Ceti A)	332–402[94]	AD	Prototype of the Mira variables.
Orbit of Mars	322–323.1[10][b]		Reported for reference
La Superba (Y Canum Venaticorum)	315[95]	L/Teff
Pistol Star (V4647 Sagittarii)	308[96]	L/Teff	One of the most luminous stars known.
R Doradus	298 ± 21[97]	AD	The extrasolar star with the largest apparent size.
Rasalgethi (α Herculis A)	284±60 (264–303)[98]	L/Teff
Cygnus OB2#12	246[99]	?	One of the most massive and luminous stars known.
Orbit of Earth (~1 AU)	214[10][b]		Reported for reference
Suhail (λ Velorum)	211±6[100]	AD
Wezen (δ Canis Majoris)	188[95]	L/Teff	Thirty-sixth brightest star in the night sky.[82]
Enif (ε Pegasi)	178[95]	L/Teff
Orbit of Venus	158.6[10][b]		Reported for reference
η Carinae A	128 – 742[101]	OD	During the 1843 Great Eruption, the star's radius may have increased up to 4,319–6,032 R☉.[102]
Deneb (α Cygni)	107[103][d] – 203±17[104]	AD & ?	Eighteenth brightest star in the night sky.[82]
Orbit of Mercury	82.9–84.6[10][b]		Reported for reference
Rigel (β Orionis A)	74.1+6.1 −7.3[105]	AD	Seventh brightest star in the night sky.
Canopus (α Carinae)	73.3[106]	AD	Second brightest star in the night sky.
Gacrux (γ Crucis)	73[107]	L/Teff	Twenty-sixth brightest star in the night sky.
Polaris (α Ursae Minoris Aa)	46.27±0.42[108]	AD	The current star in the North Pole. It is a Classical Cepheid variable, and the brightest example of its class.
Aldebaran (α Tauri A)	45.1±0.1[109]	AD	Fourteenth brightest star in the night sky.
Arcturus (α Boötis)	25.4 ± 0.2[110]	AD	This is the nearest red giant to the Earth, and the fourth brightest star in the night sky.
Pollux (β Geminorum)	9.06 ± 0.03[105]	AD	The nearest giant star to the Earth.
Spica (α Virginis A)	7.47±0.54[111]		One of the nearest supernova candidates and the sixteenth-brightest star in the night sky.
Regulus (α Leonis A)	4.16 × 3.14[112]		The nearest B-type star to the Earth.
Vega (α Lyrae)	2.726±0.006 × 2.418±0.012[113]	AD	Fifth brightest star in the night sky.[82]
Altair (α Aquilae)	2.01 × 1.57[114]		Twelfth brightest star in the night sky.
Sirius (α Canis Majoris A)	1.713[115]	AD	The brightest star in the night sky.
Rigil Kentaurus (α Centauri A)	1.2175[116]	AD	Third brightest star in the night sky.
Sun	1		The largest object in the Solar System.

Further information - https://tinyurl.com/2dmm7fxb