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List of largest stars

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Not to be confused with List of most massive stars.
UY Scuti as seen in visible light.

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 (approximately 695,500 kilometers, or 432,450 miles).

The exact order of this list is not complete, nor is it perfectly defined:

  • There are sometimes high uncertainties in derived values and sizes;
  • The distances to most of these stars are uncertain to differing degrees and this uncertainty affects the size measurements;
  • All the stars in this list have extended atmospheres, many are embedded in mostly opaque dust shells or disks, and most pulsate, such that their radii are not well defined;
  • There are theoretical reasons for expecting that no stars in the Milky Way are larger than approximately 1,500 times the Sun, based on evolutionary models and the Hayashi instability zone. The exact limit depends on the metallicity of the star, so for example supergiants in the Magellanic Clouds have slightly different limiting temperature and luminosity. Stars exceeding the limit have been seen to undergo large eruptions and to change their spectral type over just a few months;
  • A survey of the Magellanic Clouds has catalogued most of the red supergiants and 44 of them are larger than the 700 solar radii cutoff point of this table, with the largest at 1,200–1,300.[1]


List of the largest stars
Star Solar radii
(Sun = 1)
Notes Ref.
UY Scuti 1,708 Margin of error in size determination: ± 192 solar radii. At its smallest, its size would be similar to that of VX Sagittarii (see below). [2]
NML Cygni 1,642–2,775 NML Cyg is a semiregular variable star surrounded by a circumstellar nebula and is heavily obscured by dust extinction. [3]
WOH G64 1,540–1,730 This would be the largest star in the LMC, but is unusual in position and motion and might still be a foreground halo giant. [4][5]
RW Cephei 1,535 RW Cep is variable both in brightness (by at least a factor of 3) and spectral type (observed from G8 to M), thus probably also in diameter. Because the spectral type and temperature at maximum luminosity are not known, the quoted size is just an estimate. [6][7]
Westerlund 1-26 1,530 Very uncertain parameters for an unusual star with strong radio emission. The spectrum is variable but apparently the luminosity is not. [8]
VX Sagittarii 1,520 VX Sgr is a pulsating variable with a large visual range and varies significantly in size. [9]
VV Cephei A 1,050–1,900 VV Cep A is a highly distorted star in a binary system, losing mass to its B-type companion VV Cephei B for at least part of its orbit.
VY Canis Majoris 1,420 Previously thought to be a star so large that it contradicted stellar evolutionary theory, a newly improved measurement has brought it down to size. Margin of possible error: ± 120 solar radii. [10][11]
KY Cygni 1,420 KY Cygni is located in a region with heavy dust extinction, thus making it hard to determine its size. The quoted size is the value consistent with stellar evolutionary models, the true range may be larger. [12]
AH Scorpii 1,411 AH Sco is 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. [2]
HR 5171 A 1,316 HR 5171 A is a highly distorted star in a close binary system, losing mass to the secondary. [13]
SMC 18136 1,310 [1]
PZ Cassiopeiae 1,260–1,340 [14]
KW Sagittarii 1,235 [2][12]
IRC-10414 1,200 [15]
EV Carinae 1,168 [16]
BC Cygni 1,140 [12]
RT Carinae 1,090 [12]
BI Cygni 1,078 [9][12]
Betelgeuse (Alpha Orionis) 950-1,200 Ninth brightest star in the night sky. [17]
V396 Centauri 1,070 [12]
CK Carinae 1,060 [12]
V602 Carinae 1,050 [18]
Mu Cephei (Herschel's "Garnet Star") 1,035 [12][19]
S Persei 1,005 In the Perseus Double Cluster. [12]
RS Persei 1,000 In the Perseus Double Cluster. [12]
NR Vulpeculae 980 [12]
RW Cygni 980 [12]
GCIRS 7 960 [20]
Antares A (Alpha Scorpii A) 883
Theta Muscae 878
V1749 Cygni 830 [12]
IX Carinae 790 [12]
SU Persei 780 In the Perseus Double Cluster [12]
TV Geminorum 770 [12]
T Cephei 742
V382 Carinae 700 Yellow hypergiant, one of the rarest types of star.
The following well-known stars are listed for the purpose of comparison.
Star name Solar radii
(Sun = 1)
Notes Ref.
V509 Cassiopeiae 650 Yellow hypergiant, one of the rarest types of a star.
TZ Cassiopeiae 645
CE Tauri ("Ruby Star") 601 Can be occulted by the Moon, allowing accurate determination of its apparent diameter.
V355 Cephei 535 [9][12]
R Leporis ("Hind's Crimson Star") 500 One of the largest carbon stars existent in the Milky Way.
Alpha Herculis (Ras Algethi) 460
Rho Cassiopeiae 450 A yellow hypergiant, one of the rarest types of a star.
Mira A (Omicron Ceti) 400 Prototype Mira variable
V838 Monocerotis 380 Once topped to the list as one of the largest stars, after experiencing a nova outburst it gradually decreased in size.
R Doradus 370 Star with the second largest apparent size after the Sun.
The Pistol Star 306 Blue hypergiant, currently among the most massive and luminous stars.
Eta Carinae A (Tseen She) 240 Previously thought to be the most massive single star, but in 2005 it was realized to be a binary system
S Doradus 240 Prototype S Doradus variable
La Superba (Y Canum Venaticorum) 215 Currently one of the coolest and reddest stars.
Deneb (Alpha Cygni) 203 19th brightest star in the night sky.
Peony Nebula Star 100 Candidate for most luminous star in the Milky Way.
Rigel A (Beta Orionis A) 78 Seventh brightest star in the night sky.
Canopus (Alpha Carinae) 65 Second brightest star in the night sky.
Aldebaran (Alpha Tauri) 44.2 [21]
R136a1 28.8 Also on the list as the most massive and luminous star.
HDE226868 21 The supergiant companion of black hole Cygnus X-1. The black hole is 500,000 times smaller than the star.
VV Cephei B 10 The B-type main sequence companion of VV Cephei A.

See also


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  2. ^ a b c Arroyo-Torres, B.; Wittkowski, M.; Marcaide, J. M.; Hauschildt, P. H. (2013). "The atmospheric structure and fundamental parameters of the red supergiants AH Scorpii, UY Scuti, and KW Sagittarii". Astronomy & Astrophysics 554: A76. Bibcode:2013A&A...554A..76A. doi:10.1051/0004-6361/201220920. 
  3. ^ Zhang, B.; Reid, M. J.; Menten, K. M.; Zheng, X. W.; Brunthaler, A. (2012). "The distance and size of the red hypergiant NML Cygni from VLBA and VLA astrometry". Astronomy & Astrophysics 544: A42. arXiv:1207.1850. Bibcode:2012A&A...544A..42Z. doi:10.1051/0004-6361/201219587. 
  4. ^ Emily M. Levesque, Philip Massey, Bertrand Plez, and Knut A. G. Olsen (June 2009). "The Physical Properties of the Red Supergiant WOH G64: The Largest Star Known?". Astronomical Journal 137 (6): 4744. arXiv:0903.2260. Bibcode:2009AJ....137.4744L. doi:10.1088/0004-6256/137/6/4744. 
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  6. ^ Humphreys, R. M. (1978). "Studies of luminous stars in nearby galaxies. I. Supergiants and O stars in the Milky Way". The Astrophysical Journal Supplement Series 38: 309. Bibcode:1978ApJS...38..309H. doi:10.1086/190559. 
  7. ^ Davies, Ben; Kudritzki, Rolf-Peter; Figer, Donald F. (2010). "The potential of red supergiants as extragalactic abundance probes at low spectral resolution". Monthly Notices of the Royal Astronomical Society 407 (2): 1203. Bibcode:2010MNRAS.407.1203D. doi:10.1111/j.1365-2966.2010.16965.x. 
  8. ^ Wright, N. J.; Wesson, R.; Drew, J. E.; Barentsen, G.; Barlow, M. J.; Walsh, J. R.; Zijlstra, A.; Drake, J. J.; Eisloffel, J.; Farnhill, H. J. (16 October 2013). "The ionized nebula surrounding the red supergiant W26 in Westerlund 1". Monthly Notices of the Royal Astronomical Society: Letters 437 (1): L1–L5. arXiv:1309.4086. Bibcode:2014MNRAS.437L...1W. doi:10.1093/mnrasl/slt127. 
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  11. ^ Choi, Yoon Kyung; Hirota, Tomoya; Honma, Mareki; Kobayashi, Hideyuki; Bushimata, Takeshi; Imai, Hiroshi; Iwadate, Kenzaburo; Jike, Takaaki; Kameno, Seiji; Kameya, Osamu; Kamohara, Ryuichi; Kan-Ya, Yukitoshi; Kawaguchi, Noriyuki; Kijima, Masachika; Kim, Mi Kyoung; Kuji, Seisuke; Kurayama, Tomoharu; Manabe, Seiji; Maruyama, Kenta; Matsui, Makoto; Matsumoto, Naoko; Miyaji, Takeshi; Nagayama, Takumi; Nakagawa, Akiharu; Nakamura, Kayoko; Oh, Chung Sik; Omodaka, Toshihiro; Oyama, Tomoaki; Sakai, Satoshi; et al. (2008). "Distance to VY CMa with VERA". Publications of the Astronomical Society of Japan (Publications Astronomical Society of Japan) 60 (5): 1007. arXiv:0808.0641. Bibcode:2008PASJ...60.1007C. doi:10.1093/pasj/60.5.1007. 
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