List of largest stars

Not to be confused with List of most massive stars.

Relative sizes of the planets in the Solar System and some of the largest stars:

1. Mercury < Mars < Venus < Earth
2. Earth < Neptune < Uranus < Saturn < Jupiter
3. Jupiter < Proxima Centauri < Sun < Sirius
4. Sirius < Pollux < Arcturus < Aldebaran
5. Aldebaran < Rigel < Antares < Betelgeuse
6. Betelgeuse < VY Canis Majoris < NML Cygni < UY Scuti

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; 432,288 mi).

Caveats

UY Scuti as seen in visible light.

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 50 of them are larger than the 700 R_☉ (490,000,000 km; 3.3 AU; 300,000,000 mi) cutoff point of this table, with the largest at 1,200–1,300.

List

This list is incomplete; you can help by expanding it.

List of the largest stars

Star	Solar radii (Sun = 1)	Notes
UY Scuti	1,708 ± 192	Margin of error in size determination: ± 192 solar radii. At its smallest, its size would be similar to that of V354 Cephei (see below).
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.
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.
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.
V354 Cephei	1,520
KY Cygni	1,430–2,850	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 but its value is not known. The larger value is consistent when taken using a higher luminosity value.
VY Canis Majoris	1,420 ± 120	Humphreys et al originally estimated the radius of VY CMa to be at 1,800–2,100 solar radii; a size so large that places it outside the bounds of stellar evolutionary theory. The quoted size is based on an improved measurement by Wittowski et al. Another study by Massey, Levesque, and Plez concludes that the star has a radius around 600 solar radii.
AH Scorpii	1,411 ± 124	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 is also variable.
VX Sagittarii	1,350–1,940	VX Sgr is a pulsating variable with a large visual range and varies significantly in size.
HR 5171 A	1,315 ± 260	Also known as V766 Cen A. V766 Centauri is a highly distorted star in a close binary system, losing mass to the secondary. According to Chesneau et al; it may be the largest star of its type (yellow hypergiant), but may be of early K-type class.
SMC 18136	1,310
Mu Cephei	1,260	Also known as Herschel's "Garnet Star".
BI Cygni	1,240
HV 11423	1,060–1,220
IRC-10414	1,200	IRC-10414 is a red supergiant companion to WR 114 (a Wolf-Rayet star).
PZ Cassiopeiae	1,190–1,940	PZ Cas is located in a region with heavy dust extinction. The upper estimate is due to an unusual K band measurement and thought to be an artifact of a reddening correction error. The lower estimate is consistent with other stars in the same survey and with theoretical models. In another opinion (such as Kusuno and Oyama) say that the star has a radius around between 1,260–1,340 solar radii.
NML Cygni	1,183	NML Cyg is a semiregular variable star surrounded by a circumstellar nebula and is heavily obscured by dust extinction.
EV Carinae	1,168
RT Carinae	1,090
V396 Centauri	1,070
CK Carinae	1,060
VV Cephei A	1,050	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. Analysis of its orbit places a firm upper limit on the size at 1,900 solar radii. Older estimates have given much larger sizes.
V602 Carinae	1,050
KW Sagittarii	1,009 ± 142
NR Vulpeculae	980
DU Crucis	979
HV 2112	972
GCIRS 7	960 ± 92	GCIRS 7 is marginally resolved at H band. We detect a significant circumstellar contribution at K band. The star and its environment are variable in size.
S Cassiopeiae	930	The largest S-type star existent in Milky Way.
IX Carinae	920
Betelgeuse	887 ± 203	Also known as Alpha Orionis. Ninth brightest star in the night sky. The angular diameter of Betelgeuse is only exceeded by R Doradus and the Sun.
Antares A	883
BC Cygni	856–1,553
V384 Puppis	850
BO Carinae	790
R Cancri	780
S Persei	780–1,230	In the Perseus Double Cluster.
SU Persei	780	In the Perseus Double Cluster
HIP 52329	780
V355 Cephei	770
V915 Scorpii	760
GP Cassiopeiae	755
RS Persei	740–800	In the Perseus Double Cluster.
V648 Cassiopeiae	710
V382 Carinae	700	Yellow hypergiant, one of the rarest types of star.
CW Leonis	700
V528 Carinae	700

The following well-known stars are listed for the purpose of comparison.

Star name	Solar radii (Sun = 1)	Notes
V509 Cassiopeiae A	650 ± 250	Yellow hypergiant, one of the rarest types of a star.
Rho Cassiopeiae	450 ± 50	Yellow hypergiant, one of the rarest types of a star.
Eta Carinae A	430 ± 370	Also known as Tseen She. Previously thought to be the most massive single star, but in 2005 it was realized to be a binary system. Its size is poorly defined.
R Leporis	400 ± 90	Also known as Hind's "Crimson Star". One of the largest carbon stars existent in the Milky Way.
La Superba	390	Also known as Y Canum Venaticorum. Currently one of the coolest and reddest stars.
V838 Monocerotis	380 ± 90	Once topped to the list as one of the largest stars. Lane et al originally estimated the radius of V838 Mon to be at 1,570 ± 400 solar radii.
S Doradus	100–380	Prototype S Doradus variable.
R Doradus	370 ± 50	Star with the second largest apparent size after the Sun.
Mira A	367 ± 35	Also known as Omicron Ceti. Prototype Mira variable.
The Pistol Star	306	Blue hypergiant, currently among the most massive and luminous stars.
Rasalgethi A	264–303	Also known as Alpha Herculis.
Deneb A	220 ± 17	Also known as Alpha Cygni. 19th brightest star in the night sky.
Peony Nebula Star	92	Candidate for most luminous star in the Milky Way.
Rigel A	78.9 ± 7.4	Also known as Beta Orionis. Seventh brightest star in the night sky.
Canopus	71 ± 7	Also known as Alpha Carinae. Second brightest star in the night sky.
Aldebaran A	44.2 ± 0.9	Also known as Alpha Tauri.
R136a1	35.4	Also on the list as the most massive and luminous star.
HDE 226868	20–22	The supergiant companion of black hole Cygnus X-1. The black hole is 500,000 times smaller than the star.
Sun	1	The largest object in the solar system. Reported for reference

See also

• Constellation
• Lists of stars
• List of most massive stars
• List of most luminous stars
• List of hottest stars
• List of coolest stars
• List of most massive black holes
• List of largest nebulae
• List of largest galaxies
• List of largest cosmic structures
• List of largest exoplanets
• List of star extremes

External links

• Giant Stars An interactive website comparing the Earth and the Sun to some of the largest stars
• BBC News Three largest stars identified
• Universe Today What is the Biggest Star in the Universe?