Size comparison: Betelgeuse vs UY Scuti

Size comparison between two red super giants, Betelgeuse and UY Scuti.

UY Scuti is a star in the constellation Scutum. It is the largest known star in terms of radius. UY Scuti is in fact 1,708 times larger than the sun. Its distance from the earth is 9,500 light years. Its photosphere could encompass the orbit of Jupiter. UY Scuti has started consuming its helium and continues to fuse its hydrogen. Its location deep in the Milky Way suggests that the red super giant is rich in metal.

Object	Betelgeuse	UY Scuti
Type	Star, red supergiant	Star, red supergiant
Diameter	1,235,310,708 km	2,376,511,200 km
Mean radius	617,655,354 km	1,188,255,600 km
Mass	2.29 × 1031 kg	1.7 × 1031 kg
Surface gravity	-0.001 m/s²	-0.005 m/s²
Circumference	1.2 billion km	7.46 billion km
Surface area	1.5 × 1018 km2	1.77 × 1019 km2
Volume	9.87 × 1026 km3	7 × 1027 km3
Atmosphere composition	hydrogen, helium	hydrogen, helium
Crust composition	hydrogen, helium	hydrogen, helium
Sun distance	724 light years	9,500 light years
Luminosity	5.73 × 1031 W	1.3 × 1032 W
Photosphere temperature	3,590 K	3,365 K
Spectral classification	M1–M2 Ia–ab	M2-M4Ia-Iab
Right ascension	05h 55m 10.29s	18h 27m 36.53s
Declination	+07° 24′ 25.3″	−12° 27′ 58.866″

Note: if one of the objects is not visible, it just means that it is too tiny to be displayed compared to the other one.