Stephenson 2-18 Is a Red Supergiant and the Largest star Known, With a radius of 2,150 or 2,163 solar radii. It is so large, It will engulf the orbit of Saturn and Surpass it. It is Located in the Stephenson 2 open cluster where 25 other Red Supergiants are located 20,000 Light Years away in the Constellation of Scutum.
It is The largest star known, Surpassing UY Scuti's old size, VY Canis Majoris' Old size and VV Cephei's old size. It is the Largest star since 2013, the reference of Stephenson 2-18's size was published in 2012. Back then, Westerlund 1-26 was still the largest star known,. When A new estimate came for Westerlund 1-26 Stephenson 2-18 became the largest but was unseen until 2020. Its Temperature is 3,200 Kelvin, Its Luminosity is 440,000 solar Luminosities and Its radius is an overwhelming 2,150 or 2,163 solar radii. Even though it is so large, it is Below the Limit for Star sizes.