UY Scuti is a red supergiant (RSG) or red hypergiant star. It is a pulsating variable star in the constellation Scutum and one of the largest known stars in the Milky Way Galaxy. It is also one of the most luminous and well-known of its kind.
The star has an estimated median radius of 909 times that of the Sun, or a diameter of 1.26 trillion m (2 billion mi; 8.45 AU); thus a volume 750 million times that of the Sun.
It is at a distance of about 1,800 parsecs (5,870 light years) from Earth. If placed at the center of the Solar system, its photosphere would engulf the inner planets of the Solar System (Mercury, Venus, Earth and Mars), and would engulf all asteroids as well. Jupiter, Saturn, Uranus and Neptune would not be engulfed.