page_title: VY Canis Majoris
section_title: Physical properties
hierarchical_section_title: VY Canis Majoris / Physical properties
context_page_description: VY Canis Majoris is an extreme oxygen-rich red hypergiant or red supergiant and pulsating variable star located at 1.2 kiloparsecs away from Earth in the constellation of Canis Major. It is one of the largest known stars by radius, and is also one of the most luminous and massive red supergiants, as well as one of the most luminous stars in the Milky Way.
  VY CMa is a single star with a large infrared excess, making it one of the brightest objects in the sky at wavelengths of between 5 and 20 microns and indicating a dust shell or disk heated by the star. It is about 17±8 times the mass of the Sun. It is also surrounded by a complex asymmetric circumstellar envelope caused by mass loss from the star itself. It produces strong molecular maser emission and was one of the first radio masers discovered. VY CMa is embedded within the large molecular cloud Sh2-310, one of the largest star-forming H II regions with a diameter of 480 arcminutes or 681 ly.
  The radius of VY CMa is about 1,420 times that of the Sun, which is close to the Hayashi limit and corresponds to a volume about 3 billion times bigger than the Sun.
context_section_description: A very large and luminous star, VY CMa is among the most extreme stars in the Milky Way and has an effective temperature below 4,000 K (3,730 °C; 6,740 °F).  It occupies the upper-right hand corner of the HR diagram although its exact luminosity and temperature are uncertain. Most of the properties of the star depend directly on its distance.
caption: VY Canis Majoris compared to the Sun and the Earth's orbit.