VY CMa is a single star with a large infrared (IR) excess, making it one of the brightest objects in the sky at wavelengths of between 5 and 20 microns (µm) and indicating a dust shell or disk heated by the star.[14][15]  It is about 17±8 times the mass of the Sun (M☉). It is also surrounded by a complex asymmetric circumstellar envelope (CSE) 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 Sharpless 310 (Sh2-310), one of the largest star-forming HII regions with a diameter of 480 arcminutes (') or 681ly (209pc).[16][17]

Since VY CMa has no companion star, its mass cannot be measured directly through gravitational interactions. Comparison of the effective temperature and bolometric luminosity of VY CMa compared to evolutionary tracks for massive stars suggest an initial mass of 25±10M☉ for a rotating star with a current mass of 15M☉, or 32M☉ for a non-rotating star with a current mass of 19M☉,[3] and an age of 8.2 million years (MYr).[11] Older studies have found much higher initial masses (thus also higher current masses) or a progenitor mass of 40 - 60M☉ based on old luminosity estimates.[14][45]