The Pistol Star is a blue hypergiant star; one of the most luminous known in the Milky Way. It is one of many massive young stars in the Quintuplet cluster in the Galactic Center region. The star owes its name to the shape of the Pistol Nebula, which it illuminates. It is located approximately 25,000 light years from Earth in the direction of Sagittarius. It would be visible to the naked eye as a fourth magnitude star if it were not for the interstellar dust that completely hides it from view in visible light.

The Pistol Star, also known as V4647 Sagittarii, is a blue hypergiant star located about 25,000 light years from Earth in the constellation Sagittarius. It is a candidate luminous blue variable (cLBV) and one of the most luminous stars known.



The Pistol Star is the central star in the Pistol Nebula and It is a member of the Quintuplet Cluster and, like many other extremely massive and luminous stars in the cluster, it cannot be seen visually because it is obscured by the dust in the region of the Milky Way’s core. Without the interstellar dust and the surrounding nebulosity, the Pistol Star would be visible to the naked eye, shining at 4th magnitude from a distance of 25,000 light years.

The star’s exact age is unknown, but estimated at 4 to 10 million years. The star will likely end its life in a supernova or hypernova explosion in the next 1 to 3 million years.

Early observations indicated that it was the single most luminous star known, with an estimated luminosity almost 10 million times solar, but later studies reduced the estimate to about a third of the luminosity of Eta Carinae. The Pistol Star’s surface temperature is 11,800 K. Its absolute bolometric magnitude is -10.75.



The Pistol Star was discovered using the Hubble Space Telescope in the early 1990s by Don Figer, an astronomer at UCLA.

The star is thought to have ejected almost 10 solar masses of material in giant outbursts perhaps 4,000 to 6,000 years ago (as observed from Earth). Its stellar wind is over 10 billion times stronger than the Sun's. Its exact age and future are not known, but it is expected to end in a brilliant supernova or hypernova in 1 to 3 million years. The mass is equally uncertain, thought to have been over 100 times the Sun when initially formed but now considerably less due to extreme mass loss. Modelling the star itself to match its spectrum gives a mass of 27.5 M☉, while matching its current properties to an evolutionary model gives a much higher mass (86–92 M☉).



Later studies have reduced its estimated luminosity making it a candidate luminous blue variable about one-third as luminous as the binary star system Eta Carinae.[9] Even so, it radiates about as much energy in 20 seconds as the Sun does in a year.

A close point source has been discovered hidden in the surrounding nebulosity, but there has been no confirmation of this being a star or whether it is physically associated

The Pistol Star is believed to have shed almost 10 solar masses of material in huge outbursts between 4,000 and 6,000 years ago. When the star formed, it likely had a mass more than 100 times solar, but now has a lot less as a result of ejecting an extreme amount of material.

The star’s current mass is uncertain but, based on its spectrum, it is estimated to be 27.5 solar masses. The star’s radius is 306 times solar and its stellar wind is more than 10 billion times stronger than our Sun’s. The star radiates the same amount of energy in 20 seconds as our Sun does in a year.

The Pistol Star was discovered by Don Figer, an astronomer at UCLA, using the Hubble Space Telescope in the 1990s. At the time of discovery, the Pistol Star was suspected to have been the most massive star known