Pistol Star
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Sagittarius |
| Right ascension | 17h 46m 15.3s |
| Declination | -28° 50′ 04″ |
| Apparent magnitude (V) | invisible (4) |
| Details | |
| Mass | 150 M☉ |
| Radius | 300-340 R☉ |
| Luminosity | > 106 L☉ |
| Temperature | 14-21,000 K |
| Metallicity | ? |
| Rotation | ? |
| Age | 2 × 106 years |
The Pistol Star is one of the most luminous known stars in the Milky Way Galaxy. Early reports suggested that it might be the most extreme known star, producing almost 10 million times as much power as the Sun. Later studies, however, have reduced this number to roughly 1.7 million, making it one-third as luminous as the binary star system Eta Carinae[1]. The Pistol Star radiates about as much energy in 20 seconds as the Sun does in a year. Objects in this class have 80 to 150 times the mass of the Sun and "lifetimes" of about 3 million years. Unlike ordinary stars, they are strongly affected by outward pressure of the light that they emit.
This object owes its name to the shape of the Pistol Nebula which it illuminates. It is located near the center of our Galaxy, approximately 25,000 light years from Earth in the direction of Sagittarius. The Pistol Star would be visible to the naked eye as a fourth magnitude star, if it were not for the interstellar dust clouds hiding it from view; instead it was discovered by the Hubble Space Telescope in the early 1990s using infrared wavelengths that penetrate the dust. The Pistol Star is thought to have ejected almost 10 solar masses of material in giant outbursts perhaps 4000 to 6000 years ago. Its stellar wind is 10 billion times stronger than the Sun's. Its exact age and future cannot be determined for certain, but it is expected to end in a brilliant supernova or hypernova in 1 to 3 million years. Some astronomers conjecture that its large mass may be related to its location near the galactic center, since the star formation process there may favor massive objects.
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[edit] Luminous Stars
In addition to the Pistol Star, several other objects have been cited as "most luminous star" in recent years. Almost all of them have been demoted by later, improved studies. The most famous case of this demotion is that of Eta Carinae, which is now a confirmed binary star system composed of at least two stars. Our Galaxy most likely has 10 to 100 stars that surpass Eta Carinae, and they are probably detectable in infrared light; but their visible light is hidden by interstellar dust, and practical difficulties obstruct astronomers from identifying them.
[edit] See also
[edit] References
- ^ Najarro, F. (2005). "The Fate of the Most Massive Stars". ASP Conference 332: 58-68.
