LBV 1806−20 facts for kids
 Infrared image of Cluster 1806_20. LBV 1806−20 is the brightest star, on the left. Credit: Hubble Space Telescope |
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| Observation data Epoch J2000 Equinox J2000 |
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|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 08m 40.31s |
| Declination | −20° 24′ 41.1″ |
| Characteristics | |
| Evolutionary stage | candidate LBV |
| Spectral type | O9 - B2 |
| Apparent magnitude (J) | 13.93 |
| Apparent magnitude (H) | 10.75 |
| Apparent magnitude (K) | 8.89 |
| Astrometry | |
| Distance | 8.7k pc |
| Details | |
| Mass | 36 M☉ |
| Radius | 46-145 R☉ |
| Luminosity | ~2,000,000 L☉ |
| Temperature | 18,000–32,000 K |
| Age | 3.0 – 4.5 Myr |
| Other designations | |
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2MASS J18084031-2024411
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| Database references | |
| SIMBAD | data |
LBV 1806−20 is a very special and super bright star. It's thought to be a luminous blue variable (LBV) and probably a binary star, meaning it's two stars orbiting each other. It is located about 28,000 light-years away from the Sun. This is towards the center of our galaxy, the Milky Way.
This star is huge, with a mass about 36 times that of our Sun. It shines incredibly brightly, giving off about two million times more light than the Sun. Even though it's so bright, we can't see it with our eyes. This is because a lot of dust between us and the star blocks almost all of its visible light.
When LBV 1806−20 was first found, scientists thought it was the brightest and most massive star known. This made them rethink how giant stars form. Now, with better measurements, we know it's a bit closer. Also, since it's likely a binary star, its properties fit better with what we expect for very bright stars in our galaxy.
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Where is LBV 1806−20?
LBV 1806−20 sits right in the middle of a radio nebula called G10.0–0.3. A nebula is a giant cloud of gas and dust in space. This nebula is mostly lit up by the strong winds coming from LBV 1806−20.
This star is part of a group of stars called the 1806−20 open cluster. An open cluster is a group of stars that were born around the same time from the same giant cloud. This cluster is also part of an even bigger area called W31. W31 is one of the largest H II regions in the Milky Way. H II regions are places where new stars are forming.
The 1806−20 cluster has some very unusual stars. These include four Wolf–Rayet stars, which are very hot and massive stars. It also has several OB stars, which are also very hot and bright. Plus, it has a magnetar called SGR 1806−20. A magnetar is a type of neutron star with an extremely powerful magnetic field.
What is its light like?
Scientists study the light from LBV 1806−20 to learn about it. The type of light it gives off can change, so it's a bit hard to classify. Based on its infrared light, it seems to be between an O9 and B2 type star. These are very hot and bright stars.
The light from LBV 1806−20 shows strong signs of hydrogen and helium. It also shows signs of other elements like iron, magnesium, and sodium. These signs appear as bright lines in its spectrum, which is like a rainbow of light. The lines are wide and sometimes have strange shapes. This tells scientists about the star's strong winds.
Star's Features
Because there's so much dust between us and LBV 1806−20, most of its visible light is blocked. This means scientists have to use infrared telescopes to study it. Infrared light can pass through dust more easily than visible light.
Based on how bright it is and the type of light it gives off, scientists think it might be a luminous blue variable (LBV). LBVs are stars that change their brightness and appearance over time. However, scientists haven't seen these changes yet in LBV 1806−20. So, for now, it's still just a "candidate" LBV.
Is it a Binary Star?
Scientists believe LBV 1806−20 is actually two stars orbiting each other. This idea helps explain some confusing things about its light. For example, some of the helium lines in its light appear doubled. This suggests there are two sources of light.
Also, if it's a binary star, it helps make sense of its mass, brightness, and age estimates. Only one of the stars seems to have a strong stellar wind, which is what you'd expect from an LBV.
See also
In Spanish: LBV 1806-20 para niños
