Yellow hypergiant facts for kids
A yellow hypergiant is a truly enormous star. These stars are among the biggest and brightest in the universe. They start out weighing about 20 to 60 times more than our Sun. However, they quickly lose about half of their mass because they are very unstable.
Yellow hypergiants are incredibly bright. They shine with an amazing power, making them easy to spot even from far away. They are also very rare. Scientists have found only about 15 of them in our home galaxy, the Milky Way. Six of these rare stars are even found together in one group called a star cluster.
These stars are sometimes called 'cool hypergiants' when compared to even hotter stars. But they are also called 'warm hypergiants' when compared to cooler, red supergiant stars. Yellow hypergiants have changed a lot since they first formed. They have used up most of the hydrogen fuel in their cores.
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What Makes a Yellow Hypergiant Special?
Yellow hypergiants are unique because of their size, brightness, and how quickly they change.
Size and Mass
When a yellow hypergiant is born, it is huge. It can be 20 to 60 times heavier than our Sun. Imagine a star that big! But these stars are not stable. They often throw off a lot of their outer layers. This means they lose a lot of their original mass over time.
Brightness and Color
These stars are extremely bright. Their brightness is measured by something called 'absolute magnitude'. For yellow hypergiants, this number is around -9, which is incredibly bright. The lower the number, the brighter the star. Their color ranges from yellow-white to orange. This color tells us about their temperature.
How They Change
Yellow hypergiants are stars that have already lived through their main life stage. Most stars, like our Sun, spend a long time burning hydrogen in their center. This is called the main sequence. Yellow hypergiants have moved past this stage. They have used up most of their hydrogen fuel. This makes them expand and become very unstable.
Famous Yellow Hypergiants
Here are some well-known examples of these amazing stars:
Images for kids
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Visual light curve for ρ Cassiopeiae from 1933 to 2015
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IRAS 17163-3907 is a yellow hypergiant that clearly shows the expelled material that probably surrounds all yellow hypergiants.
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Yellow hypergiant HR 5171 A, seen as the bright yellow star at the center of the image.
See also
In Spanish: Hipergigante amarilla para niños
