HD 209458 b facts for kids
HD 209458 b is a fascinating exoplanet. An exoplanet is a planet that orbits a star outside our own Solar System. This giant planet goes around a star called HD 209458. It is found in the constellation known as Pegasus. A constellation is a group of stars that form a pattern in the night sky.
HD 209458 b is very far away from us. It is about 159 light-years from Earth. A light-year is the distance light travels in one year, which is a very long way! This planet was first discovered in 1999.
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What is HD 209458 b like?
HD 209458 b is a very hot and large planet. It is much bigger than Earth. Its mass is about 220 times the mass of our planet. Scientists think it is a gas giant, similar to Jupiter in our Solar System.
A Hot Jupiter
Scientists call HD 209458 b a "Hot Jupiter." This is because it is a large gas giant, like Jupiter, but it orbits very close to its star. Because it is so close to its star, it gets extremely hot. The estimated surface temperature of HD 209458 b is around 1,000 °C (about 1,800 °F). That's hot enough to melt many metals!
A Short Year
Because HD 209458 b orbits so close to its star, it completes one trip around the star very quickly. A year on HD 209458 b is only about 3.5 Earth days long. Imagine having a birthday every few days!
How do we study HD 209458 b?
Scientists use special methods to learn about exoplanets like HD 209458 b.
Transiting Exoplanet
HD 209458 b is known as a "transiting exoplanet." This means that from Earth, we can see it pass directly in front of its star. When the planet passes in front of the star, it blocks a tiny bit of the star's light. Scientists can measure this dip in brightness to learn about the planet's size and orbit.
Radial Velocity Method
Scientists also detected HD 209458 b using the "radial velocity" method. This method looks for tiny wobbles in a star's movement. A planet's gravity can pull on its star, causing the star to wobble slightly. By measuring this wobble, scientists can figure out the planet's mass and how far away it is from its star.
Images for kids
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An artist's impression of HD 209458 b
See also
In Spanish: HD 209458 b para niños
