51 Pegasi b facts for kids
51 Pegasi b, also known as Bellerophon or 51 Peg b, is a super special planet. It was the very first exoplanet (a planet outside our Solar System) ever found orbiting a main-sequence star, which is a star like our Sun. This star is called 51 Pegasi.
Two scientists, Michel Mayor and Didier Queloz, announced they had discovered it on October 6, 1995. This planet is about 50 light-years away from us. A light-year is how far light travels in one year, so 50 light-years is an incredibly long distance! You can find this star system in the direction of the constellation called Pegasus, which looks like a winged horse in the night sky.
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What is 51 Pegasi b?
51 Pegasi b is a type of exoplanet known as a "Hot Jupiter". This means it's a giant gas planet, much like Jupiter in our own Solar System. However, it's called "Hot" because it orbits incredibly close to its star.
A Very Close Orbit
Because 51 Pegasi b is so close to its star, it's super hot! Its surface temperature is estimated to be around 1,000 degrees Celsius (about 1,800 degrees Fahrenheit). Imagine how hot that is! It completes one full trip around its star in just about 4.2 Earth days. That's a very fast year compared to Earth's 365 days!
How Big is it?
Even though it's a gas giant like Jupiter, 51 Pegasi b is a bit different. It's thought to be about half the mass of Jupiter. But because it's so hot, its atmosphere might be puffed up, making it appear larger than Jupiter in size. Scientists are still learning more about its exact size and what its atmosphere is made of.
How Was it Found?
Scientists Michel Mayor and Didier Queloz used a method called the "radial velocity" method to find 51 Pegasi b.
The Wobble Method
This method looks for tiny wobbles in a star's movement. When a planet orbits a star, its gravity pulls on the star a little bit. This pull makes the star wobble back and forth. Even though the wobble is tiny, scientists can measure it using special tools. By measuring how the star wobbles, they can figure out if there's a planet orbiting it and even estimate its size and how close it is to the star.
A Big Discovery
Finding 51 Pegasi b was a huge moment in astronomy. Before this, we didn't know for sure if planets existed outside our Solar System, especially orbiting stars like our Sun. This discovery opened the door to finding thousands more exoplanets and helped us understand that planets are common in the universe.
Where is 51 Pegasi?
The star 51 Pegasi is located in the constellation of Pegasus. This constellation is easy to spot in the night sky during the autumn months in the Northern Hemisphere. It looks like a large square, often called the "Great Square of Pegasus."
Finding the Star
You won't be able to see 51 Pegasi b itself, even with a powerful telescope, because it's too small and too far away. But you can try to find its star, 51 Pegasi. It's a bit too dim to see with your bare eyes, but you might be able to spot it with binoculars or a small telescope if you know where to look within the Pegasus constellation.
Images for kids
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A promotional "Exoplanet Travel Bureau" poster from NASA
See also
In Spanish: Dimidio para niños
