HD 209458b is a strange and terrible name and seems quite odd. As the name is terrible, so is the place. HD 209458b was discovered in November 1999. HD 209458b lies in the constellation of Pegasus. It is about 150 light years away from our solar system and definitely lies in our own Milky Way Galaxy. This planet is quite a hell, but it has also given new direction to astronomers in searching and studying Gas Giants. Dip in brightness of a star known as HD 209458, was caused by the transit of the planet which made the discovery of this planet possible. This extrasolar planet has turned out to be a burning hell. The radius of the orbit of this planet is about 7 million kilometers, which is about one eighth the radius of Mercury's orbit. This small distance is the reason that it takes only 3.5 Earth days to complete one rotation around its parent sun. The temperature on this planet’s surface is about more than 1000 degrees Celsius. HD 209458b is more than 200 time massive than earth. These observations indicate that this is a Gas Giant Planet like Gas Giants in our solar system.
|Image Source: spacetelescope.org|
HD 209458b was the first planet to have its orbital speed measured and not only this, but it was also the first extrasolar planet to have known composition of atmosphere. This planet has migrated a lot closer to it sun, so that its atmosphere is evaporating in space. HD 209458b is also known as Planetary Hell due to its most of the properties like temperature. Average temperate on HD 209458b is above 1000 degrees Celsius, so forget global warming this is more like Global hell. Close distance to its parent star and high temperature cause it to lose more than 500 thousand metric tons per second of air into the space. This steady stream of hydrogen, Helium and oxygen that make a huge cloud all over the planet. Its atmosphere is bleeding into the space.
The tail of gas is spiraling behind the planet over thousands of kilometers. Using Hubble, scientists have analyzed its surface and composition of its atmosphere. Hubble has detected many basic elements in its atmosphere like sodium, carbon, hydrogen and oxygen. On this planets life is impossible, but there can be many other ways of finding life around this planet. Just like Jupiter there is no solid surface on this planet. After this discovery, astronomers have discovered many hot Jupiter like planets. This planet orbits its parent star like a yo-yo. This discovery has also explained and still helping in understanding many properties of extra solar planets. This is the only Extrasolar planet discovered with the minimum distance from its parent star because more close planets can easily burn up in a short time before even getting detected.
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