Exoplanet Hotter than a Star


Photo courtesy of sci-news.com

Astronomers have discovered the hottest-known exoplanet on June 5. The temperatures on the surface of this planet are as hot as most stars.

An exoplanet is a planet that exists outside of our Solar System. This planet, given the name KELT-9b, is a gas giant, much like Jupiter.

KELT-9b’s orbit is so small that one revolution is equivalent to 1.5 days on Earth. This has caused the planet to have one side constantly facing the star, much like how the Moon orbits around the Earth.

Because of this, temperatures on the sunny side of KELT-9b are extremely hot and can reach up to 7800 ˚F. That is hotter than most dwarf stars and is only 2200 ˚F cooler than the Sun. As a result, some of our most common compounds, such as water and carbon dioxide, can likely not exist on the surface of the planet.

Since KELT-9, the planet’s star, is much bigger and hotter than the sun, it has caused KELT-9b to become denser and “blow up.” For comparison, KELT-9b is 2.8 times more massive than Jupiter, but is also twice as dense.

However, this gaseous superstar, or rather super-planet, is in danger. “KELT-9 radiates so much ultraviolet radiation that it may completely evaporate the planet,” said Keivan Stassun, a professor of physics and astronomy at Vanderbilt University and the co-leader of the study that discovered KELT-9b. “Or, if gas giant planets like KELT-9b possess solid rocky cores as some theories suggest, the planet may be boiled down to a barren rock, like Mercury.” NASA’s Hubble telescope may be able to detect if KELT-9b is evaporating by detecting a comet-like trail.

By: Catherine Petretti’18, Guest Writer

Categories: Features