Osiris, also known as HD 209458b, is an extra solar planet with some intriguing characteristics. It is known for being the first exoplanet outside our solar system with oxygen and carbon detected in its atmosphere, though there’s a catch. The oxygen and carbon observed on Osiris is evaporating at such a rate that it created a new classification of extra solar planets called “chthonian” planets, or rather dead cores of completely evaporated gas giants. Just imagine our own Jupiter, stripped naked of its easily identifiable gas (how ghastly) features.
HD 209458b is a popular planet due to its list of notable firsts. It is the first planet discovered outside of our solar system that transits its sun. It’s also the first extrasolar planet discovered with an atmosphere, and the first known for having an evaporating hydrogen atmosphere, and now we can add oxygen and carbon to the list.
This so called “blow-off” effect observed using the Hubble Telescope has never been seen before. The phenomenon is far more efficient than evaporation that occurs on Earth, where on Osiris, gasses are literally ripped away at or above a speed of 35,000 km/hour.
This effect is so unique that astronomers propose the “chthonian planet,” which just so happens to reference the Greek God Khton, a deity from the hot infernal underworld. Pretty neat, huh.
Because of this astounding plethora of unique characteristics, the planet has been rightfully dubbed “Osiris” after the Egyptian god who was killed by Set and denied a resurrection.
Osiris orbits its star a mere 7 million kilometers away resulting in a scorched surface that reaches temperatures of up to 1000 degrees Celsius. So even though there’s oxygen in its atmosphere, a clear indicator of potential life, it is highly unlikely that Osiris hosts life, earth-like anyway, though I suppose anything’s possible. There could just be a bunch of lava people there worshipping Egyptian gods, who knows?
This unusually intense evaporation process may serve as validation for certain theories regarding the formation of planets within our own solar system, including Venus, Earth, and Mars, which during the early stages of their formation may have completely lost their original atmospheres before their current ones were affected by extraterrestrial impacts from asteroids and comics.