The Evaporating Atmosphere of HD 189733 b

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There is a planet that is 63 light years away from our home that is bigger than Jupiter and orbits its star at a distance one-thirteenth of Earth’s orbit around the Sun. It’s reasonable to say that exoplanet HD 189733 b is a hot place, with little chance of supporting any life. But in this case, extreme life forms are not the primary interest of scientists, but rather, its atmosphere – or what’s left of it. The atmosphere of HD 189733 b is evaporating, and the star that it orbits, HD 189733, is the likely culprit behind this evaporation. However, it doesn’t appear to be the extreme heat that’s causing the evaporation.

Observers have taken an interest in HD 189733 b since it helps give astronomers clues as to how stellar weather activity functions in conditions much different from our own. Although the regular temperatures on HD 189733 b hovers around 1,000 degrees celsius, such an extreme temperature is not hot enough to affect the atmosphere. It seems that massive plumes of gas – originating from planet’s star – release ultraviolet and X-ray radiation and are the leading factors being attributed to the planet’s atmospheric evaporation. How extreme are these flares? Well, you know that our Sun causes bathes our planet in x-rays, and posing a risk of cancer –  but we survive. Now, multiply the amount that Earth experiences by three million, and that is what HD 189733 b gets.

Though HD 189733 b has been studied since its discovery in 2005, interest in it has been risen since there was a massive X-ray flare that came from HD 189733 (the star) in 2011. The scale is unmatched compared to observances in the past, and this has caused astronomers to flock to the occurrence. So, can the X-rays actually be the contender for causing the atmospheric evaporation? Quite possibly. The release of the X-ray radiation heats up the upper part of the atmosphere enough its contents start to escape the gravitational pull of HD 189733 b.

Cosmically speaking, this is a pretty quick process of evaporation, with 1,000 tons of gas being lost per second. Our planet experiences this sort event as well, but obviously it is not to the noticeable scale to that of HD 189733 b. However, if the events of HD 189733 b can be scaled and assigned to that of the Earth, then it may expose some information as to how our own Sun may influence and affect our electrical systems. Scientists want to be able to continually observe and understand how the material released from stars affect its orbiting planets, and HD 189733 b is perfect for this.

An article in Phys.Org has said that HD 189733 b could also be used to study the eventual possible outcome that it becomes a “super Earth.” It wouldn’t be the first time that a massive body like HD 189733 b becomes nothing more than a rocky planet after its atmosphere has been evaporated. Only further observations of HD 189733 b will help us to predict its fate.


This has been a guest post by author Mike Lamardo who writes articles for blog tech, science, music – all things interesting. When he’s not finding out about news stories, he works in promoting educational channels for Direct 4 TV.

Additional Sources:
Mother Nature Network

The Bunsen Burner