The Evaporating Planet

(I think this one qualifies as a "cool science story of the day!")


Too Close For Comfort: Hubble Discovers An Evaporating Planet

For the first time, astronomers using NASA's Hubble Space Telescope have observed the atmosphere of an extrasolar planet evaporating off into space. Much of the planet may eventually disappear, leaving only a dense core. The planet is a type of extrasolar planet known as a "hot Jupiter." These giant gaseous planets orbit their parent stars very closely, drawn to them like moths to a flame.

The scorched planet, called HD 209458b, orbits only 4 million miles (7 million kilometers) from its yellow, Sun-like star. The Hubble observations reveal a hot and puffed up evaporating hydrogen atmosphere surrounding the planet. This huge envelope of hydrogen resembles a comet with a tail trailing behind the planet. The planet circles the parent star in a tight, 3.5-day orbit. Earth also has an extended atmosphere of escaping hydrogen gas, but the loss rate is much lower.

www.sciencedaily.com...

I think this one qualifies as a "cool science story of the day!") Posted by Byrd

I would agree. I think it would be really cool (guess if I had a wish for where a live transmitting space probe could be sent to send back video feed) if we had a space probe sending back close up pics of this.

And 9 years later, another planet (again first , according to article) with evaporating atmosphere due to solar flare from sun.

Astronomers making use of the Hubble Space Telescope have been able to make measurements of changes in a distant exoplanet’s atmosphere for the first time, according to a report from NASA. After monitoring a powerful solar flare from the planet’s parent star, astronomers were able to detect noticeable changes in the planet’s atmosphere in response.

The planet in question is identified as HD 189733b, and it is in that class of exoplanets which pass directy in front of their parent stars as viewed from Earth. Such a pass in front of the star is referred to as a “transit”. The light traveling to Earth during such a transit can be examined to uncover details about the orbiting exoplanet. “We hadn’t just confirmed that some planets’ atmosphere evaporate, we had watched the physical conditions in the evaporating atmosphere vary over time,” study leader Alain Lecavelier des Etangs, of the National Center for Scientific Research in France, said in a statement. “Nobody had done that before.”

Astronomers had previously determined that HD 189733b was a “hot Jupiter”, that is, a very large planet that orbits very close to its parent star. HD 189733b is about 14 percent more massive than Jupiter, and orbits only 3 million miles from its parent star. (For comparison, the innermost planet in our own solar system is tiny Mercury, which orbits over 28 million miles from the Sun, and our largest planets orbit in the farthest portion of our solar system.) This close orbit means that HD 189733b is subject to high temperatures, with an estimated internal atmospheric temperature of over 1900 degrees Fahrenheit.

source

In other words, that star is killing the planet...

ps. Sorry to bump ol' thread - it seemed appropriate in this case...