True, Blue Planet Found Orbiting Nearby Star

This illustration shows HD 189733b, a huge gas giant that orbits very close to its host star HD 189733

This illustration shows HD 189733b, a huge gas giant that orbits very close to its host star HD 189733. The planet’s atmosphere is scorching with a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in howling 7000 kilometre-per-hour winds. Credit: NASA, ESA, M. Kornmesser

Move over, Earth. There’s another blue planet in town — or at least in our corner of the Milky Way.

Astronomers using the Hubble Space Telescope deduced for the first time the atmospheric hue of a planet outside our own solar system — and it turns out to be a “deep cobalt blue.”

But the similarities between HD 189733b, as the alien world is unpoetically known, and Earth, pretty much end there: While oceans of liquid water give our world its azure tint, that’s unlikely the case with HD 189733b, which orbits a star just 63 light years away from us.

The planet in question is what’s known as a “hot Jupiter” — a term that describes both its large mass and nearness to its parent star. Nature elaborates, describing the weather on HD 189733b as extremely hot and windy, with occasional glass rain:

“Although the planet seems to be the shade of a deep ocean, it is unlikely to host liquid water. The exoplanet is a giant ball of gas, similar to Jupiter, and was previously often painted brown and red in artists’ impressions.

“The blue color may come from clouds laden with reflective particles that contain silicon — essentially raindrops of molten glass. Evidence for this idea dates to 2007, when Hubble observed the planet passing in front of its star. Light from the star seemed to be passing through a haze of particles.”

But Hubble’s optical resolution isn’t good enough to actually “see” the planet. Instead, astronomers analyzed spectroscopically the light from the parent star and the planet together (during an eclipse from our vantage point), then measured it again when the planet was behind the star. The observation from the star minus the planet was less blue, indicating that is the color of the planet itself. According to Nature:

“During the eclipse, the amount of observed blue light decreased, whereas other colours remained unaffected. This indicated that the light reflected by the planet’s atmosphere, blocked by the star in the eclipse, is blue. …

” ‘This is the first time this has been done for optical wavelengths,’ said Alan Boss, an astrophysicist at the Carnegie Institution for Science in Washington DC. ‘It’s a technical tour de force.’ The amount of visible light bouncing off a planet is typically small compared to light fluctuations in a star, making planets difficult to distinguish. Fortunately, HD 189733 b is large relative to other exoplanets — and well illuminated.”

Copyright 2013 NPR. To see more, visit http://www.npr.org/.
Read original article
True, Blue Planet Found Orbiting Nearby Star

Recent headlines

  • Arctic Chinook exercise concludes

    Coast Guard wraps up Arctic exercises

    The series of simulated drills was known as the Arctic Chinook exercise and wrapped Thursday morning in Kotzebue, according to a Coast Guard press release.
  • Bacteria that causes botulism.

    Science and cooking collide to fight botulism

    Scientists are trying to learn how to prevent botulism in seal oil, a main ingredient in many traditional Alaska Native foods.
  • Earthquake Simulator

    Earthquake simulator will shake up Juneau

    Alaska's earthquake simulator will visit Wednesday, Aug. 31, to Thursday, Sept. 1, in downtown Juneau giving residents some emergency preparedness practice at an event that promises to shake, rattle and roll.
  • Dan DeBartolo is one of four candidates running for the Juneau School Board. (Courtesy of Dan DeBartolo)

    School board candidate juggles race and Facebook

    The creator of the Facebook page the Juneau Community Collective is running for public office and that created a problem. He had to figure out how to continue moderating political comments on the page without falling into a conflict of interest.

Comments

Playing Now: