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

  • An Alaska Airlines plane at Juneau International Airport.

    Alaska Airlines pilots plan picket over lack of compensation

    Alaska Airlines pilots have reached a breaking point in negotiations with the company, and now have plans to picket outside Ted Stevens Anchorage International Airport. The pilots plan to picket starting at 1 p.m. Monday outside the airport in Anchorage.
  • Obadiah Jenkins tries to help Daniel Hartung pull himself from Six-Mile Creek in Hope. (Photo courtesy James Bennett)

    Homer resident saves kayaker’s life on Six-Mile Creek

    Jenkins was taking a practice run through the class four rapids when a bystander filming the event, noticed another participant, Daniel Hartung, 64, of Indian Valley, flipped out of his kayak and became pinned under a log.
  • Vigor Alaska Shipyard Development director Doug Ward talks with Marine Transportation advisory board member Greg Wakefield inside the not-quite-finished Alaska Class ferry Tazlina. (Photo by Leila Kheiry/KRBD)

    Alaska class ferry Tazlina on track at Ketchikan shipyard

    The Tazlina is the first of two new Alaska Class ferries that the Ketchikan Vigor Alaska shipyard is building for the state. Its two halves are complete and welded together, and shipyard workers are busy getting interior spaces done.
  • The Matanuska sits in drydock for maintenance.

    Fall-winter-spring ferry bookings begin

    The Alaska Marine Highway is taking reservations for October through April sailings. The schedule changed so the Matanuska can get new engines.
X