Alien Planet Kepler-7b Forecast: Partly Cloudy With A High Of 1,500 F

Kepler-7b (left), which is 1.5 times the size of Jupiter (right), is the first exoplanet to have its clouds mapped. The hot planet zips around its host star in just under 5 days. Despite its large size, it’s only half as massive as Jupiter, making it one of the “fluffiest” planets known. Credit: NASA/JPL-Caltech/MIT

Finally – a dream planet for meteorologists. Astronomers using data from NASA’s Kepler and Spitzer space telescopes have created the first cloud map ever of a planet beyond our solar system. Far away on Kepler-7b, clear skies dominate the planet’s eastern hemisphere while high clouds bedeck the west. Even I can forecast the weather working with those odds.

The Kepler spacecraft finds planets beyond our solar system by detecting changes in star brightness when a planet passes in front of a star (upper right). It surveyed over 100,000 stars simultaneously in a small section of the constellations Lyra and the Northern Cross (Cygnus) for some 4 years. Credit: NASA/ Wendy Stenzel

Kepler 7-b was one of the first five planets to be confirmed by the Kepler spacecraft. Orbiting just 5.6 million miles (9 million km) from its host star in the constellation Lyra, the planet sizzles with a surface temperature between 1,500 and 1,800 degrees F (815-980 degrees C). While that’s twice as hot as our solar system’s scorcher planet Venus, scientists were puzzled why Kepler-7b wasn’t even hotter given how close it is to its sun.

Animation showing an extrasolar planet passing in front of a star, causing its light to dim. By studying the light curve (bottom) astronomers can determine planets sizes and other details. Credit: Transits of Extrasolar Planets Network

Kepler tracked the hot world through its moon-like phases for more than three years to create a rough map that showed a bright spot in its western hemisphere. Unsure as to whether the spot originated from clouds or the glow of intense heat,  NASA swung the Spitzer Space Telescope around for a look. Even though it wasn’t designed to study exoplanets, it proved to be the perfect tool to solve the mystery of the white spot.

Spitzer studies celestial objects by the heat they radiate called infrared light. After three years of analysis, scientists determined that Kepler-7b’s temperature was too cool to be the source of the bright spot. Instead, a cloudy western hemisphere fit the data much better. Clouds are excellent reflectors of light; starlight bouncing from the planet’s cloud tops made sense.

“Kepler-7b reflects much more light than most giant planets we’ve found, which we attribute to clouds in the upper atmosphere,” said Thomas Barclay, Kepler scientist at NASA’s Ames Research Center in Moffett Field, Calif. “Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time – it has a remarkably stable climate.”

Kepler’s eye extended across 3,000 light years along one the Milky Way’s spiral arms. Credit: NASA

Sadly, Kepler is no longer operational. One of its four reaction wheels, which keep the space telescope precisely pointed on a target, failed last July. When a second one failed in May, the scope was unable to continue its mission. Kepler needs a minimum of three wheels for accurate aiming.

We can be grateful for the more than 3,500 candidate planets the probe discovered during four years of useful life. They were all found by studying dips in a star’s brightness when a planet crossed or transited in front of it, blocking out a tiny portion of the light.

Just 151 of those planets have been confirmed, but scientists expect more 90 percent to be added to the roster once all the data’s crunched. Despite its unfortunate end, Kepler’s legacy will shine for years to come.

12 Responses

  1. Edward M. Boll

    This is unconfimed at this point.But one ephemeris that I saw on the internet put the magnitude of Comet Lovejoy at 8.8 already.

    1. astrobob

      Hi Edward,
      I can confirm Lovejoy is no brighter than 10. I just saw it at ~10.5 magnitude and several recent observations by other observers put it in the 10-10.5 range. Jacob Cerny, a regular contributor of comet observations on the list, gave it 12th mag. on Oct. 1.

  2. Edward M. Boll

    I found this in the site Comet Chasing. But, they had it in position to October 14, so the 8.79 given may have been for that date. That would have been my mistake.

  3. Edward M. Boll

    I had previously predicted Lovejoy about 10.2 on the 5th. I assume that ISON and Encke are brighter than 10 now. I really want to try to see ISON with 20 power binoculars on the 16th when it is in conjunction with not only Mars, but Regulus too.

    1. astrobob

      ISON is 11 mag. right now; Encke is between 10 and 11 mag. depending on the observer. A very diffuse object still. I saw Encke 3 nights ago at mag. 10.7 in my 15-inch. Even in that scope you wouldn’t call it bright by a long stretch. Likewise ISON.

    1. astrobob

      It won’t be long. And you never know – any of those comets could experience an outburst and jump into binocular range.

  4. Edward M. Boll

    I rechecked the ephemeris of ISON and was satisfied with what I found. At magnitude 11, it has brightened about 8 magnitudes since discovery. It is now a little more than 4 times closer to the Sun since then. At that rate of brightening, I would put it at magnitude 7 on Nov. 9 and 3 on Nov. 22.

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