UCF professor finds that hottest measured extrasolar planet is 3700 degreesMay 10, 2007"HD 149026b is simply the most exotic, bizarre planet," Harrington said. "It's pretty small, really dense, and now we find that it's extremely hot." Using Spitzer, NASA's infrared space telescope, Harrington and his team observed the tiny planet disappear behind its star and reappear. Although the planet cannot be seen separately from the star, the dimming of the light that reached Spitzer told the scientists how much light the hot planet emits. From this they deduced the temperature on the side of the planet facing its star. The team's findings were published online in Nature today. Discovered in 2005, HD 149026b is a bit smaller than Saturn, making it the smallest extrasolar planet with a measured size. However, it is more massive than Saturn, and is suspected of having a core 70-90 times the mass of the entire Earth. It has more heavy elements (material other than hydrogen and helium) than exist in our whole solar system, outside the Sun. There are more than 230 extrasolar planets, but this is only the fourth of these to have its temperature measured directly. It is simple to explain the temperatures of the other three planets. However, for HD 149026b to reach 3700 degrees, it must absorb essentially all the starlight that reaches it. This means the surface must be blacker than charcoal, which is unprecedented for planets. The planet would also have to re-radiate all that energy in the infrared. "The high heat would make the planet glow slightly, so it would look like an ember in space, absorbing all incoming light but glowing a dull red," said Harrington. Drake Deming, of NASA's Goddard Space Flight Center in Greenbelt, MD, and a co-author of the Nature paper, thinks theorists are going to be scratching their heads over this one. "This planet is off the temperature scale that we expect for planets, so we don't really understand what's going on," Deming said. "There may be more big surprises in the future." Harrington's team on this project also included Statia Luszcz from the Center for Radiophysics and Space Research at Cornell University, who is now a graduate student at the University of California, Berkeley. Sara Seager, a theorist in the Departments of Earth, Atmospheric, and Planetary Sciences and of Physics at the Massachusetts Institute of Technology, and Jeremy Richardson, an observer from the Exoplanet and Stellar Astrophysics Laboratory at NASA Goddard, round out the team. Harrington is no stranger to significant findings. His research was published in Science magazine in October 2006 and in Nature in February 2007. In the first of those papers, Harrington's team used Spitzer to make the first measurement of day and night temperature variation on a different extrasolar planet. That research found that a Jupiter-like gas-giant planet circling very close to its sun is as hot as fire on one side, and potentially as cold as ice on the other, a condition that may also hold for HD 149026b. February's publication documented a landmark achievement. In a project led by Richardson, the group captured enough light from an exoplanet to spread it apart into a spectrum and find signatures of molecules in the planet's atmosphere - a key step toward being able to detect life on alien worlds. Harrington's team fared well in this year's stiff competition for observing time on NASA's orbiting infrared facility. They will observe HD 149026b using all of Spitzer's instruments in the coming year, to gain a better understanding of the planet's atmosphere. Harrington is a professor in UCF's growing program in planetary sciences. University of Central Florida |
|||||||||||||||||||||
| Related Extrasolar Planet Current Events and Extrasolar Planet News Articles Caltech scientists predict greater longevity for planets with life Roughly a billion years from now, the ever-increasing radiation from the sun will have heated Earth into inhabitability; the carbon dioxide in the atmosphere that serves as food for plant life will disappear, pulled out by the weathering of rocks; the oceans will evaporate; and all living things will disappear. NASA/University team develops new method to find alien oceans NASA-sponsored scientists looking back at Earth with the Deep Impact/EPOXI mission have developed a method to indicate whether Earth-like alien (extrasolar) worlds have oceans. New technique could find water on Earth-like planets orbiting distant suns Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter. Missing planets attest to destructive power of stars' tides During the last two decades, astronomers have found hundreds of planets orbiting stars outside our solar system. New research indicates they might have found even more except for one thing - some planets have fallen into their stars and simply no longer exist. Finding Twin Earths: Harder Than We Thought! Does a twin Earth exist somewhere in our galaxy? Astronomers are getting closer and closer to finding an Earth-sized planet in an Earth-like orbit. NASA's Kepler spacecraft just launched to find such worlds. European team finds smallest transiting extrasolar planet ever The CoRoT satellite has discovered a planet only twice as large as the Earth orbiting a star slightly smaller than the Sun. It is the smallest extrasolar planet (planet outside our solar system) whose radius has ever been measured. Hubble finds carbon dioxide on an extrasolar planet The NASA/ESA Hubble Space Telescope has discovered carbon dioxide in the atmosphere of a planet orbiting another star. Hubble finds first organic molecule on extrasolar planet The tell-tale signature of the molecule methane in the atmosphere of the Jupiter-sized extrasolar planet HD 189733b has been found with the Hubble Space Telescope. Under the right circumstances methane can play a key role in prebiotic chemistry - the chemical reactions considered necessary to form life as we know it. Deep Impact extended mission heads for comet Hartley 2 NASA has given a University of Maryland-led team of scientists the green light to fly the Deep Impact spacecraft to Comet Hartley 2 on a two-part extended mission known as EPOXI. The spacecraft will fly by Earth on New Year's Eve at the beginning of a more than two-and-a-half-year journey to Hartley 2. Hazy red sunset on extrasolar planet A team of astronomers have used the NASA/ESA Hubble Space Telescope to detect, for the first time, strong evidence of hazes in the atmosphere of a planet orbiting a distant star. The discovery comes after extensive observations made recently with Hubble's Advanced Camera for Surveys (ACS). More Extrasolar Planet Current Events and Extrasolar Planet News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||