Clouds of Water Possibly Found in Brown Dwarf Atmosphere
Extreme Space Weather
Oct. 3, 2011 --
With hurricanes, floods, massive thunderstorms, heat waves and wildfires, we might be inclined to believe that the weather on Earth is sometimes less than hospitable to the life that inhabits it. But compared to other planets, stars and other bodies in the cosmos, the weather on Earth is downright mild. In this slide show, explore what conditions are like elsewhere in the universe. By the time you're done reading this slide show, you'll know exactly what to say the next time you hear someone whining about the weather: "Quit complaining. At least we don't live on HD 209458b."
Credit: Paul A. Kempton
The Sauna Planet "It's not the heat; it's the humidity" is a common expression on especially muggy days in the heat of the summer. But on exoplanet GJ 1214b, we guarantee you won't notice the difference. Located about 40 light-years from our planet, this super-Earth waterworld is believed to possess an atmosphere of dense steam. The exoplanet is between two and 10 times larger than Earth and located approximately 70 times closer to its parent star. Essentially, this planet is one giant sauna, turned up to temperatures in excess of 1,000 degrees Fahrenheit (537 degrees Celsius).
Mars Storms Hurricanes are the largest storms on Earth. With powerful wind gusts and heavy rains, the storms can take a devastating toll on millions at a time. But in terms of size, they can't compare to the dust storms that can roll across Mars and affect the entire planet. In fact, some storms are so large that amateur astronomers can occasionally view them using ground based telescopes. During dust storms, wind gusts can reach up to 300 miles per hour, far stronger than any storm ever recorded on Earth.
Supersonic Planet If you're a windsurfing enthusiast, HD189733b may be just the right place for you. That is, at least it would be if it weren't 60 light-years away and orbiting its parent star so closely. Classified as a hot Jupiter, this gas giant hosts wind speeds that exceed the speed of sound. And since, as Adam Showman of the University of Arizona Lunar and Planetary Laboratory explains, the speed of sound of HD189733b is 10 times faster than it is on Earth, that's a pretty significant accomplishment. To put a number on it, the winds can reach speeds of around 6,700 miles (10,870 kilometers) per hour. That should help to cool down any potential visitors, since the temperature on the surface of the planet facing the sun can reach 1,700 degrees Fahrenheit (926 degrees Celsius).
Tidally Locked World Located some 150 light-years from Earth, HD 209458b is a hot Jupiter with one major convenience: You never have to bother to set your watch. The planet is in a tidally locked orbit with its parent star, meaning one side is always facing the sun and the other side is stuck in perpetual night. Because of this disparity, the planet also has strong winds similar to those of HD189733b. However, wind speeds on this planet only reach 4,500 miles per hour, making it a better option for a thrill-seeking windsurfer who might still be holding out hope of keeping a hair or two in place.
Credit: Jon Lomberg/Univ. of Toronto
Forget Jupiter The swirling storm at the center of Jupiter's Great Red Spot might get all the attention in our solar system. But that storm is a tiny tyke compared to the one on this brown drawf. Affectionately called "2MASS J21392676+0220226," this brown dwarf is located approximately 47 light-years away.
Solar Storms Unlike the weather mentioned in every other entry on this slide show, storms on the sun can have a significant impact on life on Earth. As storm activity increases in frequency as the sun approaches its solar maximum in its 11-year cycle, solar flares and coronal mass ejections can threaten the functionality of satellite systems, affecting computer, navigation and telecommunications networks on Earth, as well as potentially disrupt power grids. Unfortunately, an umbrella won't do us much good in the event of a massive solar storm as the sun blasts plasma particles at Earth at speeds of hundreds of miles per hour. But that doesn't mean there's reason to panic, either. (Not yet, anyway.)
Credit: ESA/V. Beckmann (NASA-GSFC)
Honorable Mention: Black Holes If you're chasing massive storms in space, nothing quite rivals the strength and intensity of the tidal forces created by a hungry black hole. When black holes tear into stars, they pull in gasses from that star at such high speeds as to create bright gamma-ray bursts that are detectable from Earth. Anything that comes near a black hole is stretched out, then ripped apart and smashed together again with other matter at velocities approaching the speed of light. If there's one storm you absolutely don't want to get caught in this year, it's one created by drifting too close to a black hole.
More stories by Talal Al-Khatib.
Finding clouds of water floating in the atmosphere of an alien world is a significant find. Now, astronomers have reported preliminary findings that water clouds have been detected in the atmosphere of a brown dwarf, a mere 7.3 light-years from Earth.
But don’t dream of an alien planet with white, fluffy clouds rolling over a habitable terrain, brown dwarfs are cool failed stars with thick churning atmospheres, the antithesis of a life-giving habitat (as we know it).
The brown dwarf, called WISE J0855-0714, was discovered hiding in archived data from NASA’s Wide-field Infrared Survey Telescope (WISE) and is notable in that is the coolest brown dwarf known. It has a temperature slightly lower than the freezing point of water and a mass roughly ten times that of Jupiter.
The best thing about this object is that it is an interstellar loner — it doesn’t orbit a star and drifts through space solo. This means its infrared signal could be isolated, with no host starlight overwhelming its detection.
Follow-up observations by the 6.5-meter Magellan Baade telescope in Chile by Jacqueline Faherty of the Carnegie Institution for Science in Washington, D.C., acquired 151 near-infrared images of the intriguing object, and after comparing radiation generated by the brown dwarf with atmospheric models, astronomers have announced the possible presence of water clouds high in the dwarf planet’s atmosphere. The research has been published in the Astrophysical Journal Letters.
“It’s incredibly interesting,” said Jonathan Fortney of the University of California, Santa Cruz, who was involved with the development of the brown dwarf models. “It’s tentative,” but “it’s the first evidence for water clouds” outside our solar system,” he told Science News.
Water clouds exist on Earth and Mars, and water is known to exist in the lower layers of the gas and ice giants. But until now, no other object beyond the solar system has exhibited clouds of water.
Water vapor has been detected in extrasolar planets’ atmospheres, however, but this is the first time water clouds have been spotted. Like Earth, it appears to be partly cloudy, with broken patches of water clouds, said Faherty.
This is an important discovery for brown dwarf science. These sub-stellar objects are not massive enough to sustain fusion in their cores, so they’re not stars. But they have massive un-differentiated atmospheres that make them very different from planets. They occupy a strange hinterland between the most massive gas giant planets (like Jupiter) and the smallest stars (like red dwarfs).
Although we have to wait until NASA’s James Webb Telescope launches in 2018 to acquire a spectra of the infrared radiation before we know for certain if it is indeed water, it’s a fascinating discovery that gives this particular brown dwarf a very planet-like twist.
Source: Science News