Record-Breaking Radio Waves from Ultra-Cool StarApril 30, 2012
Penn State University astronomers using the world's largest radio telescope, at Arecibo, Puerto Rico, have discovered flaring radio emissions from an ultra-cool star, not much warmer than the planet Jupiter, shattering the previous record for the lowest stellar temperature at which radio waves were detected.
The team from Penn State's Department of Astronomy and Astrophysics and the Center for Exoplanets and Habitable Worlds, led by Alex Wolszczan, the discoverer of the first planets ever found outside our solar system, has been using the giant 305-m (1000-ft) telescope to look for radio signals from a class of objects known as brown dwarfs. These objects are small, cold stars that bridge the gap between Jupiter-like giant planets and normal, more-massive, hydrogen-fusing stars. The astronomers hit the jackpot with a star named J1047+21, a brown dwarf 33.6 light years away in the constellation Leo, in a result that could boost the odds of discovering life elsewhere in the universe.
Matthew Route, a graduate student at Penn State and the lead author of the discovery paper, said, "This object is the coolest brown dwarf ever detected emitting radio waves -- it's half the temperature of the previous record holder, making it only about five times hotter than Jupiter."
The new radio-star is much smaller and colder than our Sun. With a surface temperature not much higher than that of a giant planet, and a size comparable to Jupiter's, it is scarcely visible in optical light. Yet the radio flares seen at Arecibo show it must have a strong magnetic field, implying that the same could be true of other similar stars.
Wolszczan, an Evan Pugh Professor of Astronomy and Astrophysics and the leader of the project, said, "This is a really exciting result. We hope that in the future we'll be able to detect yet colder brown dwarfs, and possibly even giant planets around other stars."
The possibility that young, hot planets around other stars could be detected in the same manner -- because they still maintain strong magnetic fields -- has implications for the chances of finding life elsewhere in our Milky Way Galaxy, Wolszczan explained. "The Earth's field protects life on its surface from harmful particles of the solar wind. Knowing whether planetary magnetic fields are common or not throughout the Galaxy will aid our efforts to understand chances that life may exist beyond the Solar System."
The discovery of radio signals from J1047+21 dramatically broadens the window through which astronomers can study the atmospheres and interiors of these tiny stars, using the radio detection of their magnetic fields as a tool. At the temperature of this brown dwarf, its atmosphere must be made of neutral gas, which would not give off radio signals like those seen. SO The energy to drive the signals is likely to come from magnetic fields deep inside the star, similar to the field that protects the Earth from dangerous high-energy particles. By monitoring the radio flares from J1047+21, astronomers will be able to tell how stable the magnetic field is over time, and, from flare duration, they can infer the size of the emitter itself. The results were published in the March 10 2012 edition of the Letters section of the Astrophysical Journal.
The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968), and in alliance with Ana G. Méndez-Universidad Metropolitana, and the Universities Space Research Association.
The Pennsylvania State University
Related Magnetic Fields Current Events and Magnetic Fields News Articles
Astronomers find giant planet around very young star
In contradiction to the long-standing idea that larger planets take longer to form, U.S. astronomers today announced the discovery of a giant planet in close orbit around a star so young that it still retains a disk of circumstellar gas and dust.
New tabletop instrument tests electron mobility for next-generation electronics
The National High Magnetic Field Laboratory, with facilities in Florida and New Mexico, offers scientists access to enormous machines that create record-setting magnetic fields.
Virginia Tech researchers in the Antarctic discover new facets of space weather
A team of National Science Foundation (NSF)-supported researchers at the Virginia Polytechnic Institute and State University (Virginia Tech) discovered new evidence about how the Earth's magnetic field interacts with solar wind, almost as soon as they finished installing six data-collection stations across East Antarctic Plateau last January.
NASA mini-balloon mission maps migratory magnetic boundary
During the Antarctic summer of 2013-2014, a team of researchers released a series of translucent scientific balloons, one by one.
Space mission first to observe key interaction between magnetic fields of Earth and sun
Most people do not give much thought to the Earth's magnetic field, yet it is every bit as essential to life as air, water and sunlight.
Spacecraft fly through explosive magnetic phenomenon to understand space weather
For the first time, spacecraft have flown through the heart of a magnetic process that controls Earth's space weather and geomagnetic storms.
NASA directly observes fundamental process of nature for 1st time
Like sending sensors up into a hurricane, NASA has flown four spacecraft through an invisible maelstrom in space, called magnetic reconnection.
Distance wireless charging enhanced by magnetic metamaterials
Wireless charging of mobile devices is possibly one of the most desired technological milestones. Some devices can already be charged wirelessly by placing the mobile device on top of a charging base.
Dartmouth-led team devises new technique to probe 'noise' in quantum computing
Dartmouth College and Griffith University researchers have devised a new way to "sense" and control external noise in quantum computing.
Princeton graduate student creates program that helps stabilize fusion plasma
ImÃ®ne Goumiri, a Princeton University graduate student, has worked with physicists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) to simulate a method for limiting instabilities that reduce the performance of fusion plasmas.
More Magnetic Fields Current Events and Magnetic Fields News Articles