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A young, free-floating world sits alone in space in this illustration. The object, called WISEA J114724.10−204021.3, is thought to be an exceptionally low-mass "brown dwarf," which is a star that lacked enough mass to burn nuclear fuel and glow like a star. Astronomers using data from NASA's WISE and 2MASS sky surveys found the object in TW Hydrae – a young, 10-million-year-old association of stars.
Specifically, scientists think the youthful brown dwarf belongs to a class called "L dwarfs" and has a temperature of about 2,250 degrees Fahrenheit. The object would appear reddish in hue. It has a mass between about 5 and 10 times that of Jupiter.
NASA's Jet Propulsion Laboratory in Pasadena, California, managed and operated WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode in 2011, after it scanned the entire sky twice, completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify potentially hazardous near-Earth objects. The 2MASS mission was a joint effort between the California Institute of Technology, Pasadena; the University of Massachusetts, Amherst; and JPL. Caltech manages JPL for NASA. WISE, NEOWISE and 2MASS data are archived at the Infrared Processing and Analysis Center, or IPAC, at Caltech.
Image credit: NASA/JPL-Caltech
April 19, 2016
In 2011, astronomers announced that our galaxy is likely teeming with free-floating planets. In fact, these lonely worlds, which sit quietly in the darkness of space without any companion planets or even a host sun, might outnumber stars in our Milky Way galaxy. The surprising discovery begged the question: Where did these objects come from? Are they planets that were ejected from solar systems, or are they actually light-weight stars called brown dwarfs that formed alone in space like stars?
A new study using data from NASA's Wide-field Infrared Survey Explorer, WISE, and the Two Micron All Sky Survey, or 2MASS, provides new clues in this mystery of galactic proportions. Scientists have identified a free-floating, planetary-mass object within a young star family, called the TW Hydrae association. The newfound object, termed WISEA J114724.10−204021.3, or just WISEA 1147 for short, is estimated to be between roughly five to 10 times the mass of Jupiter.
WISEA 1147 is one of the few free-floating worlds where astronomers can begin to point to its likely origins as a brown dwarf and not a planet. Because the object was found to be a member of the TW Hydrae family of very young stars, astronomers know that it is also very young -- only 10 million years old. And because planets require at least 10 million years to form, and probably longer to get themselves kicked out of a star system, WISEA 1147 is likely a brown dwarf. Brown dwarfs form like stars but lack the mass to fuse atoms at their cores and shine with starlight.
Scientist explained that they discovered that the planet returning around a star, these objects are likely to rebuttal all known theories of planets, Scientist they also noted that, there would be life in the new planets.According to research conclusions, which published on Thursday in the journal Nature, astronomers discovered 10 Jupiter-sized planets, which 10.000 -- 20.000 light years from to earth.
The scientists in the Japan/NZ MOA (MicrolensingObservations in Astrophysics) collaboration used a 1.8m telescope at Mt John University Observatory near Lake Tekapo, with support from researchers at Auckland, Massey, Victoria and Canterbury universities.
They suggested today that the planets may have formed in dense gas clouds around newly formed stars and were then scattered into unbound or very distant orbits, so that there are twice as many of these as planets tied to stars.
Kailash Sahu, of the Space Telescope Science Institute, and colleagues monitored 83,000 stars and found a normal dwarf star -- about one tenth the mass of our sun -- which focused the light of the background star, causing it to appear 10 times brighter before it returned to normal over a period of 18 days.
But those researchers also found half a dozen smaller objects about 8500 light-years from Earth -- where a background star doubled in brightness for less than 20 hours -- and these appeared to be wandering planets plying their own course in the distant sea of stars.
Massey University astrophysicist Dr Ian Bond, a co-author of the Nature paper, said MOA typically found 500-600 microlensing events each year. Similar work is done by the Polish OGLE telescope that operates from Las Campanas in Chile.
He said the timescale of less than two days over which wandering planets bent the light of a background star made them hard to detect.
"Our results point to a population of free floating planets of around Jupiter mass," he said.
Jupiter is nearly 11 times the diameter of the earth, and about a tenth the size of the Earth's sun.
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