Scientists have discovered our solar system's sun to have a tail, but this does not make it a comet, according to a study conducted by a team of researchers.
Using data from NASA's Interstellar Boundary Explorer (IBEX) spacecraft, scientists saw the sun's tail, a characteristic often shared by both stars and comets. The sun's was not quite as easy to spot as other stars' tails can be.
"By examining the neutral atoms, IBEX made the first observations of the heliotail. Many models have suggested the heliotail might be like this or like that, but we've had no observations. We always drew pictures where the tail of the heliosphere just disappears off the page, since we couldn't even speculate about what it really looked like," said lead author David McComas.
The study published Wednesday in the Astrophysical Journal details their discovery.
"Scientists always presumed the heliosphere had a tail," IBEX mission scientist Eric Christian said at a press conference Wednesday. "But this is the first real data we have that gives us the shape of the tail. We've never taken a picture of it."
Although stars are known to have tails similar to comets, the sun's was not easy to spot because it does not shine. McComas said his team used three years of imagery taken by the IBEX satellite to figure out the shape of the tail.
IBEX used technology called energetic neutral atom imaging, which measures the neutral particles within the heliosphere. The team of scientists could not give a an accurate measurement to the length of the tail, but did say it is 1,000 times longer than the distance to Earth, at most.
"Many models have suggested the heliotail might look like this or that, but we have had no observations," McCormas said. "[Scientists] always drew pictures where the tail of the solar system just trailed off the page, since we couldn't even speculate about what it really looked like."
