WASHINGTON, Jan. 7 (UPI) -- Astronomers on Monday said by using optical telescopes they have been able to snap pictures of a supermassive object orbiting a nearby star.
They classify the object a "brown dwarf," a collection of matter far heavier than planets, but not massive enough to sustain the nuclear fusion reactions of a true star, said Michael Liu, an astronomy professor at the University of Hawaii's Institute for Astronomy and lead author of a paper presented at the American Astronomical Society's annual meeting.
The body contains at least 55 times as much mass as the planet Jupiter -- outweighing all the Solar System's planets dozens of times over, Liu said. Despite its size and mass, however, the dwarf is very close to its parent star, a veritable twin of Earth's Sun, about 58 light-years away in the constellation Sagitta or The Arrow, he said.
The dwarf was detected because it emits its own light, glowing as it contracts and cools millions of years after its formation. If it existed in the Solar System, Liu said, it would be visible at night as a deep red point of light thousands of times brighter than Jupiter.
If the Sagitta system was superimposed on our own, the dwarf's orbit would place it between Saturn and Uranus, making it the smallest separation between a star and its companion ever detected by optical astronomy, Liu said.
"Only by using adaptive optics to produce very sharp images could we have found this companion," Liu said in a statement. "It is too faint and too close to its parent star to be seen otherwise."
His team used the Gemini North and Keck telescopes on Hawaii's Mauna Kea volcano, which rely on computer-controlled "adaptive optics" to eliminate the optical fuzziness caused by the Earth's atmosphere, to spot the dwarf.
Up to now, astronomers have relied on spotting "wobbles" in a star's motion to determine the presence of planets, Liu said. Such methods first suggested the brown dwarf's presence, he added, and the team's findings will help improve that approach to planet detection.
The dwarf's close proximity to the Sagitta star calls into question current theories on how planetary systems are formed.
One line of reasoning suggests that after a star first ignites, gas and dust begin to swirl around it in a huge disc, which then coalesces into small rocky planets near the star and larger, gaseous bodies farther out, as in Earth's Solar System.
Another theory suggests a pre-star mass could split before ignition, leaving a star and a brown dwarf, but the separations seen in such cases are dozens or hundreds of times greater than what's observed in the Sagitta system, Liu said.
"(The observations tell) us there is a diversity of other solar systems possible around stars like the Sun," Liu told United Press International. They also provide more evidence as to how out of the ordinary our system is, he said.
Astronomers have seen brown dwarves exist without an accompanying star, said Alan Boss, an expert on stellar and planetary system formation at the Carnegie Institution of Washington. It is very unlikely the Sagitta star captured such a body, however, since that region of space is not crowded enough to bring two objects together in the right manner, he said.
Further observations are needed to see if the Sagitta star has other planets or if the dwarf has some of its own, Boss and Liu said.
Boss said the benefits provided by adaptive optics have up to now only been an appetizing glimpse of what they can do -- he expects telescopes with these features to spot a planet in the throes of creation within a few years.
"For astronomers, this is really the embodiment of truth and beauty in revealing things," Boss said. "It's changing an astronomical image from something that looks like a fuzzy, impressionistic painting into something that looks like a photrealistic painting."
