Astronomy

Astronomers Claim Brown Dwarf Sun Lies beyond Pluto



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A team of Spanish astronomers claim they've discovered evidence of a significant object on the outskirts of the solar system. The object is so big it may have large satellites orbiting it. Officially it's named "G1.9."

What the team believes it has discovered is a brown dwarf star. If true, that would make our solar system a binary star system.

Binary star systems are not unusual. But the discovery comes after almost a decade of fevered speculation feeding conspiracy theories of a giant star named Nemesis or a Planet X that swings around the sun every 13,500, 27,000 or 55,000 years—take your pick.

Serious investigation of large objects long thought to be part of our system, yet well past the orbit of Pluto, have been dampened by the frenzy of true believers that are convinced a gigantic object will presage massive earth changes for either good or bad.

Now some new evidence has revealed there may well be such an object—or something similar—so the volume of the conspiracy enthusiasts will no doubt ratchet up.

While that might be beneficial for web traffic and late night talk show ratings, it doesn't help good science (or the knowledge that comes from it) move forward.

The Oort Cloud

Many star systems in the galaxy are binary (double) stars. Theoretically, binaries can be formed one of two ways: simultaneously from one collapsing mass of superheated gaseous matter; or they bifurcate and split apart creating two stars.

Data from hundreds of years of observations has revealed that binary stars sometimes both fully ignite and nuclear fusion takes place. Other times a smaller partner does not have enough critical mass to ignite fusion and so remains dim, burning only as a red or brown dwarf.

A dwarf star, while dim, still emits heat.

Two stars in the same system orbit about each other, the orbital point is known as the barycenter. A telltale wobble of the large companion star reveals the presence of the often all but invisible dwarf.

According to the Spanish astronomers' data, it appears that G1.9 is orbiting in a long elliptical loop between Pluto and the edge of the Oort Cloud.

The size of the brown dwarf is larger than Jupiter but smaller than a low mass star.

G1.9 is currently approximately 60 to 66 Astronomical Units from Earth. (1 AU = the distance from the Sun to Earth). In the sky it can be located in the vicinity of the Sagittarius constellation. The discovery seems to have occurred at G1.9's closest approach to us.

The solar systems 'belts'

Almost any schoolchild has heard of the asteroid belt composed primarily of ice, rock and metals. It exists between Mars and the giant gas planet Jupiter. Other belts, however, exist beyond that famous one.

The next belt that circles the sun is far beyond the lonely planetoid Pluto. There, in the icy depths of space lies a gigantic ring of water methane, ammonia and water called the Kuiper Belt.

Some evidence exists for a possible third belt, but it has not been proven yet so no name has been assigned to whatever may or may not exist there.

Beyond that theoretical third belt lies the known Oort Cloud: not a band or belt of debris, the cloud is an immense spherical shell that surrounds the entire solar system like a cloud. It's composed mostly of frozen particles of water, methane, ethane, carbon monoxide and hydrogen cyanide.

The region in many AUs in size as it extends to the very edge of the sun's gravitational field.

While the asteroid belts give birth to the asteroids and meteors that can impact the planets or fall into the sun, the Oort Cloud gives birth to comets. Some comets may be as big as planets—even bigger than Earth. A controversial theory states that Venus was once a comet in the not so distant past.

Evidence of G1.9's existence

Back in 1984 astronomer Dave Green of the University of Cambridge discovered evidence of the brown dwarf star. He didn't recognize it for what it was and it was tagged as the remains of a supernova.

The following year, NRAO's Very Large Array (VLA) radio telescope analyzed it more closely and concluded G1.9 was remarkably small for a supernova. The astronomical team confessed puzzlement and thought it odd that the object seemed to be less than 1,000 years old.

Then the mystery deepened.

NASA's orbiting Chandra X-ray Observatory discovered the "supernova" remnant was 16 percent larger than it had appeared during the last observations made during 1985. In the span of 22 years—from 1985 to 2007—the object had grown by 16 percent.

Astronomers were left scratching their heads. NASA arranged for the VLA to observe it again. The radio telescope confirmed Chandra's data; the object had grown significantly larger.

After recalculating the data, NASA announced that the object was much younger than originally thought and it was decided that G1.9 was a supernova that had exploded just 150 years earlier. This despite the fact that no historical record of a supernova observation exists cataloging such an object or explosion during the mid-1800s.  

While the nature of the object was still being debated, a large asteroid entered the solar system during 2009. It was captured by Jupiter's gravity field and fell into the giant gas planet. From the data, it's now strongly suspected that this previously unknown asteroid was affected by the gravity of G1.9 as it sped onwards in it elliptical orbit and tossed the large chunk of space debris spinning into the solar system.

The astronomers in Spain, extrapolating from the data that the object was no remnant of a supernova, anticipated its appearance and the increase in observable size. G1.9 is only visible in infrared wavelengths from the intense heat it radiates. Its visible light is so dim that it's lost against the background of other light in the galaxy.

Spanish astronomers have tracked this object with great interest because they were anticipating its appearance. Gravitational anomalies have been appearing in the Oort Cloud for some time, suggesting the perturbations were caused by a nearby object with considerable mass. The announcement that G1.9 had increased in size was no mystery to them. It is exactly what they would expect as the object moved closer to Earth.

Meanwhile back at NASA, astronomers are ignoring the Spaniards' data. They have their own theories that somehow remarkable dovetail with what the astronomers in Spain say they've already confirmed.

NASA's new calculations predict a deep space object as far as one light year from Earth in the Oort Cloud could be responsible for slinging asteroids into our solar system. The object would have to be at least 4 times the mass of Jupiter.

Now where have we heard that before?

Two astrophysicists at the University of Louisiana—John Matese and Daniel Whitmire—developed a new theory predicated on the idea that "something smaller than a Jovian mass would not be strong enough to perform the task."

Therefore, the two scientists believe our sun must have a companion.

"I think this whole issue will be resolved in the next five to 10 years," Matese said.

Maybe the two astrophysicists should place a call to the astronomers in Spain.

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