New Planet Discovered in Far Perimeter of Solar System
The discovery of a distant dwarf planet in the far reaches of our solar system suggests that there may be a lot more beyond the system's perimeter than meets the eye.
The new dwarf planet, known for the time being as 2012 VP113, is only the second such object to be found orbiting the outer perimeter of our solar system in a region known as the Oort Cloud. However, the dwarf planet's discovery hints that there may be many more of these distant and icy worlds that we have not yet seen in our own stellar backyard.
The orbit of this new dwarf planet - which lurks about 250 times farther away from the Sun than Earth - is likely influenced by an even bigger planet hiding somewhere in the dim reaches of the solar system. The object is so distant that astronomers had not ever seen an object moving so slowly through space, according to a report on the Nature blog.
Astronomers are theorizing that the same mystery plant could also influence the orbit of the other only known dwarf planet in the Oort Cloud, an object known as Sedna.
Writing in the journal Nature, Scott Sheppard of the Carnegie Institution of Science and Chadwick Trujillo of the Gemini Observatory report that there are likely many more objects are waiting to be found in the Oort Cloud and that an enormous planet, perhaps up to 10 times the size of Earth, is also influencing the orbit of these dwarf planets from a currently unknown location.
Based on the swath of sky the astronomers surveyed - equal to the space about 220 full Moons would take up - the they concluded that around 900 objects with orbits like Sedna and 2012 VP113 and a size greater than 1,000 kilometers across are out there waiting to be found. The researchers are currently tracking at least six potential candidates.
"Some of these inner Oort cloud objects could rival the size of Mars or even Earth. This is because many of the inner Oort cloud objects are so distant that even very large ones would be too faint to detect with current technology," Sheppard said in a statement from Carnegie.
"The search for these distant inner Oort cloud objects beyond Sedna and 2012 VP113 should continue, as they could tell us a lot about how our Solar System formed and evolved," Sheppard said.
At about 450 kilometers across 2012 VP113 is about half the size of Sedna and is likely made of ice, the researchers report.
The astronomers estimate that it takes about 4,000 years for the dwarf planet to orbit the Sun.
Michael Brown, a planetary astronomer at the California Institute of Technology in Pasadena, told the Nature blog that astronomers have long been searching for objects like Sedna, and now finding one reduces the chances of Sedna being a fluke.
"But astronomers now have to come up with ideas to explain how these objects remain tightly gravitationally bound to the Sun when they orbit so far away," Nature reported. One theory is that during the solar system's infancy a nearby star's gravity disrupted the forming solar system and dragged some fragments out towards the edge. Another possibility is that a massive rogue planet passed through at some point and knocked objects that were closer out to the perimeter of the system.
Either way, the distance of the newfound dwarf planet is staggering. The object gets no closer than 12 billion kilometers from the Sun and at is farthest point is some 67 billion kilometers away from the star it orbits. Earth, on the other hand is just 149 million km from the Sun, and even Neptune - the most distant planet - is only 4.5 billion km away.
"To all intents and purposes, in the current architecture of the solar system, Sedna and 2012 VP113 should not be there," astronomer Megan Schwamb of Taiwan's Academia Sinica, said in a commentary accompanying the study, as reported by National Geographic. "This suggests that Sedna and 2012 VP113 are the tip of the iceberg."
In the image below, the Sun and inner planets are at the center and too small to see. The orbits of the four giant planets, Jupiter, Saturn, Uranus and Neptune, are shown by purple solid circles. The Kuiper Belt, including Pluto, is shown by the dotted light blue region just beyond the giant planets. Sedna's orbit is shown in orange while 2012 VP113's orbit is shown in red. Both objects are currently near their closest approach to the Sun (perihelion). They would be too faint to detect when in the outer parts of their orbits. Notice that both orbits have similar perihelion locations on the sky and both are far away from the giant planet and Kuiper Belt regions. Image is courtesy of Scott Sheppard.