Frozen world spotted on fringes of solar system
LOS ANGELES — Peering into the far reaches of the solar system, astronomers have spied a pink, frozen world, 7½ billion miles from the sun.
It's the second such object to be discovered in a region of space beyond Pluto long considered a celestial wasteland. Until now, the lone known resident in this part of the solar system was an oddball dwarf planet spotted in 2003 named Sedna after the mythological Inuit goddess who created the sea creatures of the Arctic.
The latest discovery shows “Sedna is not a freak. We can have confidence that there is a new population to explore,” Yale University senior research scientist David Rabinowitz said in an email. He was one of Sedna's discoverers, but had no role in the new find detailed in Thursday's issue of the journal Nature.
For years, astronomers hunted in vain for other Sednas in the little-studied fringes of the solar system.
The new object, 2012 VP113, was tracked using a camera on a ground telescope in Chile by Scott Sheppard of the Carnegie Institution for Science in Washington and Chad Trujillo of the Gemini Observatory in Hawaii. Trujillo was part of the team that found Sedna.
Like Sedna, VP is a dwarf planet. It's jokingly nicknamed “Biden” after Vice President Joe Biden because of the object's initials. It measures about 280 miles across, or half the diameter of Sedna. It's bone-chilling cold, with a temperature of about minus 430 degrees Fahrenheit.
Unlike red and shiny Sedna, the newfound object is pink and much fainter, which made it hard to detect.
By contrast, Earth is about 7,900 miles across and 93 million miles from the sun.
Sedna and VP reside in what's known as the inner Oort cloud in the outer edge of the solar system where some comets such as the sun-diving Comet ISON are thought to originate. ISON broke apart last year after brushing too close to the sun.
Far from being deserted, Sheppard and Trujillo estimate there are probably thousands of similar objects in the inner Oort cloud.
“These objects are not unique. There's a huge number out there,” Sheppard said.