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Big, unseen planet may inhabit outer Solar System

March 27, 2014
Courtesy of the Carnegie Institution
and World Science staff

A newly dis­cov­ered “d­warf plan­et” is the fur­thest known plan­et-like body in our so­lar sys­tem—and a huge plan­et may in­hab­it that gen­er­al ar­ea as well, as­tro­no­mers re­port.

The dwarf plan­et, called 2012 VP113, is likely one of thou­sands of dis­tant ob­jects thought to pos­sibly form a group known as the in­ner Oort cloud, the re­search­ers said. 

An orbit di­a­gram for the out­er so­lar sys­tem. The Sun and Ter­res­tri­al plan­ets are at the cen­ter. 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. (Cred­it: Scott Shep­pard, Chad Tru­jil­lo)


Their work, pub­lished March 27 in the jour­nal Na­ture, points to the po­ten­tial pres­ence of a huge plan­et, per­haps up to 10 times Earth’s size, pos­sibly in­flu­enc­ing the way oth­er in­ner Oort cloud ob­jects or­bit around the Sun.

This “re­de­fines our un­der­stand­ing of our so­lar sys­tem,” said Lin­da El­kins-Tan­ton, di­rec­tor of the de­part­ment of ter­res­tri­al mag­net­ism at the Car­ne­gie In­sti­tu­tion in Wash­ing­ton, D.C., which was in­volved in the work.

The known So­lar Sys­tem can be di­vid­ed in­to three parts: rocky plan­ets like Earth, close to the Sun; gas gi­ant plan­ets, fur­ther out; and the fro­zen ob­jects of the “Kui­per belt,” which lie just be­yond the or­bit of the gas gi­ant Nep­tune. 

Further out, the sci­en­tists said, there seems to be an “edge” to the So­lar Sys­tem be­yond which only one ob­ject, Sed­na, was pre­vi­ously known to ex­ist for its whole or­bit, but the new­found body has an or­bit that stays even fur­ther.

Sed­na was found be­yond the Kui­per Belt edge in 2003. It was­n’t known if Sed­na was alone. The new find­ing shows it’s not and is part of the hy­poth­e­sized in­ner Oort cloud, the likely or­i­gin of some com­ets, the re­search­ers said.

2012 VP113’s clos­est or­bit point to the Sun brings it to about 80 times fur­ther from the Sun than the Earth is, they added. Pre­vi­ously, only Sed­na was known to con­sist­ently in­hab­it a realm sig­nif­i­cantly fur­ther than 50 times that dis­tance.

In the stu­dy, Scott Shep­pard of the Car­ne­gie In­sti­tu­tion and Chad­wick Tru­jil­lo of the Gem­i­ni Ob­serv­a­to­ry in Ha­waii and Chil­e used the new Dark En­er­gy Cam­era on the NOAO 4 me­ter tel­e­scope in Chil­e. The Ma­gel­lan 6.5-me­ter tel­e­scope at Car­ne­gie’s Las Cam­panas Ob­serv­a­to­ry was used to ex­am­ine the new ob­ject’s or­bit and sur­face prop­er­ties.

From the amount of sky searched, Shep­pard and Tru­jil­lo con­clude that about 900 ob­jects with or­bits like Sedna and 2012 VP113 wid­er than 1,000 km (600 miles) may ex­ist and that the in­ner Oort cloud’s popula­t­ion likely ex­ceeds that of the Kuiper Belt and main as­ter­oid belt.

“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,” said Shep­pard.

Both Sedna and 2012 VP113 were found near their clos­est ap­proach to the Sun, but both have or­bits es­ti­mat­ed to go out to hun­dreds of times the Earth-Sun dis­tance, where they would be too faint to find. In fact, the si­m­i­lar­ity in the or­bits found for Sedna, 2012 VP113 and a few oth­er ob­jects near Kuiper Belt’s edge sug­gests an “un­known mas­sive per­turb­ing body,” the pos­sible “Su­per Earth,” may be shep­herd­ing these ob­jects in­to si­m­i­lar or­bits, the sci­en­tists said.

Be­yond the in­ner Oort Cloud is be­lieved to lie the out­er Oort cloud, start­ing around 1,500 times the Earth-Sun dis­tance, where the gra­vity from oth­er stars affects the or­bits of ob­jects.


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A newly discovered “dwarf planet” is the furthest known planet-like body in our solar system—and a huge planet may inhabit that general area as well, astronomers report. The dwarf planet, called 2012 VP113, was detected beyond the Solar System’s known “edge.” It’s likely one of thousands of distant objects thought to possibly form a group known as the inner Oort cloud, the researchers said. Their work, published March 27 in the journal Nature, points to the potential presence of a huge planet, perhaps up to 10 times Earth’s size, possibly influencing the way other inner Oort cloud objects orbit around the Sun. The known Solar System can be divided into three parts: rocky planets like Earth, close to the Sun; gas giant planets, further out; and the frozen objects of the “Kuiper belt,” which lie just beyond the orbit of the gas giant Neptune. Beyond that, the scientists said, there seems to be an edge to the Solar System where only one object, Sedna, was previously known to exist for its whole orbit, but the newfound body has an orbit that stays even further. “This is an extraordinary result that redefines our understanding of our Solar System,” said Linda Elkins-Tanton, director of the department of terrestrial magnetism at the Carnegie Institution in Washington, D.C. Sedna was found beyond the Kuiper Belt edge in 2003. It wasn’t known if Sedna was alone. The new finding shows it’s not and is part of the hypothesized inner Oort cloud, the likely origin of some comets, the researchers said. 2012 VP113’s closest orbit point to the Sun brings it to about 80 times further from the Sun than the Earth is, they added. Previously, only Sedna was known to consistently inhabit a realm significantly further than 50 times that distance. In the study, Scott Sheppard of the Carnegie Institution and Chadwick Trujillo of the Gemini Observatory in Hawaii and Chile used the new Dark Energy Camera on the NOAO 4 meter telescope in Chile. The Magellan 6.5-meter telescope at Carnegie’s Las Campanas Observatory was used to examine the new object’s orbit and surface properties. From the amount of sky searched, Sheppard and Trujillo conclude that about 900 objects with orbits like Sedna and 2012 VP113 wider than 1,000 km (600 miles) may exist and that the inner Oort cloud’s total population is likely bigger than that of the Kuiper Belt and main asteroid belt. “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,” said Sheppard. Both Sedna and 2012 VP113 were found near their closest approach to the Sun, but both have orbits estimated to go out to hundreds of times the Earth-Sun distance, where they would be too faint to find. In fact, the similarity in the orbits found for Sedna, 2012 VP113 and a few other objects near Kuiper Belt’s edge suggests an “unknown massive perturbing body,” the possible “Super Earth,” may be shepherding these objects into similar orbits, the scientists said. Beyond the inner Oort Cloud is believed to lie the outer Oort cloud, starting around 1,500 times the Earth-Sun distance, where the gravity from other stars perturbs the orbits of the objects.