The observable Solar System can be divided into three distinct regions: the rocky terrestrial planets including the asteroids at 0.39 to 4.2 astronomical units (au) from the Sun (where 1 au is the mean distance between Earth and the Sun), the gas giant planets at 5 to 30 au from the Sun, and the icy Kuiper belt objects at 30 to 50 au from the Sun. The 1,000-kilometre-diameter dwarf planet Sedna was discovered ten years ago and was unique in that its closest approach to the Sun (perihelion) is 76 au, far greater than that of any other Solar System body1. Formation models indicate that Sedna could be a link between the Kuiper belt objects and the hypothesized outer Oort cloud at around 10,000 au from the Sun2, 3, 4, 5, 6. Here we report the presence of a second Sedna-like object, 2012 VP113, whose perihelion is 80 au. The detection of 2012 VP113 confirms that Sedna is not an isolated object; instead, both bodies may be members of the inner Oort cloud, whose objects could outnumber all other dynamically stable populations in the Solar System.
- Discovery of a candidate inner Oort cloud planetoid. Astrophys. J. 617, 645–649 (2004) , &
- Scenarios for the origin of the orbits of the trans-Neptunian objects 2000 CR105 and 2003 VB12 (Sedna). Astron. J. 128, 2564–2576 (2004) &
- Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits. Nature 432, 598–602 (2004) &
- Sculpting the outer Edgeworth Kuiper belt: stellar encounter followed by planetary perturbations. Icarus 173, 559–573 (2005) , &
- A distant planetary-mass solar companion may have produced distant detached objects. Icarus 184, 589–601 (2006) , &
- Models of the collisional damping scenario for ice-giant planets and Kuiper belt formation. Icarus 189, 196–212 (2007) &
- Final stages of planet formation. Astrophys. J. 614, 497–507 (2004) , &
- Instability-driven dynamical evolution model of a primordially five-planet outer Solar System. Astrophys. J. 744, L3 (2012) , &
- Statistical study of the early Solar System's instability with four, five, and six giant planets. Astron. J. 144, 117 (2012) &
- On the origin of the high-perihelion scattered disk: the role of the Kozai mechanism and mean motion resonances. Celestial Mech. Dyn. Astron. 91, 109–129 (2005) , , &
- Comparison of forming mechanisms for Sedna-type objects through an observational simulator. Astron. Astrophys. 553, A110 (2013) &
- Production of the extended scattered disk by rogue planets. Astrophys. J. 643, L135–L138 (2006) &
- Evidence for early stellar encounters in the orbital distribution of Edgeworth-Kuiper belt objects. Astrophys. J. 528, 351–356 (2000) , &
- A two-stage formation process for the Oort comet cloud and its implications. Astron. Astrophys. 492, 251–255 (2008)
- Reassessing the formation of the inner Oort cloud in an embedded star cluster. Icarus 217, 1–19 (2012) , , , &
- Was the Sun born in a massive cluster? Astrophys. J. 754, 56 (2012) &
- Early evolution of the birth cluster of the solar system. Astron. Astrophys. 549, A82 (2013)
- The birth environment of the Solar System. Annu. Rev. Astron. Astrophys. 48, 47–85 (2010)
- Sedna and the Oort cloud around a migrating Sun. Icarus 215, 491–507 (2011) , &
- Capture of the Sun's Oort cloud from stars in its birth cluster. Science 329, 187–190 (2010) , , &
- Properties of the distant Kuiper belt: results from the Palomar Distant Solar System Survey. Astrophys. J. 720, 1691–1707 (2010) , , &
- The Canada-France Ecliptic Plane Survey—full data release: the orbital structure of the Kuiper belt. Astron. J. 142, 131 (2011) et al.
- The small numbers of large Kuiper belt objects. Astron. J. 147, 2 (2014) , &
- Evidence for an extended scattered disk. Icarus 157, 269–279 (2002) et al.
- 259–273 (2008) , , & in The Solar System Beyond Neptune (eds , , , & ).
- Exploring the outer Solar System with the ESSENCE Supernova Survey. Astrophys. J. 682, L53–L56 (2008) et al.
- Discovery of a new member of the inner Oort cloud from the Next Generation Virgo Cluster Survey. Astrophys. J. 775, L8 (2013) et al.
- Secular perturbations of asteroids with high inclination and eccentricity. Astron. J. 67, 591 (1962)
- Embedded star clusters and the formation of the Oort cloud. Icarus 184, 59–82 (2006) , &
- A southern sky and galactic plane survey for bright Kuiper belt objects. Astron. J. 142, 98 (2011) et al.
- The Dark Energy Survey Camera (DECam). Phys. Proc. (Proc. 2nd Int. Conf. on Technology and Instrumentation in Particle Physics, TIPP 2011) 37, 1332–1340 (2012)
- Properties of the trans-Neptunian belt: statistics from the Canada-France-Hawaii telescope survey. Astron. J. 122, 457–473 (2001) , &
- Orbit fitting and uncertainties for Kuiper belt objects. Astron. J. 120, 3323–3332 (2000) &
- 91–104 (2008) , , & in The Solar System Beyond Neptune (eds , , , & ).
- The colors of extreme outer Solar System objects. Astron. J. 139, 1394–1405 (2010)
- 161–179 (2008) et al. in The Solar System Beyond Neptune (eds , , , & ).
- Unbiased inclination distributions for objects in the Kuiper belt. Astron. J. 140, 350–369 (2010) et al.
- The size distribution of the Neptune Trojans and the missing intermediate-sized planetesimals. Astrophys. J. 723, L233–L237 (2010) &
- 71–87 (2008) , , & in The Solar System Beyond Neptune (eds , , , & ).
- 2012) Mercury: a Software Package for Orbital Dynamics (Astrophysics Source Code Library,
- An outer planet beyond Pluto and the origin of the trans-Neptunian belt architecture. Astron. J. 135, 1161–1200 (2008) &
- Terrestrial planet formation during the migration and resonance crossings of the giant planets. Astrophys. J. 773, 65 (2013) &
Extended data figures and tables
Extended Data Figures
- Extended Data Figure 1: Histogram of ω for minor planets with q > 30 au. (84 KB)
This is similar to Fig. 3 but in histogram form. The bodies with a > 150 au are shown as a black line (multiplied by a factor of ten for clarity) and bodies with a < 150 au are shown as a dotted line. The two distributions differ according to Kuiper’s test with a significance of 99.9%.
- Extended Data Figure 2: The ω cycling of 2012 VP113 in the current Solar System. (102 KB)
We note that over the course of 500 Myr, the argument of perihelion ω moves uniformly across all values. All inner Oort cloud Objects (Table 1) and other distant objects (Extended Data Table 2) are expected to exhibit this behaviour on differing timescales, so the observation that all are restricted to ω near 0° is inconsistent with the current dynamical environment in the Solar System. Because these are simulated plots, there are no error bars associated with data points.
- Extended Data Figure 3: The libration of ω for 2012 VP113 with an assumed object five times the mass of Earth at 210 au. (96 KB)
2012 VP113 librates about ω = 0° for most of the duration of the Solar System. This behaviour could explain why the two inner Oort cloud Objects (Table 1) and all objects with semi-major axes greater than 150 au and perihelia greater than Neptune’s (Extended Data Table 2) have ω ≈ 0°. The choice of mass and orbit of the perturber is not unique. Many possible distant planetary bodies can produce the pictured Kozai resonance behaviour, but the currently known Solar System bodies cannot. These are simulated plots, so there are no error bars associated with data points.