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--------------------- 2666 - PLANET NINE - beyond Pluto?
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- In 2014, astronomers suggested that a giant unseen "perturber" may lurk in the far outer solar system. This hypothesis is based on peculiarities in the orbits of the dwarf planet Sedna, and several other bodies beyond the orbit of Neptune.
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- In January 2016 astronomers found evidence that the orbits of additional trans-Neptune Objects, TNOs, had been discovered. Dubbed the hypothetical perturber "Planet Nine" they calculated that, if that world exists, it's likely about 10 times more massive than Earth and lies perhaps 600 astronomical units (AU) from the Sun.
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- (One AU is the average Earth-sun distance, about 93,000,000 miles.)
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- The existence of a roughly Neptune-mass Planet Nine could explain why the few known extreme trans-Neptunian objects seem to be clustered together in space.
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- Then, last summer 2019, astronomers found two new TNOs that Planet Nine may have tugged on, increasing the number of possibly affected bodies yet again.
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- Astronomers studied 22 "extreme" TNOs , which orbit the Sun at an average distance of at least 150 AU and never get closer than Neptune.
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- (Neptune lies 30 AU from the Sun and orbits on a roughly circular path.)
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- Specifically, they analyzed TNOs' "nodes," the two points at which the objects cross the plane of the solar system. Distant bodies such as these TNOs tend not to lie in the same plane as the Sun and the solar system's eight officially recognized planets.
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- The researchers found that the objects' nodes generally aggregate at certain distances from the Sun. As do some 24 "extreme Centaurs," very distant objects with some characteristics of asteroids and others of comets. In addition, they discovered a correlation between the nodes' positions and an orbital parameter known as inclination.
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- Assuming that the TNOs are dynamically similar to the comets that interact with Jupiter, we interpret these results as signs of the presence of a planet that is actively interacting with them in a range of distances from 300 to 400 AU.
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- The list of Pluto's neighbors just got considerably longer, potentially boosting scientists' odds of finding this Planet Nine.
Astronomers have discovered 139 more "minor planets", small bodies circling the Sun that are neither official planets nor comets, in the dark, frigid depths beyond Neptune's orbit, a new study reports. The new additions represent nearly 5% of the current TNO tally, which stands at about 3,000.
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- The scientists pored over data gathered by the Dark Energy Survey (DES) during its first four years of operation, from 2013 to 2017. The DES studies the heavens using the 520-megapixel Dark Energy Camera, which is mounted on the Blanco 4-meter telescope at the Observatory in Chile.
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- As the DES project's name implies, the main goal of the DES involves shedding light on dark energy, the mysterious force thought to be behind the universe's accelerating expansion. But the high-resolution DES imagery has a number of other applications, including the discovery of small objects in our own solar system.
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- The researchers started out with 7 billion DES-detected dots, which they whittled down to 22 million "transients" after ruling out objects such as galaxies that appeared in roughly the same spot on multiple nights. Those 22 million were further culled to 400 TNO candidates, whose movements the team was able to track over at least six different nights.
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- After months of vetting by analysis and observation, the team verified 316 of the small bodies as bona fide TNOs. These cataloged objects lie between 30 and 90 astronomical units (AU) from the Sun, and 139 of them are new to science, the researchers said.
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- (1 AU is the Earth-sun distance, which is about 93 million miles.)
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- The team is also running their analyses on the DES' entire six-year data set, an effort that could yield an additional 500 or so newfound TNOs. (The DES' initial run wrapped up in 2019.)
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- Such new additions could end up being bread crumbs that lead to Planet Nine. Planet Nine's existence is inferred from weird clustering in the orbits of certain TNOs.
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- Will Pluto ever be replaced with a real Planet Nine? Stay tuned, we still have a lot more to learn.
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- March 13, 2020 2666
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