Ammonite. They are lousy news for the fans of the planet nine

In the Dark confines From the Solar System, beyond the orbit of Neptune, a new world has appeared. First detected in May 2023 from the top of the Mauna Kea volcano in Hawaii, astronomers have just called a name: ammonite. But not everything is good news, especially For those who hoped to find The planet nine.

Short. 2023 KQ14 “Ammonite” is a new transneptunian object between 220 and 380 km in diameter that revolves around the sun in an extremely wide elliptical orbit. The peculiar of his orbit is that he is not aligned with other similar objects. According to a study Posted in Nature Astronomythe finding challenges the hypothesis that a distant planet still to discover (the elusive planet nine) could be aligning its orbits.

A true cosmic fossil. The Amonite nickname, like ancient marine fossils, is not accidental. Astronomers believe that this object is a solar system relic, a time capsule whose orbit has remained virtually unchanged for 4.5 billion years.

In fact, its discovery was possible thanks to the Fossil II Project (Formation of the Outer Solar System: An iory legacy), which tracked this type of objects with the Subaru telescope in Hawaii. What they found exceeded their expectations, because Ammonite is quite special.

A very exclusive club. In addition to having a considerable size, Ammonite is far away. It has the third most distant perihelio ever detected: the point closest to the sun of its orbit is 66 astronomical units, more than double that of Neptune. The interesting thing is that what astronomers occupy the “perihelium gap”, an area between 50 and 75, where they had not found objects of this type.

Ammonite is what is known as a senoid, an ultra -exclusive category of transneptunian objects of which we only knew three specimens: Sedna (The candidate for dwarf planet that gives name to the group), 2012 VP113 and Leleākūhonua. What makes them so special is that their orbits are enormous and extremely elliptical, but its closest point to the sun is so far that Neptune’s gravity barely affects them. They are gravitationally isolated.

Problems for the planet nine. For years, The planet’s hypothesis nine He has won traction to explain a strange anomaly: the orbits of the sedoids and other extreme transneptunian objects They seem to be groupedas if the severity of a massive planet, too dark to be easily detected from Earth, were directing them.

In addition to dark and distant, we now have another complication that makes it difficult to find. Amonite’s orbit is not only aligned with that of the other three senoids, but points in the opposite direction. With most of the models proposed for planet nine, Ammonite’s orbit would be unstable: it would have been expelled from the solar system a long time ago.

So what happened? If it is not the planet nine, what molded those strange orbits? By simulating the orbits of the four senoids known back in time, Synica Academy researchers They discovered something. Although today they are scattered, simulations show with more than 97% confidence that about 4.2 billion years ago, their perihelios were grouped.

This suggests that a cataclysmic event occurred about 300 million years after the formation of the solar system placed them all in their strange trajectories. But what was that power so powerful?

There are two great candidates. The near passage of a wandering star who approached our sun in his childhood and that could have gravitationally scrambled the confines of the system. Or the existence of a giant planet that, after interacting with these objects, was subsequently expelled from the solar system. Not a planet nine, but a rebel planet.

Image | Synical Academy

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