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Cosmic objects with strange orbits discovered beyond Neptune

Are they being tugged by Planet Nine?


A six-year search of space beyond the orbit of Neptune has netted 461 newly discovered objects.

These objects include four that are more than 230 astronomical units (AU) from the sun. (An astronomical unit is the distance from the Earth to the sun, about 93 million miles or 149.6 million kilometers). These extraordinarily distant objects might shed light on Planet Nine, a theoretical, never-observed body that might be hiding in deep space, its gravity affecting the orbits of some of the rocky objects at the solar system’s edge.

Red vs. Blue: Astronomers Nail Down the Origins of Rare Loner Dwarf Galaxies

The results provide a blueprint for finding such systems in the universe’s quieter, emptier regions.

By definition, dwarf galaxies are small and dim, with just a fraction of the stars found in the Milky Way and other galaxies. There are, however, giants among the dwarfs: Ultra-diffuse galaxies, or UDGs, are dwarf systems that contain relatively few stars but are scattered over vast regions. Because they are so diffuse, these systems are difficult to detect, though most have been found tucked within clusters of larger, brighter galaxies.

Now astronomers from MIT.

Magnetic Properties of Star-Forming Dense Cores — The Last Piece in the Puzzle of Star Formation

Magnetic fields in space are sometimes called the last piece in the puzzle of star formation. They are much harder to measure than the masses or motions of star-forming clouds, and their strength is still uncertain. If they are strong, they can deflect or even oppose gas flowing into a young stellar core as it collapses under the influence of gravity. If they are moderate in strength, however, they act more flexibly and guide the flow, but don’t prevent it.

Early measurements of field strengths in molecular clouds were based on radiation from molecules whose energy levels are sensitive to magnetic field strengths. Those data suggested the fields were of moderate strength, but those conclusions were tentative. More recent observations with stronger signals measured the polarized radiation from dust grains aligned with the magnetic field. These observations obtain the field strength from the changes in field direction across the cloud map.

CfA.

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