Researchers solve colorful Kuiper Belt puzzle

The Kuiper Belt is an enormous disk of icy our bodies, together with Pluto, that’s situated simply exterior of Neptune’s orbit in our solar system. Objects noticed within the Kuiper Belt exhibit a extra diversified shade vary than some other solar system inhabitants, with colours starting from white to darkish reddish. Whereas the supply of this range in colours is unknown, scientists have speculated that it’s possible the results of the extended publicity to radiation of natural supplies by galactic cosmic rays.

A brand new examine led by researchers in College of Hawaiʻi at Mānoa’s Division of Chemistry has replicated the setting within the Kuiper Belt to find what’s inflicting the array of colours in hydrocarbon-rich surfaces of Kuiper Belt objects, offering an answer to a long-standing downside in astrophysics. The examine was printed in Science Advances on Might 31.

The analysis crew led by Professor Ralf I. Kaiser carried out the cutting-edge analysis at UH Mānoa. They used ultra-high vacuum irradiation experiments and performed complete analyses to look at the colour evolution and its supply on the molecular degree, as galactic cosmic rays processed hydrocarbons, comparable to methane and acetylene, underneath Kuiper Belt-like circumstances.

Fragrant (natural molecules with fused benzene rings) structural items carrying as much as three rings, for instance within the chemical compounds phenanthrene, phenalene and acenaphthylene, linked by hydrogen-deficient bridges amongst one another, had been discovered to play a key position in producing reddish colours. The UH experiments demonstrated the extent of molecular complexity of galactic cosmic rays processing hydrocarbons and offered perception into the position performed by ices uncovered to radiation within the early manufacturing of organic precursor molecules, molecules that take part in a chemical response that produces one other molecule.

“This analysis is a essential first step to systematically unravel the carriers of the molecular items liable for hydrocarbon-rich surfaces of Kuiper Belt objects,” Kaiser mentioned. “Since astronomical detections additionally detected, e.g., ammonia, water, and methanol, on the surfaces of Kuiper Belt objects, additional experiments on the cosmic ray processing of those ices hopefully reveal the character of the true shade range of Kuiper Belt objects on the molecular degree.”

The analysis crew consisted of Ralf I. Kaiser, Chaojiang Zhang, Cheng Zhu, Andrew M. Turner and Ivan O. Antonov from UH Mānoa; Adrien D. Garcia and Cornelia Meinert from Côte d’Azur College in France; Leslie A. Younger from the Southwest Analysis Institute in Colorado; and David C. Jewitt from UCLA, who beforehand labored at UH’s Institute for Astronomy.