Sweet news! 😊 Amazing stuff! Mind boggling!
Why the heck the PNAS does not mention the distance of this object is mysterious! I had to research it myself!
How realistic was this simulation? How strong were the assumptions?
"Observations from the New Horizons spacecraft detected methanol ice and a reddish coloration on the surface of Arrokoth, the furthest Kuiper Belt object (KBO) visited by a spacecraft. The source of Arrokoth’s distinctive red coloration is unclear. Chaojiang Zhang et al. simulated the exposure of methanol and carbon monoxide ices to proxies for galactic cosmic rays in the lab to explore the origins of Arrokoth’s colors. The authors used energetic electrons to replicate the equivalent radiation dose of exposure to galactic cosmic rays for approximately 1.8 billion years at temperatures below 40 K. Spectroscopic analyses, two-dimensional gas chromatography, and time-of-flight mass spectrometry helped characterize the resulting organic molecules and colors. The lab experiment replicated the red coloration of Arrokoth. The results suggest that the surface of Arrokoth is rich in sugars, including ribose and glucose, some of which are molecular building blocks for RNA and lipids. Complex organic compounds, such as polycyclic aromatic hydrocarbons, were key contributors to the red coloration. According to the authors, “sugar worlds,” such as Arrokoth and similar KBOs, are a plausible prebiotic source for organic molecules important to the evolution of life, which could subsequently have been delivered to Earth by comets. ..."
From the significance and abstract:
"Significance
The flyby of the New Horizons spacecraft of the Kuiper Belt Object Arrokoth revealed its reddish appearance and unraveled the unexpected presence of a methanol-rich surface. However, the chemical compositions and fundamental processes responsible for the surface coloring have remained ambiguous. Here, we have evidence that methanol ices exposed to galactic cosmic rays can replicate the colors of Arrokoth. Organics formed indicate that Arrokoth is rich in sugars including biologically significant ribose and glucose, while aromatic hydrocarbons are essential in producing the ultrared color slopes. Our findings provide insights into the surface evolution of planetesimals in the early Solar System ranging from the Kuiper Belt to Oort’s clouds as repositories of short and long-periodic comets.
Abstract
The Kuiper Belt object (KBO) Arrokoth, the farthest object in the Solar System ever visited by a spacecraft, possesses a distinctive reddish surface and is characterized by pronounced spectroscopic features associated with methanol. However, the fundamental processes by which methanol ices are converted into reddish, complex organic molecules on Arrokoth’s surface have remained elusive. Here, we combine laboratory simulation experiments with a spectroscopic characterization of methanol ices exposed to proxies of galactic cosmic rays (GCRs). Our findings reveal that the surface exposure of methanol ices at 40 K can replicate the color slopes of Arrokoth. Sugars and their derivatives (acids, alcohols) with up to six carbon atoms, including glucose and ribose—fundamental building block of RNA—were ubiquitously identified. In addition, polycyclic aromatic hydrocarbons (PAHs) with up to six ring units (13C22H12) were also observed. These sugars and their derivatives along with PAHs connected by unsaturated linkers represent key molecules rationalizing the reddish appearance of Arrokoth. The formation of abundant sugar-related molecules dubs Arrokoth as a sugar world and provides a plausible abiotic preparation route for a key class of biorelevant molecules on the surface of KBOs prior to their delivery to prebiotic Earth."
P.S. "Arrokoth was named for a word in the Powhatan language of the Tidewater region of Virginia and Maryland in the eastern United States. The Powhatan language became extinct in the late 18th century and little was recorded of it." (Wikipedia)
Ionizing radiation exposure on Arrokoth shapes a sugar world (no public access)
Grayscale composite image of Arrokoth
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