近日，意大利天体物理学和行星学研究所
据研究人员介绍，谷神星拥有显著较高的脂肪族有机浓度，比表面积从大约5%到＞30%重量不等。由于谷神星轨道上强烈的脂肪族有机特征和辐射水平，这些有机物的起源和持久性存在争议，这通常会导致它们被破坏，阻碍探测。
为了调查这一点，研究人员在室内进行实验，以复制富有机质地区的特征如何因辐射而降解。结果发现降解速度很快，这意味着在过去的几百万年里，被掩埋的有机物暴露了出来。这种降解率，加上观察到的数量，表明脂肪族在浅层地下可能大量存在。研究估计，最初的脂肪族丰度是目前观察到的2到30倍，大大超过了在碳质球粒陨石中发现的水平，表明它们要么浓度很高，要么纯度很高。
附：英文原文
Title: Recent replenishment of aliphatic organics on Ceres from a large subsurface reservoir
Author: Maria Cristina De Sanctis, Giuseppe A. Baratta, John R. Brucato, Julie Castillo-Rogez, Mauro Ciarniello, Fabio Cozzolino, Simone De Angelis, Marco Ferrari, Daniele Fulvio, Massimo Germanà, Vito Mennella, Silvia Pagnoscin, Maria Elisabetta Palumbo, Giovanni Poggiali, Ciprian Popa, Andrea Raponi, Carlotta Scirè, Giovanni Strazzulla, Riccardo Giovanni Urso
Issue&Volume: 2024-09-25
Abstract: Ceres hosts notable aliphatic-organic concentrations, ranging from approximately 5 to >30 weight % in specific surface areas. The origins and persistence of these organics are under debate due to the intense aliphatic organic signature and radiation levels in Ceres’ orbit, which would typically lead to their destruction, hindering detection. To investigate this, we conducted laboratory experiments to replicate how the signature of the organic-rich regions would degrade due to radiation. Our findings indicate a fast degradation rate, implying the exposure of buried organics within the past few million years. This degradation rate, coupled with observed quantities, implies that the aliphatics must be present in substantial quantities within the shallow subsurface. Our estimates suggest an initial aliphatic abundance 2 to 30 times greater than currently observed, surpassing significantly the levels found in carbonaceous chondrites, indicating either a significant concentration or remarkable purity.
DOI: adp3664
