近日，美国西南研究院的Harold F. Levison及其研究团队取得一项新进展。经过不懈努力，他们发现Dinkinesh小行星(152830)的一颗接触双星。相关研究成果已于2024年5月29日在国际权威学术期刊《自然》上发表。

该研究团队报道了露西号宇宙飞船在距离Dinkinesh431公里处经过时的观测结果。露西发现，有效直径只有720米的Dinkinesh出乎意料地复杂。特别值得注意的是，其存在一个明显的纵向槽，它横跨在巨大的赤道脊上。此外，他们还确认了第一颗接触双星，并将其命名为(152830)Dinkinesh I Selam。Selam由两个直径相近的瓣组成，分别为210米和230米。它沿着距离Dinkinesh 3.1公里的轨道运行，轨道周期约为52.7小时，并呈现出潮汐锁定的状态。

基于系统的动力状态、角动量以及地貌观测，研究人员推测Dinkinesh的山脊和槽可能是由YORP效应引起的自旋上升导致的质量破坏，随后是脱落物质的部分再聚集。而Selam很可能就是这次事件产生的物质聚集而成的。

据悉，直径小于5公里的小行星具有复杂的历史，因为它们足够小，辐射扭矩(即YORP, Yarkovsky-O 'Keefe-Radzievskii-Paddack效应的缩写)在它们的演化中是一个值得注意的因素。(152830) Dinkinesh是一颗绕太阳运行的小行星，靠近主小行星带的内缘，以日心为中心的半长轴为2.19AU;它的S型光谱是主带这部分天体的典型特征。

附：英文原文

Title: A contact binary satellite of the asteroid (152830) Dinkinesh

Author: Levison, Harold F., Marchi, Simone, Noll, Keith S., Spencer, John R., Statler, Thomas S., Bell, James F., Bierhaus, Edward B., Binzel, Richard, Bottke, William F., Britt, Daniel, Brown, Michael E., Buie, Marc W., Christensen, Philip R., Dello Russo, Neil, Emery, Joshua P., Grundy, William M., Hahn, Matthias, Hamilton, Victoria E., Howett, Carly, Kaplan, Hannah, Kretke, Katherine, Lauer, Tod R., Manzoni, Claudia, Marschall, Raphael, Martin, Audrey C., May, Brian H., Mottola, Stefano, Olkin, Catherine B., Ptzold, Martin, Parker, Joel Wm., Porter, Simon, Preusker, Frank, Protopapa, Silvia, Reuter, Dennis C., Robbins, Stuart J., Salmon, Julien, Simon, Amy A., Stern, S. Alan, Sunshine, Jessica M., Wong, Ian, Weaver, Harold A., Adam, Coralie, Ancheta, Shanti, Andrews, John, Anwar, Saadat, Barnouin, Olivier S., Beasley, Matthew, Berry, Kevin E., Birath, Emma, Bolin, Bryce, Booco, Mark, Burns, Rich, Campbell, Pam, Carpenter, Russell, Crombie, Katherine, Effertz, Mark, Eifert, Emily, Ellis, Caroline, Faiks, Preston, Fischetti, Joel, Fleming, Paul, Francis, Kristen, Franco, Ray, Freund, Sandy, Gallagher, Claire, Geeraert, Jeroen, Gobat, Caden, Gorgas, Donovan, Granat, Chris, Gray, Sheila, Haas, Patrick, Harch, Ann, Hegedus, Katie, Isabelle, Chris

Issue&Volume: 2024-05-29

Abstract: Asteroids with diameters less than about 5km have complex histories because they are small enough for radiative torques (that is, YORP, short for the Yarkovsky–O’Keefe–Radzievskii–Paddack effect) to be a notable factor in their evolution. (152830) Dinkinesh is a small asteroid orbiting the Sun near the inner edge of the main asteroid belt with a heliocentric semimajor axis of 2.19AU; its S-type spectrum is typical of bodies in this part of the main belt. Here we report observations by the Lucy spacecraft as it passed within 431km of Dinkinesh. Lucy revealed Dinkinesh, which has an effective diameter of only 720m, to be unexpectedly complex. Of particular note is the presence of a prominent longitudinal trough overlain by a substantial equatorial ridge and the discovery of the first confirmed contact binary satellite, now named (152830) Dinkinesh I Selam. Selam consists of two near-equal-sized lobes with diameters of 210m and 230m. It orbits Dinkinesh at a distance of 3.1km with an orbital period of about 52.7h and is tidally locked. The dynamical state, angular momentum and geomorphologic observations of the system lead us to infer that the ridge and trough of Dinkinesh are probably the result of mass failure resulting from spin-up by YORP followed by the partial reaccretion of the shed material. Selam probably accreted from material shed by this event.

DOI: 10.1038/s41586-024-07378-0

Source: https://www.nature.com/articles/s41586-024-07378-0