A Solar System formation analogue in the Ophiuchus star-forming complex

Anomalies among the daughter nuclei of the extinct short-lived radionuclides in calcium–aluminium-rich inclusions indicate that the Solar System must have been born near a source of the short-lived radionuclides so that they could be incorporated before they decayed away1. γ-rays from one such living short-lived radionuclide, 26Al, are detected in only a few nearby star-forming regions. Here we employ multiwavelength observations to demonstrate that one such region, Ophiuchus, containing many prestellar cores that may serve as analogues for the emerging Solar System2, is inundated with 26Al from the neighbouring Upper Scorpius association3, and so may provide concrete guidance for how short-lived radionuclide enrichment proceeded in the Solar System, complementary to the meteoritics. We demonstrate via Bayesian forward modelling drawing on a wide range of observational and theoretical results that this 26Al probably (1) arises from supernova explosions, (2) arises from multiple stars, (3) has enriched the gas before the formation of the cores and (4) gives rise to a broad distribution of core enrichment spanning about two orders of magnitude. This means that if the spread in calcium–aluminium-rich inclusion ages is small, as it is in the Solar System, protoplanetary disks must suffer a global heating event. The nearby Ophiuchus star-forming region should be able to give us insight into the incorporation of short-lived radionuclides into the early Solar System. These radionuclides, such as 26Al, originated from multiple sources and gently warmed the protosolar disk over an extended period. Another heating event, therefore—perhaps an FU Orionis-type outburst—presumably led to the resetting of the radiogenic clock.