The Sun’s Birth Environment

Author(s): Steve Desch, Núria Miret-Roig
Abstract: Meteorites trace planet formation in the Sun’s protoplanetary disk, but they also record the influence of the Sun’s birth environment. Whether the Sun formed in a region like Taurus-Auriga with ∼10² stars, or a region like the Carina Nebula with ∼10⁶ stars, matters for how large the Sun’s disk was, for how long and from how far away it accreted gas from the molecular cloud, and how it acquired radionuclides like ²⁶Al. To provide context for the interpretation of meteoritic data, we review what is known about the Sun’s birth environment. Based on an inferred gas disk outer radius ≈50−90 AU, radial transport in the disk, and the abundances of noble gases in Jupiter’s atmosphere, the Sun’s molecular cloud and protoplanetary disk were exposed to an ultraviolet flux G₀∼30−3000 during its birth and first ≈10 Myr of evolution. Based on the orbits of Kuiper Belt objects, the Solar System was subsequently exposed to a stellar density ≈100M_⊙pc⁻³ for ≈100 Myr, strongly implying formation in a bound cluster. These facts suggest formation in a region like the outskirts of the Orion Nebula, perhaps 2 pc from the center. The protoplanetary disk might have accreted gas for many Myr, but a few ×10⁵ yr seems more likely. It probably inherited radionuclides from its molecular cloud, enriched by inputs from supernovae and especially Wolf-Rayet star winds, and acquired a typical amount of ²⁶Al.
Organisation(s): Department of Astrophysics
External organisation(s): Arizona State University
Journal: Space Science Reviews
Volume: 220
No. of pages: 20
ISSN: 0038-6308
DOI: https://doi.org/10.1007/s11214-024-01113-x
Publication date: 10-2024
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/7913a6e5-af4e-4a30-ad7c-06ce4771bb1a

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