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- Cumming, Graeme S., et al.
(författare)
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Research priorities for the sustainability of coral-rich western Pacific seascapes
- 2023
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Ingår i: Regional Environmental Change. - 1436-3798 .- 1436-378X. ; 23:2
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Tidskriftsartikel (refereegranskat)abstract
- Nearly a billion people depend on tropical seascapes. The need to ensure sustainable use of these vital areas is recognised, as one of 17 policy commitments made by world leaders, in Sustainable Development Goal (SDG) 14 (‘Life below Water’) of the United Nations. SDG 14 seeks to secure marine sustainability by 2030. In a time of increasing social-ecological unpredictability and risk, scientists and policymakers working towards SDG 14 in the Asia–Pacific region need to know: (1) How are seascapes changing? (2) What can global society do about these changes? and (3) How can science and society together achieve sustainable seascape futures? Through a horizon scan, we identified nine emerging research priorities that clarify potential research contributions to marine sustainability in locations with high coral reef abundance. They include research on seascape geological and biological evolution and adaptation; elucidating drivers and mechanisms of change; understanding how seascape functions and services are produced, and how people depend on them; costs, benefits, and trade-offs to people in changing seascapes; improving seascape technologies and practices; learning to govern and manage seascapes for all; sustainable use, justice, and human well-being; bridging communities and epistemologies for innovative, equitable, and scale-crossing solutions; and informing resilient seascape futures through modelling and synthesis. Researchers can contribute to the sustainability of tropical seascapes by co-developing transdisciplinary understandings of people and ecosystems, emphasising the importance of equity and justice, and improving knowledge of key cross-scale and cross-level processes, feedbacks, and thresholds.
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- Hosseinzadeh, Griffin, et al.
(författare)
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The Early Light Curve of SN 2023bee : Constraining Type Ia Supernova Progenitors the Apian Way
- 2023
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Ingår i: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 953:1
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Tidskriftsartikel (refereegranskat)abstract
- We present very early photometric and spectroscopic observations of the Type Ia supernova (SN Ia) 2023bee, starting about 8 hr after the explosion, which reveal a strong excess in the optical and nearest UV (U and UVW1) bands during the first several days of explosion. This data set allows us to probe the nature of the binary companion of the exploding white dwarf and the conditions leading to its ignition. We find a good match to the Kasen model in which a main-sequence companion star stings the ejecta with a shock as they buzz past. Models of double detonations, shells of radioactive nickel near the surface, interaction with circumstellar material, and pulsational delayed detonations do not provide good matches to our light curves. We also observe signatures of unburned material, in the form of carbon absorption, in our earliest spectra. Our radio nondetections place a limit on the mass-loss rate from the putative companion that rules out a red giant but allows a main-sequence star. We discuss our results in the context of other similar SNe Ia in the literature.
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- Villanueva, G. L., et al.
(författare)
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JWST molecular mapping and characterization of Enceladus’ water plume feeding its torus
- 2023
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Ingår i: Nature Astronomy. - : Springer Nature. - 2397-3366. ; 7:9, s. 1056-1062
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Tidskriftsartikel (refereegranskat)abstract
- Enceladus is a prime target in the search for life in our Solar System, having an active plume that is likely to be connected to a large liquid water sub-surface ocean. Using the sensitive near-infrared spectograph instrument on board the James Webb Space Telescope, we searched for organic compounds and characterized the plume’s composition and structure. The observations directly sample the fluorescence emissions of H2O and reveal an extraordinarily extensive plume (up to 10,000 km or 40 Enceladus radii) at cryogenic temperatures (25 K) embedded in a large bath of emission originating from Enceladus’ torus. Intriguingly, the observed outgassing rate (300 kg s−1) is similar to that derived from close-up observations with Cassini 15 years ago, and the torus density is consistent with previous spatially unresolved measurements with Herschel 13 years ago, which indicates that the vigour of gas eruption from Enceladus has been relatively stable over decadal timescales. This level of activity is sufficient to maintain a derived column density of 4.5 × 1017 m−2 for the embedding equatorial torus, and establishes Enceladus as the prime source of water across the Saturnian system. We performed searches for several non-water gases (CO2, CO, CH4, C2H6, CH3OH), but none were identified in the spectra. On the surface of the trailing hemisphere, we observe strong H2O ice features, including its crystalline form, yet we do not recover CO2, CO or NH3 ice signatures from these observations. As we prepare to send new spacecraft into the outer Solar System, these observations demonstrate the unique ability of the James Webb Space Telescope to provide critical support for the exploration of distant icy bodies and cryovolcanic plumes.
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