Nova Explosions in 2040

Novae are thermonuclear explosions on the surface of accreting white dwarfs and are key laboratories for studying explosive nucleosynthesis, particle acceleration, shock physics, and binary evolution. Despite major progress driven by wide-field time-domain surveys and multi-wavelength facilities, our understanding of nova explosions remains limited by incomplete temporal coverage, heterogeneous spectroscopic follow-up, and poorly constrained ejecta properties. In this white paper we outline the open scientific questions that will define nova research in the 2040s, focusing on the mass, composition, geometry, and dynamics of the ejecta, the role of the underlying binary system, and the connection between nuclear burning, shocks, and emission across the electromagnetic spectrum. We argue that decisive progress requires rapid-response, high-cadence, multi-wavelength observations, anchored by systematic high-resolution optical and near-infrared spectroscopy from eruption to quiescence. Finally, we identify key technological requirements needed to enable transformative advances in the physics of nova explosions over the coming decades.

💡 Research Summary

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The white paper “Nova Explosions in 2040” presents a forward‑looking roadmap for the study of classical novae—thermonuclear eruptions on the surface of accreting white dwarfs—through the coming decade. It begins by emphasizing the unique role of novae as natural laboratories for explosive nucleosynthesis, particle acceleration to TeV energies, shock physics, and binary evolution. Despite the wealth of data gathered by wide‑field time‑domain surveys (e.g., ZTF, ASAS‑SN, LSST) and multi‑wavelength facilities, the authors argue that our understanding remains hampered by three inter‑related deficiencies: (1) incomplete temporal coverage, especially during the crucial early rise and the long decline to quiescence; (2) heterogeneous and often low‑resolution spectroscopic follow‑up; and (3) poorly constrained ejecta properties such as mass, composition, geometry, and clumpiness.

The paper identifies four overarching scientific questions for the 2040s:

1. Mass and Composition of the Ejecta – Accurate ejecta masses are limited by uncertainties in distance (few Gaia parallaxes, rare light‑echo measurements), interstellar extinction (most novae lie in the Galactic plane), and ejecta clumpiness. The authors call for simultaneous coverage of the full optical–near‑IR window (300–2400 nm) at a spectral resolving power R ≥ 50 000 to derive reliable elemental abundances and to probe clumping via diagnostics such as the