Issue |
A&A
Volume 694, February 2025
|
|
---|---|---|
Article Number | A238 | |
Number of page(s) | 13 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202453400 | |
Published online | 18 February 2025 |
MUSE observations of V1425 Aql reveal an arc-shaped nova shell
1
Instituto de Física y Astronomía, Universidad de Valparaíso,
Valparaíso,
Chile
2
European Southern Observatory, Casilla 19001,
Santiago 19,
Chile
★ Corresponding author; lientur.celedon@postgrado.uv.cl
Received:
11
December
2024
Accepted:
15
January
2025
Context. Nova shells are the remnants of a nova eruption in a cataclysmic variable system. By studying their geometry we can better understand the physical mechanisms that shape such shells during the nova eruption. A nova shell that challenges our current understanding of these processes is the shell observed around V1425 Aql. It has at least two different components: an inner, symmetric shell and an outer, asymmetric shell, with the latter expanding faster than the former. The physical reason for the asymmetric ejecta is not clear.
Aims. We aim to characterise the properties of and differences between these two components to understand the origin of the unusual shape.
Methods. We acquired MUSE data to study the spatial position and kinematics of the expanding gas across the shell. Our analysis involved channel maps, position-velocity diagrams, and the reconstruction of the 3D geometry of the nova shell.
Results. Several emission lines are detected within the MUSE wavelength coverage, including but not limited to Balmer, oxygen, nitrogen, and helium lines. There are significant differences in the spectra of the inner and outer shells, with the latter being observed only in forbidden transitions, and the former in a mix of forbidden and allowed ones. Our analysis reveals that the outer shell has a geometry consistent with an arc-shaped structure that partially encircles the more spherical inner shell. Within the inner shell, clumpy structures start to be noticeable in the lines of Hα+[N II].
Conclusions. We have constrained the geometry of the outer shell to an arc-shaped structure, although the physical reason for its origin still eludes us. Further monitoring of the evolution of both shells of this object might help clarify the mechanism behind this unusual configuration.
Key words: techniques: imaging spectroscopy / novae, cataclysmic variables / ISM: jets and outflows
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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