SPAMMS: 3D spectroscopic modeling of stellar surfaces
4 affiliations
- 1Instituto de Astrofísica de Canarias
- 2Departamento de Astrofísica, Universidad de La Laguna
- 3Institute of Astronomy
- 4Leuven Gravity Institute
Abstract
Context. Accurate modeling of stellar spectra is essential for deriving the physical properties of stars. However, traditional model atmospheres often oversimplify key phenomena – such as deformations due to rotation or multiplicity – that break spherical symmetry. The Spectroscopic PAtch Model for Massive Stars ( SPAMMS ) addresses these limitations by explicitly accounting for surface distortions, resulting in more realistic spectra for deformed stars. Yet, SPAMMS has been limited by the spectral types covered by its model atmosphere grids.
Aims. We aim to extend the parameter space of the stellar atmosphere grids available to the SPAMMS framework. By expanding the coverage of effective temperatures, surface gravities, and metallicities, we enable the synthesis of spectra across a broader range of spectral types.
Methods. We computed specific intensities, I ( λ, µ ), for 101 emergent angles using PRISMAS (Pipeline of Radiative Intensity Synthesis for Meshed Atmospheric Surfaces). Built upon SYNPLE , PRISMAS employs precomputed local thermodynamic equilibrium (LTE) and non-LTE model atmospheres, including two ATLAS9-Kurucz grids and the TLUSTY-based OSTAR2002 and BSTAR2006 models.
Results. The computed intensity grids span effective temperatures from 3500 to 55 000 K and surface gravities between 0.0 and 5.0 dex – covering the entire range of spectral types from O- to K-type stars. These grids also incorporate multiple metallicities (0−30 Z ⊙ ) and microturbulent velocities (1, 3, 5, 10km s ⁻¹ ), enabling detailed modeling of stars across diverse evolutionary stages. The spectral coverage extends from 3000 to 9000 Å, spanning both the ultraviolet and optical regimes with a sampling of ∆ λ = 0.01 A. As a proof of concept, we adopted the new intensity grids to model (i) a rapidly rotating B-type star, and (ii) an eclipsing Algol-type binary using SPAMMS .
Conclusions. The implementation of LTE-Kurucz and NLTE-TLUSTY model atmospheres significantly expands the parameter space accessible to SPAMMS . The code can now generate realistic synthetic spectra for a wide range of stellar types and geometries, including nonspherical and multiple systems. Therefore, by explicitly modeling three-dimensional surface effects, SPAMMS reproduces key observational signatures across a broad range of stellar masses and effective temperatures – from O- to K-type stars.
Related
- SPAMMS: 3D spectroscopic modeling of stellar surfaces. II. Implementation of Kurucz and TLUSTY model atmospheres
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- Photometric and Spectroscopic Study of Young Stellar Objects in IC 1848E Region
- Automated Detection of Double-Lined Spectroscopic Binaries in High-Resolution Spectra and a Probabilistic Analysis of Stellar Multiplicity
- From spectroscopic abundances to evolutionary [α/Fe] in stellar models
BibTeX
@article{galandieguez2026spamms,
title = {{SPAMMS: 3D spectroscopic modeling of stellar surfaces}},
author = {D. Galán-Diéguez and M. Abdul-Masih and C. Allende Prieto and S. R. Berlanas and A. Herrero and H. Sana},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = nov,
doi = {10.1051/0004-6361/202660234},
url = {https://www.aanda.org/10.1051/0004-6361/202660234},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - SPAMMS: 3D spectroscopic modeling of stellar surfaces
AU - D. Galán-Diéguez
AU - M. Abdul-Masih
AU - C. Allende Prieto
AU - S. R. Berlanas
AU - A. Herrero
AU - H. Sana
PY - 2026
DA - 2026/11/05
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202660234
UR - https://www.aanda.org/10.1051/0004-6361/202660234
AB - Context. Accurate modeling of stellar spectra is essential for deriving the physical properties of stars. However, traditional model atmospheres often oversimplify key phenomena – such as deformations due to rotation or multiplicity – that break spherical symmetry. The Spectroscopic PAtch Model for Massive Stars ( SPAMMS ) addresses these limitations by explicitly accounting for surface distortions, resulting in more realistic spectra for deformed stars. Yet, SPAMMS has been limited by the spectral types covered by its model atmosphere grids. Aims. We aim to extend the parameter space of the stellar atmosphere grids available to the SPAMMS framework. By expanding the coverage of effective temperatures, surface gravities, and metallicities, we enable the synthesis of spectra across a broader range of spectral types. Methods. We computed specific intensities, I ( λ, µ ), for 101 emergent angles using PRISMAS (Pipeline of Radiative Intensity Synthesis for Meshed Atmospheric Surfaces). Built upon SYNPLE , PRISMAS employs precomputed local thermodynamic equilibrium (LTE) and non-LTE model atmospheres, including two ATLAS9-Kurucz grids and the TLUSTY-based OSTAR2002 and BSTAR2006 models. Results. The computed intensity grids span effective temperatures from 3500 to 55 000 K and surface gravities between 0.0 and 5.0 dex – covering the entire range of spectral types from O- to K-type stars. These grids also incorporate multiple metallicities (0−30 Z ⊙ ) and microturbulent velocities (1, 3, 5, 10km s ⁻¹ ), enabling detailed modeling of stars across diverse evolutionary stages. The spectral coverage extends from 3000 to 9000 Å, spanning both the ultraviolet and optical regimes with a sampling of ∆ λ = 0.01 A. As a proof of concept, we adopted the new intensity grids to model (i) a rapidly rotating B-type star, and (ii) an eclipsing Algol-type binary using SPAMMS . Conclusions. The implementation of LTE-Kurucz and NLTE-TLUSTY model atmospheres significantly expands the parameter space accessible to SPAMMS . The code can now generate realistic synthetic spectra for a wide range of stellar types and geometries, including nonspherical and multiple systems. Therefore, by explicitly modeling three-dimensional surface effects, SPAMMS reproduces key observational signatures across a broad range of stellar masses and effective temperatures – from O- to K-type stars.
SN - 0004-6361
SN - 1432-0746
ER -