Interferometric Survey of Stellar Parameters: Mass of the metallic A-type binary β Aur
Abstract
Context. Long-baseline optical interferometry provides spatially resolved observations of close binaries, complementing spectroscopic and photometric constraints on stellar parameters. Aims. With the capabilities of the new visible CHARA/SPICA instrument and the multiple spectral band operation of CHARA, our goal is to resolve orbits of short-period binaries and develop a robust framework for combining interferometric, spectroscopic, and photometric observations into a single consistent model. Methods. For our target sample, we selected suitable binaries based on brightness, angular separation, and orbital properties based on the expected performance of the CHARA/SPICA instrument. As a case study, we analysed the bright eclipsing binary β Aurigae, composed of two slightly evolved A1 stars. We combined new interferometric observations of β Aur obtained with CHARA/SPICA, MIRC–X, and MYSTIC with archival MIRC data, radial velocities, and light curves. We first derived astrometric positions from interferometric observables and computed an orbital solution. Afterwards, we implemented a unified model, capable of tying interferometric modelling with the ellc code to simultaneously fit all observables using MCMC sampling. We performed a detailed analysis of the noise statistics of each data set and in the end we adopted a profile likelihood approach to account for underestimated noise and systematics. Results. We derived a consistent orbital and physical solution for β Aur through joint modelling. The inclusion of interferometric data tightly constrains the angular semi-major axis and inclination. Using profile likelihood to account for the different intrinsic levels of uncertainty of the fundamentally different observables, we derived the masses of the two stars, M 1 = 2.359 ± 0.005 M ⊙ and M 2 = 2.293 ± 0.004 M ⊙ , their radii R 1 = 2.752 ± 0.002 R ⊙ and R 2 = 2.622 ± 0.002 R ⊙ , and the distance to the binary, d = 24.30 ± 0.05 pc.
Versions
Related
- Interferometric Survey of Stellar Parameters: Limb darkening study with the Pipeline for Interferometric Measurements of Stars
- Interferometric Survey of Stellar Parameters: Limb darkening study with the "Pipeline for Interferometric Measurements of Stars
- Interferometric Survey of Stellar Parameters: Towards homogeneous FGK stars parameters and surface-brightness color relation in the context of PLATO space mission
- Double Trouble: How Unresolved Spectroscopic Binary Stars Skew GALAH DR4 Stellar Parameters
- Stellar Parameters and Magnetic Activity of Eruptive Variable Stars Based on TESS Light Curves and the LAMOST Spectral Survey
BibTeX
@article{jonak2026interferometric,
title = {{Interferometric Survey of Stellar Parameters: Mass of the metallic A-type binary β Aur}},
author = {J. Jonák and D. Mourard and J. Monnier and S. Hoin and M. Brož and A. Oplištilová and K. Kubiak and N. Ebrahimkutty and R. Ibañez-Bustos and H. Nowacki and M. Vrard and M. Bailleul and P. Bério and J. Dejonghe and R. Ligi and F. Morand and Nicolas Nardetto and D. Salabert and S. Deheuvels and A. Domiciano de Souza and A. Meilland and K. Perraut and M. Wittkowski and S. Kraus and N. Anugu and M. Gutierrez},
journal = {Astronomy \& Astrophysics - A\&A},
year = {2026},
month = sep,
doi = {10.1051/0004-6361/202661076},
eprint = {2609.03886},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05791665v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Interferometric Survey of Stellar Parameters: Mass of the metallic A-type binary β Aur
AU - J. Jonák
AU - D. Mourard
AU - J. Monnier
AU - S. Hoin
AU - M. Brož
AU - A. Oplištilová
AU - K. Kubiak
AU - N. Ebrahimkutty
AU - R. Ibañez-Bustos
AU - H. Nowacki
AU - M. Vrard
AU - M. Bailleul
AU - P. Bério
AU - J. Dejonghe
AU - R. Ligi
AU - F. Morand
AU - Nicolas Nardetto
AU - D. Salabert
AU - S. Deheuvels
AU - A. Domiciano de Souza
AU - A. Meilland
AU - K. Perraut
AU - M. Wittkowski
AU - S. Kraus
AU - N. Anugu
AU - M. Gutierrez
PY - 2026
DA - 2026/09/03
JO - Astronomy & Astrophysics - A&A
DO - 10.1051/0004-6361/202661076
UR - https://hal.science/hal-05791665v1
AB - Context. Long-baseline optical interferometry provides spatially resolved observations of close binaries, complementing spectroscopic and photometric constraints on stellar parameters. Aims. With the capabilities of the new visible CHARA/SPICA instrument and the multiple spectral band operation of CHARA, our goal is to resolve orbits of short-period binaries and develop a robust framework for combining interferometric, spectroscopic, and photometric observations into a single consistent model. Methods. For our target sample, we selected suitable binaries based on brightness, angular separation, and orbital properties based on the expected performance of the CHARA/SPICA instrument. As a case study, we analysed the bright eclipsing binary β Aurigae, composed of two slightly evolved A1 stars. We combined new interferometric observations of β Aur obtained with CHARA/SPICA, MIRC–X, and MYSTIC with archival MIRC data, radial velocities, and light curves. We first derived astrometric positions from interferometric observables and computed an orbital solution. Afterwards, we implemented a unified model, capable of tying interferometric modelling with the ellc code to simultaneously fit all observables using MCMC sampling. We performed a detailed analysis of the noise statistics of each data set and in the end we adopted a profile likelihood approach to account for underestimated noise and systematics. Results. We derived a consistent orbital and physical solution for β Aur through joint modelling. The inclusion of interferometric data tightly constrains the angular semi-major axis and inclination. Using profile likelihood to account for the different intrinsic levels of uncertainty of the fundamentally different observables, we derived the masses of the two stars, M 1 = 2.359 ± 0.005 M ⊙ and M 2 = 2.293 ± 0.004 M ⊙ , their radii R 1 = 2.752 ± 0.002 R ⊙ and R 2 = 2.622 ± 0.002 R ⊙ , and the distance to the binary, d = 24.30 ± 0.05 pc.
SN - 0004-6361
SN - 1432-0746
ER -