Pushing the boundaries of asteroseismic individual frequency modelling: unveiling two evolved very-low metallicity red giants
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866909608389378048 |
|---|---|
| author | Larsen, Jens R. Rørsted, Jakob L. Børsen-Koch, Victor Aguirre Lundkvist, Mia S. Christensen-Dalsgaard, Jørgen Winther, Mark L. Stokholm, Amalie Li, Yaguang Slumstrup, Ditte Kjeldsen, Hans Corsaro, Enrico Benomar, Othman Dhanpal, Siddarth Weiss, Achim Mosser, Benoît Hekker, Saskia Stello, Dennis Korn, Andreas J. Jendreieck, Andressa Elsworth, Yvonne Handberg, Rasmus Kallinger, Thomas Jiang, Chen Ruchti, Greg |
| author_facet | Larsen, Jens R. Rørsted, Jakob L. Børsen-Koch, Victor Aguirre Lundkvist, Mia S. Christensen-Dalsgaard, Jørgen Winther, Mark L. Stokholm, Amalie Li, Yaguang Slumstrup, Ditte Kjeldsen, Hans Corsaro, Enrico Benomar, Othman Dhanpal, Siddarth Weiss, Achim Mosser, Benoît Hekker, Saskia Stello, Dennis Korn, Andreas J. Jendreieck, Andressa Elsworth, Yvonne Handberg, Rasmus Kallinger, Thomas Jiang, Chen Ruchti, Greg |
| contents | Metal-poor stars are key to understanding the first stellar generation in the Galaxy. Asteroseismic characterisation of red giants has traditionally relied on global seismic parameters, not the full spectrum of individual oscillation modes. Here, we present the first characterisation of two evolved very metal-poor stars, including the detailed mixed-mode patterns. We demonstrate that incorporating individual frequencies into grid-based modelling of red-giant stars enhances its precision, enabling detailed studies of these ancient stars and allowing us to infer the stellar properties of two $[\mathrm{Fe}/\mathrm{H}]{\sim}{-}2.5$ dex Kepler stars: KIC 4671239 and KIC 7693833. Recent developments in both observational and theoretical asteroseismology allows for detailed studies of the complex oscillation pattern of evolved giants. We employ Kepler time series and surface properties from high-resolution spectroscopic data to asteroseismically characterise the two stars using the BAyesian STellar Algorithm, BASTA. Both stars show agreement between constraints from seismic and classical observables; an overlap unrecoverable when purely considering the global seismic parameters. KIC 4671239 and KIC 7693833 were determined to have masses of $0.78^{+0.04}_{-0.03}$ and $0.83^{+0.03}_{-0.01} M_{\odot}$ with ages of $12.1^{+1.6}_{-1.5}$ and $10.3^{+0.6}_{-1.4}$ Gyr, respectively. A $\sim10$% discrepancy between observed and modelled $ν_{\mathrm{max}}$ suggests a metallicity dependence of its scaling relation, leading to overestimated masses and incorrect age inferences for metal-poor stars. Utilising the full spectrum of individual oscillation modes, we circumvent the dependence on the asteroseismic scaling relations, providing direct constraints on the stars themselves, pushing the boundaries of state-of-the-art detailed modelling of evolved stars at metallicities far different from solar. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_23063 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Pushing the boundaries of asteroseismic individual frequency modelling: unveiling two evolved very-low metallicity red giants Larsen, Jens R. Rørsted, Jakob L. Børsen-Koch, Victor Aguirre Lundkvist, Mia S. Christensen-Dalsgaard, Jørgen Winther, Mark L. Stokholm, Amalie Li, Yaguang Slumstrup, Ditte Kjeldsen, Hans Corsaro, Enrico Benomar, Othman Dhanpal, Siddarth Weiss, Achim Mosser, Benoît Hekker, Saskia Stello, Dennis Korn, Andreas J. Jendreieck, Andressa Elsworth, Yvonne Handberg, Rasmus Kallinger, Thomas Jiang, Chen Ruchti, Greg Solar and Stellar Astrophysics Metal-poor stars are key to understanding the first stellar generation in the Galaxy. Asteroseismic characterisation of red giants has traditionally relied on global seismic parameters, not the full spectrum of individual oscillation modes. Here, we present the first characterisation of two evolved very metal-poor stars, including the detailed mixed-mode patterns. We demonstrate that incorporating individual frequencies into grid-based modelling of red-giant stars enhances its precision, enabling detailed studies of these ancient stars and allowing us to infer the stellar properties of two $[\mathrm{Fe}/\mathrm{H}]{\sim}{-}2.5$ dex Kepler stars: KIC 4671239 and KIC 7693833. Recent developments in both observational and theoretical asteroseismology allows for detailed studies of the complex oscillation pattern of evolved giants. We employ Kepler time series and surface properties from high-resolution spectroscopic data to asteroseismically characterise the two stars using the BAyesian STellar Algorithm, BASTA. Both stars show agreement between constraints from seismic and classical observables; an overlap unrecoverable when purely considering the global seismic parameters. KIC 4671239 and KIC 7693833 were determined to have masses of $0.78^{+0.04}_{-0.03}$ and $0.83^{+0.03}_{-0.01} M_{\odot}$ with ages of $12.1^{+1.6}_{-1.5}$ and $10.3^{+0.6}_{-1.4}$ Gyr, respectively. A $\sim10$% discrepancy between observed and modelled $ν_{\mathrm{max}}$ suggests a metallicity dependence of its scaling relation, leading to overestimated masses and incorrect age inferences for metal-poor stars. Utilising the full spectrum of individual oscillation modes, we circumvent the dependence on the asteroseismic scaling relations, providing direct constraints on the stars themselves, pushing the boundaries of state-of-the-art detailed modelling of evolved stars at metallicities far different from solar. |
| title | Pushing the boundaries of asteroseismic individual frequency modelling: unveiling two evolved very-low metallicity red giants |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2503.23063 |