Chemical paradox in a binary system: Exploring metal enrichment in HD 81809B
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , |
|---|---|
| Format: | Preprint |
| Publié: |
2026
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866914616283496448 |
|---|---|
| author | Moedas, Nuno Di Mauro, Maria Pia |
| author_facet | Moedas, Nuno Di Mauro, Maria Pia |
| contents | The HD 81809 system presents peculiar chemical composition with a large metallicity difference between its two components: the primary has low metallicity ([Fe/H]=-0.57 dex), while the secondary has approximately solar metallicity ([Fe/H]=0.0 dex). This study investigates whether the chemical enrichment of HD 81809B can be reconciled by a planetary engulfment event, consistent with the star's evolutionary constraints. Using Modules for Experiments in Stellar Astrophysics (MESA) code, we model HD 81809B introducing accretion events with different ranges of masses and chemical mixtures to understand their impact in the surface chemical composition. Our simulation shows that reproducing the observed surface [Fe/H] in HD 81809B requires a substantial accretion event. To reach the observed metallicity, the star must engulf 25 to 75 $M_\oplus$ of metals near its current age. Accretion brings the effective temperature of stellar models closer to the observed one; however, the lithium results over-enriched. In order to reproduce the abundance of this element, the star must accrete less than 6 $M_\oplus$. These results suggest that a planetary accretion event is plausible in the evolution of HD 81809B; however, the chemical composition of the accreted material may differ from the assumptions adopted here. Nevertheless, this study emphasizes the importance of considering such external events when modeling chemically anomalous binary systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_31060 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Chemical paradox in a binary system: Exploring metal enrichment in HD 81809B Moedas, Nuno Di Mauro, Maria Pia Solar and Stellar Astrophysics Earth and Planetary Astrophysics The HD 81809 system presents peculiar chemical composition with a large metallicity difference between its two components: the primary has low metallicity ([Fe/H]=-0.57 dex), while the secondary has approximately solar metallicity ([Fe/H]=0.0 dex). This study investigates whether the chemical enrichment of HD 81809B can be reconciled by a planetary engulfment event, consistent with the star's evolutionary constraints. Using Modules for Experiments in Stellar Astrophysics (MESA) code, we model HD 81809B introducing accretion events with different ranges of masses and chemical mixtures to understand their impact in the surface chemical composition. Our simulation shows that reproducing the observed surface [Fe/H] in HD 81809B requires a substantial accretion event. To reach the observed metallicity, the star must engulf 25 to 75 $M_\oplus$ of metals near its current age. Accretion brings the effective temperature of stellar models closer to the observed one; however, the lithium results over-enriched. In order to reproduce the abundance of this element, the star must accrete less than 6 $M_\oplus$. These results suggest that a planetary accretion event is plausible in the evolution of HD 81809B; however, the chemical composition of the accreted material may differ from the assumptions adopted here. Nevertheless, this study emphasizes the importance of considering such external events when modeling chemically anomalous binary systems. |
| title | Chemical paradox in a binary system: Exploring metal enrichment in HD 81809B |
| topic | Solar and Stellar Astrophysics Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2605.31060 |