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| Main Authors: | , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2411.05314 |
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| _version_ | 1866912110918762496 |
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| author | Nordlander, T. Baratella, M. Spina, L. D'Orazi, V. |
| author_facet | Nordlander, T. Baratella, M. Spina, L. D'Orazi, V. |
| contents | Spectroscopic analyses of young late-type stars suffer from systematic inaccuracies, typically under-estimating metallicities but over-estimating abundances of certain elements including oxygen and barium. Effects are stronger in younger and cooler stars, and recent evidence specifically indicates a connection to the level of chromospheric activity. We present here a two-component spectroscopic model representing a non-magnetic baseline plus a magnetic spot, and analyse the resulting synthetic spectra of young solar analogues using a standard spectroscopic technique. For a moderately active star with solar parameters and chromospheric activity index log R'_HK = -4.3 (~100 Myr), we predict that [Fe/H] is underestimated by 0.06 dex while v_mic is overestimated by 0.2 km/s; for higher activity levels we predict effects as large as 0.2 dex and 0.7 km/s. Predictions are in agreement with literature data on solar twins, and indicate that the model is a plausible explanation to the observed effects. The model is simple enough that it can be included in spectroscopic packages with only changes to the underlying spectrum synthesis modules, if a log R'_HK value is provided. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_05314 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | A simple model for spectroscopic analyses of active stars Nordlander, T. Baratella, M. Spina, L. D'Orazi, V. Solar and Stellar Astrophysics Spectroscopic analyses of young late-type stars suffer from systematic inaccuracies, typically under-estimating metallicities but over-estimating abundances of certain elements including oxygen and barium. Effects are stronger in younger and cooler stars, and recent evidence specifically indicates a connection to the level of chromospheric activity. We present here a two-component spectroscopic model representing a non-magnetic baseline plus a magnetic spot, and analyse the resulting synthetic spectra of young solar analogues using a standard spectroscopic technique. For a moderately active star with solar parameters and chromospheric activity index log R'_HK = -4.3 (~100 Myr), we predict that [Fe/H] is underestimated by 0.06 dex while v_mic is overestimated by 0.2 km/s; for higher activity levels we predict effects as large as 0.2 dex and 0.7 km/s. Predictions are in agreement with literature data on solar twins, and indicate that the model is a plausible explanation to the observed effects. The model is simple enough that it can be included in spectroscopic packages with only changes to the underlying spectrum synthesis modules, if a log R'_HK value is provided. |
| title | A simple model for spectroscopic analyses of active stars |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2411.05314 |