The role of carbon in red giant spectro-seismology

Fuente: arXiv
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Autores principales: Banks, Kirsten A., Martell, Sarah L., Tinney, C. G., Stello, Dennis, Hon, Marc, Reyes, Claudia, Priest, James, Buder, Sven, Montet, Benjamin T.
Formato: Preprint
Publicado: 2024
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author Banks, Kirsten A.
Martell, Sarah L.
Tinney, C. G.
Stello, Dennis
Hon, Marc
Reyes, Claudia
Priest, James
Buder, Sven
Montet, Benjamin T.
author_facet Banks, Kirsten A.
Martell, Sarah L.
Tinney, C. G.
Stello, Dennis
Hon, Marc
Reyes, Claudia
Priest, James
Buder, Sven
Montet, Benjamin T.
contents Although red clump stars function as reliable standard candles, their surface characteristics (i.e. $T_\text{eff}$, $\log g$, and [Fe/H]) overlap with those of red giant branch stars, which are not standard candles. Recent results have revealed that spectral features containing carbon (e.g. CN molecular bands) carry information correlating with the "gold-standard" asteroseismic classifiers that distinguish red clump from red giant branch stars. However, the underlying astrophysical processes driving the correlation between these spectroscopic and asteroseismic quantities in red giants remain inadequately explored. This study aims to enhance our understanding of this "spectro-seismic" effect, by refining the list of key spectral features predicting red giant evolutionary state. In addition, we conduct further investigation into those key spectral features to probe the astrophysical processes driving this connection. We employ the data-driven The Cannon algorithm to analyse high-resolution ($R\sim80,000$) Veloce Rosso spectra from the Anglo-Australian Telescope for 301 red giant stars (where asteroseismic classifications from the TESS mission are known for 123 of the stars). The results highlight molecular spectroscopic features, particularly those containing carbon (e.g. CN), as the primary indicators of the evolutionary states of red giant stars. Furthermore, by investigating CN isotopic pairs (that is, $^{12}$C$^{14}$N and $^{13}$C$^{14}$N) we find suggestions of statistically significant differences in the reduced equivalent widths of such lines, suggesting that physical processes that change the surface abundances and isotopic ratios in red giant stars, such as deep mixing, are the driving forces of the "spectro-seismic" connection of red giants.
format Preprint
id arxiv_https___arxiv_org_abs_2401_13235
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The role of carbon in red giant spectro-seismology
Banks, Kirsten A.
Martell, Sarah L.
Tinney, C. G.
Stello, Dennis
Hon, Marc
Reyes, Claudia
Priest, James
Buder, Sven
Montet, Benjamin T.
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Although red clump stars function as reliable standard candles, their surface characteristics (i.e. $T_\text{eff}$, $\log g$, and [Fe/H]) overlap with those of red giant branch stars, which are not standard candles. Recent results have revealed that spectral features containing carbon (e.g. CN molecular bands) carry information correlating with the "gold-standard" asteroseismic classifiers that distinguish red clump from red giant branch stars. However, the underlying astrophysical processes driving the correlation between these spectroscopic and asteroseismic quantities in red giants remain inadequately explored. This study aims to enhance our understanding of this "spectro-seismic" effect, by refining the list of key spectral features predicting red giant evolutionary state. In addition, we conduct further investigation into those key spectral features to probe the astrophysical processes driving this connection. We employ the data-driven The Cannon algorithm to analyse high-resolution ($R\sim80,000$) Veloce Rosso spectra from the Anglo-Australian Telescope for 301 red giant stars (where asteroseismic classifications from the TESS mission are known for 123 of the stars). The results highlight molecular spectroscopic features, particularly those containing carbon (e.g. CN), as the primary indicators of the evolutionary states of red giant stars. Furthermore, by investigating CN isotopic pairs (that is, $^{12}$C$^{14}$N and $^{13}$C$^{14}$N) we find suggestions of statistically significant differences in the reduced equivalent widths of such lines, suggesting that physical processes that change the surface abundances and isotopic ratios in red giant stars, such as deep mixing, are the driving forces of the "spectro-seismic" connection of red giants.
title The role of carbon in red giant spectro-seismology
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2401.13235