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Main Authors: Taylor, Anna, Dunn, Audrey, Peacock, Sarah, Youngblood, Allison, Redfield, Seth
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2402.00934
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author Taylor, Anna
Dunn, Audrey
Peacock, Sarah
Youngblood, Allison
Redfield, Seth
author_facet Taylor, Anna
Dunn, Audrey
Peacock, Sarah
Youngblood, Allison
Redfield, Seth
contents The Mg II h&k emission lines (2803, 2796 A) are a useful tool for understanding stellar chromospheres and transition regions due to their intrinsic brightness, relatively low interstellar medium (ISM) absorption interference, and abundance of archival spectra available. Similar to other optically thick chromospheric emission lines such as H I Lya, Mg II emissions commonly present with a self-reversed line core, the depth and shape of which vary from star to star. We explore the relationship between self-reversal and the stellar atmosphere by investigating the extent that fundamental stellar parameters affect self-reversal. We present a search for correlations between photospheric parameters such as effective temperature, surface gravity, and metallicity with the Mg II k self-reversal depth for a group of 135 FGKM main sequence stars with high-resolution near-ultraviolet spectra from the Hubble Space Telescope. We modeled the observed MgII k line profiles to correct for ISM attenuation and recover the depth of emission line's self-reversal in relation to the intensity of the line. We used the PHOENIX atmosphere code to homogeneously determine the stellar parameters by computing a suite of stellar atmosphere models that include a chromosphere and transition region, and using archival photometry to guide the models of each star. We quantify the sensitivity of the visible and near-infrared photometry to chromospheric and photospheric parameters. We find weak trends between Mg II k self-reversal depth and age, rotation period, Mg II luminosity, temperature, and mass. All stars in our sample older than ~2 Gyr or rotating slower than ~10 days exhibit self-reversal.
format Preprint
id arxiv_https___arxiv_org_abs_2402_00934
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Correlating Intrinsic Stellar Parameters with Mg II Self-Reversal Depths
Taylor, Anna
Dunn, Audrey
Peacock, Sarah
Youngblood, Allison
Redfield, Seth
Solar and Stellar Astrophysics
The Mg II h&k emission lines (2803, 2796 A) are a useful tool for understanding stellar chromospheres and transition regions due to their intrinsic brightness, relatively low interstellar medium (ISM) absorption interference, and abundance of archival spectra available. Similar to other optically thick chromospheric emission lines such as H I Lya, Mg II emissions commonly present with a self-reversed line core, the depth and shape of which vary from star to star. We explore the relationship between self-reversal and the stellar atmosphere by investigating the extent that fundamental stellar parameters affect self-reversal. We present a search for correlations between photospheric parameters such as effective temperature, surface gravity, and metallicity with the Mg II k self-reversal depth for a group of 135 FGKM main sequence stars with high-resolution near-ultraviolet spectra from the Hubble Space Telescope. We modeled the observed MgII k line profiles to correct for ISM attenuation and recover the depth of emission line's self-reversal in relation to the intensity of the line. We used the PHOENIX atmosphere code to homogeneously determine the stellar parameters by computing a suite of stellar atmosphere models that include a chromosphere and transition region, and using archival photometry to guide the models of each star. We quantify the sensitivity of the visible and near-infrared photometry to chromospheric and photospheric parameters. We find weak trends between Mg II k self-reversal depth and age, rotation period, Mg II luminosity, temperature, and mass. All stars in our sample older than ~2 Gyr or rotating slower than ~10 days exhibit self-reversal.
title Correlating Intrinsic Stellar Parameters with Mg II Self-Reversal Depths
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2402.00934