The Mass Dependence of Hα Emission and Stellar Spindown for Fully Convective M Dwarfs

Fuente: arXiv
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Autori principali: Pass, Emily K., Charbonneau, David, Latham, David W., Berlind, Perry, Calkins, Michael L., Esquerdo, Gilbert A., Mink, Jessica
Natura: Preprint
Pubblicazione: 2024
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author Pass, Emily K.
Charbonneau, David
Latham, David W.
Berlind, Perry
Calkins, Michael L.
Esquerdo, Gilbert A.
Mink, Jessica
author_facet Pass, Emily K.
Charbonneau, David
Latham, David W.
Berlind, Perry
Calkins, Michael L.
Esquerdo, Gilbert A.
Mink, Jessica
contents Fully convective M dwarfs typically remain rapidly rotating and magnetically active for billions of years, followed by an abrupt and mass-dependent transition to slow rotation and quiescence. A robust understanding of this process is complicated by difficulties in estimating M-dwarf ages and potential dependencies on other variables such as birth environment or metallicity. To isolate the effect of mass, we consider M dwarfs in wide binaries. We identify 67 widely separated, fully convective (0.08-0.35M$_\odot$) M-dwarf binary systems using Gaia and measure the H$α$ feature for each component. We classify the pairs into three categories: systems where both components are active, systems where both are inactive, and candidate transition systems, where one component is active and the other inactive. We gather higher-resolution spectra of the candidate transition systems to verify that their behavior does not result from an unresolved third component, yielding one new triple with surprising activity levels. Neglecting this triple, we find 22 active, 36 inactive, and 8 transition pairs. Our results are consistent with the epoch of spindown for these binaries being primarily determined by mass, with mild second-order effects; we place a 1$σ$ upper limit of 0.5Gyr or 25% on the dispersion in the mass-dependent spindown relation. Our findings suggest that the large dispersion in spindown epoch previously observed for field stars of a given mass may stem from differences in birth environment, in addition to modest intrinsic stochasticity. We also see evidence that the wide binary population is dispersed over time due to dynamical processing.
format Preprint
id arxiv_https___arxiv_org_abs_2401_10167
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Mass Dependence of Hα Emission and Stellar Spindown for Fully Convective M Dwarfs
Pass, Emily K.
Charbonneau, David
Latham, David W.
Berlind, Perry
Calkins, Michael L.
Esquerdo, Gilbert A.
Mink, Jessica
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Fully convective M dwarfs typically remain rapidly rotating and magnetically active for billions of years, followed by an abrupt and mass-dependent transition to slow rotation and quiescence. A robust understanding of this process is complicated by difficulties in estimating M-dwarf ages and potential dependencies on other variables such as birth environment or metallicity. To isolate the effect of mass, we consider M dwarfs in wide binaries. We identify 67 widely separated, fully convective (0.08-0.35M$_\odot$) M-dwarf binary systems using Gaia and measure the H$α$ feature for each component. We classify the pairs into three categories: systems where both components are active, systems where both are inactive, and candidate transition systems, where one component is active and the other inactive. We gather higher-resolution spectra of the candidate transition systems to verify that their behavior does not result from an unresolved third component, yielding one new triple with surprising activity levels. Neglecting this triple, we find 22 active, 36 inactive, and 8 transition pairs. Our results are consistent with the epoch of spindown for these binaries being primarily determined by mass, with mild second-order effects; we place a 1$σ$ upper limit of 0.5Gyr or 25% on the dispersion in the mass-dependent spindown relation. Our findings suggest that the large dispersion in spindown epoch previously observed for field stars of a given mass may stem from differences in birth environment, in addition to modest intrinsic stochasticity. We also see evidence that the wide binary population is dispersed over time due to dynamical processing.
title The Mass Dependence of Hα Emission and Stellar Spindown for Fully Convective M Dwarfs
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
url https://arxiv.org/abs/2401.10167