The ancient main-sequence solar proxy HIP 102152 unveils the activity and rotational fate of our Sun

Meléndez, Jorge; Ponte, Geisa; Galarza, Jhon Yana

doi:10.1093/mnrasl/slaa057

Cited by 16 publications

(8 citation statements)

References 43 publications

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“…Many observations exist of the rotation rates of solar-type stars of different ages (e.g., Stauffer & Hartmann 1986;McQuillan et al 2014;García et al 2014;Gallet & Bouvier 2015;dos Santos et al 2016;Lorenzo-Oliveira et al 2020). They clearly establish that the surface rotation of these stars evolves with time under the effect of multiple processes.…”

Section: Surface Rotationmentioning

confidence: 99%

Lithium depletion and angular momentum transport in solar-type stars

Dumont

Palacios

Charbonnel

et al. 2021

A&A

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Context. Transport processes occurring in the radiative interior of solar-type stars are evidenced by the surface variation of light elements, in particular 7Li, and the evolution of their rotation rates. For the Sun, inversions of helioseismic data indicate that the radial profile of angular velocity in its radiative zone is nearly uniform, which implies the existence of angular momentum transport mechanisms that are efficient over evolutionary timescales. While there are many independent transport models for angular momentum and chemical species, there is a lack of self-consistent theories that permit stellar evolution models to simultaneously match the present-day observations of solar lithium abundances and radial rotation profiles. Aims. We explore how additional transport processes can improve the agreement between evolutionary models of rotating stars and observations for 7Li depletion, the rotation evolution of solar-type stars, and the solar rotation profile. Methods. Models of solar-type stars are computed including atomic diffusion and rotation-induced mixing with the code STAREVOL. We explore different additional transport processes for chemicals and for angular momentum such as penetrative convection, tachocline mixing, and additional turbulence. We constrain the resulting models by simultaneously using the evolution of the surface rotation rate and 7Li abundance in the solar-type stars of open clusters with different ages, and the solar surface and internal rotation profile as inverted from helioseismology when our models reach the age of the Sun. Results. We show the relevance of penetrative convection for the depletion of 7Li in pre-main sequence and early main sequence stars. The rotational dependence of the depth of penetrative convection yields an anti-correlation between the initial rotation rate and 7Li depletion in our models of solar-type stars that is in agreement with the observed trend. Simultaneously, the addition of an ad hoc vertical viscosity νadd leads to efficient transport of angular momentum between the core and the envelope during the main sequence evolution and to solar-type models that match the observed profile of the Sun. We also self-consistently compute for the first time the thickness of the tachocline and find that it is compatible with helioseismic estimations at the age of the Sun, but we highlight that the associated turbulence does not allow the observed 7Li depletion to be reproduced. The main sequence depletion of 7Li in solar-type stars is only reproduced when adding a parametric turbulent mixing below the convective envelope. Conclusions. The need for additional transport processes in stellar evolution models for both chemicals and angular momentum in addition to atomic diffusion, meridional circulation, and turbulent shear is confirmed. We identify the rotational dependence of the penetrative convection as a key process. Two additional and distinct parametric turbulent mixing processes (one for angular momentum and one for chemicals) are required to simultaneously explain the observed surface 7Li depletion and the solar internal rotation profile. We highlight the need of additional constraints for the internal rotation of young solar-type stars and also for the beryllium abundances of open clusters in order to test our predictions.

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Section: Surface Rotationmentioning

confidence: 99%

Lithium depletion and angular momentum transport in solar-type stars

Dumont

Palacios

Charbonnel

et al. 2021

A&A

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“…Once they evolved off the main sequence and their radii increase, conservation of angular momentum implies that (single) stars will spin-down. Given that rotation and activity are related (Skumanich 1972;Pizzolato et al 2003;Vidotto et al 2014b;Lorenzo-Oliveira et al 2020), it is expected that these stars will become less active with age. Although the rotation of λ And is indeed slower than that of the Sun, its chromospheric Ca II H&K activity is stronger (Morris et al 2019).…”

mentioning

confidence: 99%

λ And: a post-main-sequence wind from a solar-mass star

Fionnagáin

Vidotto

Petit

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We investigate the wind of λ And, a solar-mass star that has evolved off the main sequence becoming a sub-giant. We present spectropolarimetric observations and use them to reconstruct the surface magnetic field of λ And. Although much older than our Sun, this star exhibits a stronger (reaching up to 83 G) large-scale magnetic field, which is dominated by the poloidal component. To investigate the wind of λ And, we use the derived magnetic map to simulate two stellar wind scenarios, namely a “polytropic wind” (thermally-driven) and an “Alfven-wave driven wind” with turbulent dissipation. From our 3D magnetohydrodynamics simulations, we calculate the wind thermal emission and compare it to previously published radio observations and more recent VLA observations, which we present here. These observations show a basal sub-mJy quiescent flux level at ∼5 GHz and, at epochs, a much larger flux density (>37 mJy), likely due to radio flares. By comparing our model results with the radio observations of λ And, we can constrain its mass-loss rate $\dot{M}$. There are two possible conclusions. 1) Assuming the quiescent radio emission originates from the stellar wind, we conclude that λ And has $\dot{M} \simeq 3 \times 10^{-9}$ M⊙ yr −1, which agrees with the evolving mass-loss rate trend for evolved solar-mass stars. 2) Alternatively, if the quiescent emission does not originate from the wind, our models can only place an upper limit on mass-loss rates, indicating that $\dot{M} \lesssim 3 \times 10^{-9}$ M⊙ yr −1.

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“…A case study of an ∼8 Gyr solar twin further reinforced these conclusions(Lorenzo-Oliveira et al 2020). …”

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confidence: 75%

Further Evidence of Modified Spin-down in Sun-like Stars: Pileups in the Temperature-Period Distribution

David,

Angus,

Curtis

et al. 2022

Preprint

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We combine stellar surface rotation periods determined from NASA's Kepler mission with spectroscopic temperatures to demonstrate the existence of pile-ups at the long-period and short-period edges of the temperature-period distribution for main-sequence stars with temperatures exceeding ∼5500 K. The long-period pile-up is well-described by a curve of constant Rossby number, with a critical value of Ro crit 2. The long-period pile-up was predicted by van Saders et al. ( 2019) as a consequence of weakened magnetic braking, in which wind-driven angular momentum losses cease once stars reach a critical Rossby number. Stars in the long-period pile-up are found to have a wide range of ages (∼2-6 Gyr), meaning that, along the pile-up, rotation period is strongly predictive of a star's surface temperature but weakly predictive of its age. The short-period pile-up, which is also well-described by a curve of constant Rossby number, is not a prediction of the weakened magnetic braking hypothesis but may instead be related to a phase of slowed surface spin-down due to core-envelope coupling. The same mechanism was proposed by Curtis et al. (2020) to explain the overlapping rotation sequences of low-mass members of differently aged open clusters. The relative dearth of stars with intermediate rotation periods between the short-and long-period pile-ups is also well-described by a curve of constant Rossby number, which aligns with the period gap initially discovered by McQuillan et al. (2013a) in M-type stars. These observations provide further support for the hypothesis that the period gap is due to stellar astrophysics, rather than a non-uniform star-formation history in the Kepler field.

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The ancient main-sequence solar proxy HIP 102152 unveils the activity and rotational fate of our Sun

Cited by 16 publications

References 43 publications

Lithium depletion and angular momentum transport in solar-type stars

Lithium depletion and angular momentum transport in solar-type stars

λ And: a post-main-sequence wind from a solar-mass star

Further Evidence of Modified Spin-down in Sun-like Stars: Pileups in the Temperature-Period Distribution

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