Isochrones of M67 with an Expanded Set of Parameters

Viani, Lucas S.; Basu, Sarbani

doi:10.1051/epjconf/201716005005

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…Michaud et al [192] argued that no CBM is required to reproduce the observed CMD of either M67 or NGC 188 if microscopic diffusion is included in the models. A similar conclusion for M67 was later found by Viani and Basu [193].…”

Section: Empirical Calibrations 41 Stellar Clusterssupporting

confidence: 89%

“…The sample in panel b was modeled using the Cesam2k code both with (open squares) and without (filled circles) microscopic diffusion, indicating that less CBM is needed to explain the observations if microscopic diffusion is taken into account [315]. This is in line with previous results from the open cluster M67 [192,193]. In comparison, the sample in panel c was modeled using the YREC code, using the concept of an effective overshoot parameter which accounts for the automatic adjustment of the size of the CBM region to avoid nonsensical core sizes [73].…”

Section: Extent Of the Cbm Region Across The Main-sequencesupporting

confidence: 86%

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Convective Boundary Mixing in Main-Sequence Stars: Theory and Empirical Constraints

Anders

Pedersen

2023

Galaxies

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The convective envelopes of solar-type stars and the convective cores of intermediate- and high-mass stars share boundaries with stable radiative zones. Through a host of processes we collectively refer to as “convective boundary mixing” (CBM), convection can drive efficient mixing in these nominally stable regions. In this review, we discuss the current state of CBM research in the context of main-sequence stars through three lenses. (1) We examine the most frequently implemented 1D prescriptions of CBM—exponential overshoot, step overshoot, and convective penetration—and we include a discussion of implementation degeneracies and how to convert between various prescriptions. (2) Next, we examine the literature of CBM from a fluid dynamical perspective, with a focus on three distinct processes: convective overshoot, entrainment, and convective penetration. (3) Finally, we discuss observational inferences regarding how much mixing should occur in the cores of intermediate- and high-mass stars as well as the implied constraints that these observations place on 1D CBM implementations. We conclude with a discussion of pathways forward for future studies to place better constraints on this difficult challenge in stellar evolution modeling.

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Section: Empirical Calibrations 41 Stellar Clusterssupporting

confidence: 89%

Section: Extent Of the Cbm Region Across The Main-sequencesupporting

confidence: 86%

Convective Boundary Mixing in Main-Sequence Stars: Theory and Empirical Constraints

Anders

Pedersen

2023

Galaxies

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“…Previous studies have estimated the age of M67 to be within the range of 3.5-5.5 Gyr ( [13], [14], [15], [16], [17], [18]), in which our obtained value of 4.26 Gyr lies. One study [19] suggested that the Sun might have formed within a cluster sharing many of its properties (such as metallicity) with M67.…”

Section: Estimation Of Age Metallicity and Extinctionsupporting

confidence: 56%

Membership and age determination of M67 open cluster using GAIA EDR3 data

Ghosh

Sulistiyowati²,

Tucio

et al. 2022

J. Phys.: Conf. Ser.

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We present our study on the membership and age determination of M67 (NGC 2682), one of the oldest open clusters known to date. Proper motions and parallax of stars collected in the Gaia Early Data Release 3 are used to derive the cluster members by employing the Hierarchical Density-Based Spatial Clustering of Applications with Noise algorithm, which is further improved upon using a Gaussian Mixture Model. We calculate the position of the cluster centre and the parallax to be α = 08h51m24s±1m33s, δ = 11°49’12"±0°22’48" and 1.1497±0.06 mas respectively. The proper motion of the cluster is obtained to be μa = −10.96 ± 0.20 mas/yr and μs = −2.90 ± 0.19 mas/yr. Subsequently, we perform an isochrone fitting to the Color-Magnitude Diagram (CMD) of M67 source members by using the Automated Stellar Cluster Analysis tool (ASteCA). Our findings estimate the log age, metallicity (z), reddening (EB–V ), and distance modulus (m – M)0 to be 9.630 ± 0.033 log-years, 0.01865 ± 0.001, 0.037 ± 0.008, and 9.409 ± 0.031 respectively.

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“…Since gravitational settling in higher-mass models leads to the unobserved consequence of zero-metallicity atmospheres unless it is resisted by mass loss or radiative levitation (e.g., Deal et al 2018), the computation of which is computationally expensive, we tapered off diffusion for evolutionary tracks with M > 1.25 M according to the equation given by Viani & Basu (2017). Despite the unphysical nature of this prescription, the star under investigation here is of a low enough mass that the diffusion-tapered models are irrelevant.…”

Section: Effect Of Input Physicsmentioning

confidence: 99%

Testing Stellar Evolution with Asteroseismic Inversions of a Main-sequence Star Harboring a Small Convective Core

Bellinger

Basu

Hekker

et al. 2019

ApJ

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The goal of stellar evolution theory is to predict the structure of stars throughout their lifetimes. Usually, these predictions can be assessed only indirectly, for example by comparing predicted and observed effective temperatures and luminosities. Thanks now to asteroseismology, which can reveal the internal structure of stars, it becomes possible to compare the predictions from stellar evolution theory to actual stellar structures. In this work, we present an inverse analysis of the oscillation data from the solar-type star KIC 6225718, which was observed by the Kepler space observatory during its nominal mission. As its mass is about 20% greater than solar, this star is predicted to transport energy by convection in its nuclear-burning core. We find significant differences between the predicted and actual structure of the star in the radiative interior near to the convective core. In particular, the predicted sound speed is higher than observed in the deep interior of the star, and too low at a fractional radius of 0.25 and beyond. The cause of these discrepancies is unknown, and is not remedied by known physics in the form of convective overshooting or elemental diffusion.

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Isochrones of M67 with an Expanded Set of Parameters

Cited by 7 publications

References 20 publications

Convective Boundary Mixing in Main-Sequence Stars: Theory and Empirical Constraints

Convective Boundary Mixing in Main-Sequence Stars: Theory and Empirical Constraints

Membership and age determination of M67 open cluster using GAIA EDR3 data

Testing Stellar Evolution with Asteroseismic Inversions of a Main-sequence Star Harboring a Small Convective Core

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