Asteroseismology of 36 Kepler subgiants -- II: Determining ages from detailed modelling

Abstract

Detailed modelling of stellar oscillations is able to give precise estimates for stellar ages, but the inferred results typically depend on the adopted model parameters used for the age inference. High-quality asteroseismic data with precise measurements of mixed modes are available for 36 Kepler subgiants. To obtain a handle on the robustness of the ages for these stars, we first study the dependencies of seismic ages on three model input parameters. We find that inferred ages do not change systematically with the helium fraction (Y) or the mixing-length parameter but depend strongly on the metallicity ([M/H]) of the model. The results indicate that age estimates of subgiants have less model dependence and hence are more reliable than those of main-sequence stars or red giants. We then model individual oscillation frequencies of the same 36 Kepler subgiants, using observed metallicities, and obtain their ages with an average precision of ~15%. The comparison with previous age estimates with different stellar codes or input physics shows good agreement (mostly within 2#). We hence suggest that seismology-determined ages of subgiants are not greatly model-dependent.

MNRAS Accepted

References in corpus (11)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Standing on the shoulders of Dwarfs: the Kepler asteroseismic LEGACY sample II - radii, masses, and ages
• A new correction of stellar oscillation frequencies for near-surface effects
• Mixed modes in red giants: a window on stellar evolution
• Improvements to stellar structure models, based on a grid of 3D convection simulations. II. Calibrating the mixing-length formulation
• A precise asteroseismic age and radius for the evolved Sun-like star KIC 11026764
• The Stagger-grid: A grid of 3D stellar atmosphere models - III. The relation to mixing-length convection theory
• Asteroseismic estimate of helium abundance of a solar analog binary system
• Modelling Kepler Red Giants in Eclipsing Binaries:Calibrating the Mixing Length Parameter with Asteroseismology
• Seismic measurement of the locations of the base of convection zone and helium ionization zone for stars in the {\it Kepler} seismic LEGACY sample
• Asteroseismic analysis of two alpha-enhanced stars KIC 7976303 and KIC 8694723

Cited by in corpus (24)

• Seismic evidence for near solid-body rotation in two Kepler subgiants and implications for angular momentum transport
• Discovery of post-mass-transfer helium-burning red giants using asteroseismology
• PBjam: A Python package for automating asteroseismology of solar-like oscillators
• Asteroseismology of 3,642 Kepler Red Giants: Correcting the Scaling Relations based on Detailed Modeling
• gyre_tides: Modeling binary tides within the gyre stellar oscillation code
• A prescription for the asteroseismic surface correction
• Improved Constraints on the Initial-to-Final Mass Relation of White Dwarfs using Wide Binaries
• Asteroseismic Inference of Subgiant Evolutionary Parameters with Deep Learning
• Testing the Limits of Precise Subgiant Characterization with APOGEE and Gaia: Opening a Window to Unprecedented Astrophysical Studies
• Testing abundance-age relations beyond solar analogues with Kepler LEGACY stars
• Precise Masses, Ages of ~1.0 million RGB and RC stars observed by the LAMOST
• Mixed Modes and Asteroseismic Surface Effects: II. Subgiant Systematics
• Multi-campaign Asteroseismic Analysis of eight Solar-like pulsating stars observed by the K2 mission
• Asteroseismic Study of Subgiants and Giants of the Open Cluster M67 using Kepler/K2: Expanded Sample and Precise Masses
• Revisiting the Red-giant Branch Hosts KOI-3886 and $\iota$ Draconis. Detailed Asteroseismic Modeling and Consolidated Stellar Parameters
• A binary with a $\delta$~Scuti star and an oscillating red giant: orbit and asteroseismology of KIC9773821
• A Homogeneous Catalog of Oscillating Solar-Type Stars Observed by the Kepler Mission and a New Amplitude Scaling Relation Including Chromospheric Activity
• Asteroseismic analysis of 15 solar-like oscillating evolved stars
• Uncovering the ultimate planet impostor. An eclipsing brown dwarf in a hierarchical triple with two evolved stars
• Asteroseismology with PBjam 2.0: measuring dipole mode frequencies in coupling regimes from main sequence to low-luminosity red giant stars
• Systematics in Asteroseismic Modelling: Application of a Correlated Noise Model for Oscillation Frequencies
• Is there a unique asteroseismic interior model for the solar-like oscillating KIC 7747078?
• Asteroseismology of iota Draconis and Discovery of an Additional Long-Period Companion
• New scaling relations from MESA models for mass and radius of subgiant stars: application to Kepler targets