Helium enrichment and Carbon-star Production in Metal-rich Populations

Abstract

We present new theoretical stellar evolutionary models of metal-rich asymptotic giant branch (AGB) stars. Stellar models are evolved with initial masses between 1Msun and 7Msun at Z=0.007, and 1Msun and 8Msun at Z=0.014 (solar) and at Z=0.03. We evolve models with a canonical helium abundance and with helium enriched compositions (Y=0.30, 0.35, 0.40) at Z=0.014 and Z=0.03. The efficiency of third dredge-up and the mass range of carbon stars decreases with an increase in metallicity. We predict carbon stars form from initial masses between 1.75-7Msun at Z=0.007 and between 2-4.5Msun at solar metallicity. At Z=0.03 the mass range for C-star production is narrowed to 3.25-4Msun. The third dredge-up is reduced when the helium content of the model increases owing to the reduced number of thermal pulses on the AGB. A small increase of Delta Y = 0.05 is enough to prevent the formation of C stars at Z=0.03, depending on the mass-loss rate, whereas at Z=0.014, an increase of Delta Y = 0.1 is required to prevent the formation of C stars. We speculate that the probability of finding C stars in a stellar population depends as much on the helium abundance as on the metallicity. To explain the paucity of C stars in the inner region of M31 we conclude that the observed stars have Y > 0.35 or that the stellar metallicity is higher than [Fe/H] ~ 0.1.

14 pages, accepted for publication in MNRAS

References in corpus (16)

• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Thermohaline mixing: A physical mechanism governing the photospheric composition of low-mass giants
• The Initial-Final Mass Relation: Direct Constraints at the Low Mass End
• The Gaia-ESO Survey: the Galactic Thick to Thin Disc transition
• The primordial abundance of 4He: a self-consistent empirical analysis of systematic effects in a large sample of low-metallicity HII regions
• Rotational mixing in low-mass stars II. Self-consistent models of Pop II RGB stars
• Near-Infrared Photometry of Carbon Stars
• The Helium abundance and Delta Y / Delta Z in Lower Main Sequence stars
• Magnetic Mixing in Red Giant and Asymptotic Giant Branch Stars
• The Chemical Evolution of Helium
• The Chemical Evolution of Helium in Globular Clusters: Implications for the Self-Pollution Scenario
• MHD and deep mixing in evolved stars. 1. 2D and 3D analytical models for the AGB
• Mass loss and yield uncertainty in low-mass asymptotic giant branch stars
• Technetium and the third dredge up in AGB stars II. Bulge stars
• Chemical abundances in Galactic planetary nebulae with Spitzer spectra
• Zinc abundances of planetary nebulae

Cited by in corpus (47)

• (Sub)stellar companions shape the winds of evolved stars
• Planetary Nebulae: Sources of Enlightenment
• 3D non-LTE line formation of neutral carbon in the Sun
• Multiple stellar populations and their evolution in globular clusters: A nucleosynthesis perspective
• Reconnaissance with JWST of the J-region Asymptotic Giant Branch in Distance Ladder Galaxies: From Irregular Luminosity Functions to Approximation of the Hubble Constant
• Reduction of the maximum mass-loss rate of OH/IR stars due to unnoticed binary interaction
• RR Lyrae From Binary Evolution: Abundant, Young and Metal-Rich
• On the Production of He, C and N by Low and Intermediate Mass Stars: A Comparison of Observed and Model-Predicted Planetary Nebula Abundances
• Astrophysical Distance Scale II. Application of the JAGB Method: A Nearby Galaxy Sample
• Origin of large meteoritic SiC stardust grains in metal-rich AGB stars
• C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines
• Understanding the evolution and dust formation of carbon stars in the LMC with a look at the JWST
• A Dramatic Decrease in Carbon Star Formation in M31
• A Fresh Look at AGB stars in Galactic Open Clusters with Gaia: Impact on Stellar Models and the Initial-Final Mass Relation
• Intermediate-mass asymptotic giant branch stars and sources of ${}^{26}$Al, ${}^{60}$Fe, ${}^{107}$Pd, and ${}^{182}$Hf in the solar system
• A bound on the 12C/13C ratio in near-pristine gas with ESPRESSO
• Multiwavelength Period-Luminosity and Period-Luminosity-Color relations at maximum-light for Mira variables in the Magellanic Clouds
• Hunting for C-rich long-period variable stars in the Milky Way's bar-bulge using unsupervised classification of Gaia BP/RP spectra
• The stellar beta-decay rate of 134Cs and its impact on the Barium nucleosynthesis in the s process
• Interplay between pulsation, mass loss, and third dredge-up: More about Miras with and without technetium
• High-temperature ${}^{205}$Tl decay clarifies ${}^{205}$Pb dating in early Solar System
• New Multielement Isotopic Compositions of Presolar SiC Grains: Implications for Their Stellar Origins
• The most metal-rich stars in the universe: chemical contributions of low and intermediate mass asymptotic giant branch stars with metallicities between $0.04\le Z\le \mathrm{0.10.}$
• Rubidium and zirconium abundances in massive Galactic asymptotic giant branch stars revisited
• Impact of Convective Boundary Mixing on the TP-AGB
• Witnessing the Emergence of a Carbon Star
• The Isaac Newton Telescope monitoring survey of Local Group dwarf galaxies -- IV. The star formation history of Andromeda VII derived from long period variable stars
• The most metal-rich asymptotic giant branch stars
• Bridging the Gap between Intermediate and Massive Stars I: Validation of MESA against the State-of-the-Art Monash Stellar Evolution Program for a 2$M_{\odot }$ AGB Star
• Carbon Stars in the Satellites and Halo of M31
• Study of extremely reddened AGB stars in the Galactic bulge
• A Census of Thermally-Pulsing AGB stars in the Andromeda Galaxy and a First Estimate of their Contribution to the Global Dust Budget
• Hubble Space Telescope Spectroscopy of a Planetary Nebula in an M31 Open Cluster: Hot-Bottom Burning at $3.4M_{\odot }$
• The Impact of the Third Dredge-up and Mass Loss in Shaping the Initial-Final Mass Relation of White Dwarfs
• Isotopic enrichment of planetary systems from Asymptotic Giant Branch stars
• CO line observations of OH/IR stars in the inner Galactic Bulge: Characteristics of stars at the tip of the AGB
• Physical and chemical properties of Wolf-Rayet planetary nebulae
• New Constraints on Sodium Production in Globular Clusters From the ${}^{23}$Na${(}^3$He$,\text{d}{)}^{24}$Mg Reaction
• First models of s process in AGB stars of solar metallicity for the stellar evolutionary code ATON with a novel stable explicit numerical solver
• s-process Enriched Post-AGB Star J003643.94-723722.1 in the SMC with an Extreme C/O Ratio and the First Precise Detection of Lead
• Evidence for the Keplerian orbit of a close companion around a giant star
• Emission-line stars in M31 from the SPLASH and PHAT surveys
• Aluminium-26 production in low- and intermediate-mass binary systems
• Impact of $\text{T}$- and $\rho$-dependent decay rates and new (n,$\gamma$) cross sections on the $\text{s}$ process in low-mass AGB stars
• The Predicted Properties of Helium-Enriched Globular Cluster Progenitors at High Redshift
• Detached Shell Carbon Stars: Tracing Thermal Pulses on the Asymptotic Giant Branch
• Gas and dust from extremely metal-poor AGB stars