Exploring wind-driving dust species in cool luminous giants I. Basic criteria and dynamical models of M-type AGB stars

Abstract

This work is part of an ongoing effort aiming at identifying the actual wind-drivers among the dust species observed in circumstellar envelopes. In particular, we focus on the interplay between a strong stellar radiation field and the dust formation process. To identify critical properties of potential wind-driving dust species we use detailed radiation-hydrodynamical models which include a parameterized dust description, complemented by simple analytical estimates to help with the physical interpretation of the numerical results. The adopted dust description is constructed to mimic different chemical and optical dust properties in order to systematically study the effects of a realistic radiation field on the second stage of the mass loss mechanism. We see distinct trends in which combinations of optical and chemical dust properties are needed to trigger an outflow. Dust species with a low condensation temperature and a NIR absorption coefficient that decreases strongly with wavelength will not condense close enough to the stellar surface to be considered as potential wind-drivers. Our models confirm that metallic iron and Fe-bearing silicates are not viable as wind-drivers due to their near-infrared optical properties and resulting large condensation distances. TiO2 is also excluded as a wind-driver due to the low abundance of Ti. Other species, such a SiO2 and Al2O3, are less clear-cut cases due to uncertainties in the optical and chemical data and further work is needed. A strong candidate is Mg2SiO4 with grain sizes of 0.1-1 micron, where scattering contributes significantly to the radiative acceleration, as suggested by earlier theoretical work and supported by recent observations.

15 pages, 12 figures

References in corpus (3)

• Too little radiation pressure on dust in the winds of oxygen-rich AGB stars
• A close halo of large transparent grains around extreme red giant stars
• The Mira variable S Ori: Relationships between the photosphere, molecular layer, dust shell, and SiO maser shell at 4 epochs

Cited by in corpus (24)

• Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. II. Gas-to-Dust Ratio Variations across ISM Phases
• Luminosities and mass-loss rates of Local Group AGB stars and Red Supergiants
• Evolution of Thermally Pulsing Asymptotic Giant Branch Stars IV. Constraining Mass-Loss & Lifetimes of Low Mass, Low Metallicity AGB Stars
• The orbital evolution of asteroids, pebbles and planets from giant branch stellar radiation and winds
• Exploring wind-driving dust species in cool luminous giants III. Wind models for M-type AGB stars: dynamic and photometric properties
• Analytic, dust-independent mass-loss rates for red supergiant winds initiated by turbulent pressure
• An extensive grid of DARWIN models for M-type AGB stars I. Mass-loss rates and other properties of dust-driven winds
• The evolution of DARWIN: current status of wind models for AGB stars
• Exploring the origin of clumpy dust clouds around cool giants. A global 3D RHD model of a dust-forming M-type AGB star
• METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. II. Variations of interstellar depletions and dust-to-gas ratio within the LMC
• METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble program. I. Overview and Initial Results
• Carbon star wind models at solar and sub-solar metallicities: a comparative study. I. Mass loss and the properties of dust-driven winds
• ATOMIUM: ALMA tracing the origins of molecules in dust forming oxygen rich M-type stars: Motivation, sample, calibration, and initial results
• Search for aluminium monoxide in the winds of oxygen-rich AGB stars
• The wind of the M-type AGB star RT Virginis probed by VLTI/MIDI
• Abundance analysis for long-period variables II. RGB and AGB stars in the globular cluster 47\,Tuc
• Dust-depletion sequences in damped Ly-α absorbers II. The composition of cosmic dust, from low-metallicity systems to the Galaxy
• Micron-sized forsterite grains in the pre-planetary nebula of IRAS 17150-3224 - Searching for clues on the mysterious evolution of massive AGB stars
• Model of the vibrationally excited H${}_2$O maser at 658 GHz in circumstellar envelopes around asymptotic giant branch stars
• Circumstellar CO J = 3-2 detected around the evolving metal-poor ([Fe/H] ~ -1.15 dex) AGB star RU Vulpeculae
• The K-band highest-resolution images of the Mira star R Car with GRAVITY-VLTI
• LIN 358: A symbiotic binary accreting above the steady hydrogen fusion limit
• CO J = 2 - 1 Emission from Evolved Stars in the Galactic Bulge
• 3D models of the circumstellar environments of evolved stars: Formation of multiple spiral structures