相关论文: Dust formation in the oxygen-rich AGB star IK Tau
Low- and intermediate-mass stars at the asymptotic giant branch (AGB) are known to be prevalent dust providers to galaxies. However, the mechanisms responsible for the formation and acceleration of dust in the cool extended atmospheres of…
Context. AGB stars go through a process of strong mass-loss that involves pulsations of the atmosphere, which extends to a region where the conditions are adequate for dust grains to form. Radiation pressure acts on these grains which,…
Dust grains forming in the extended atmospheres of AGB stars are critical for the heavy mass loss of these cool luminous giants, as they provide radiative acceleration for the stellar winds. Characteristic mid-IR spectral features indicate…
We present new models for the evolution of stars with mass in the range 1Msun < M < 7.5Msun, followed from the pre-main-sequence through the asymptotic giant branch phase. The metallicity adopted is $Z=3*10^{-4} (which, with an…
Aims. We model the chemistry of the inner wind of the carbon star IRC+10216 and consider the effect of periodic shocks induced by the stellar pulsation on the gas to follow the non-equilibrium chemistry in the shocked gas layers. We…
Aims: Little information exists on the circumstellar molecular abundance stratifications of many molecules. The aim is to study the circumstellar chemical abundance pattern of 11 molecules and isotopologs ($^{12}$CO, $^{13}$CO, SiS,…
We compute the mass and composition of dust produced by stars with masses in the range 1Msun<M<8 Msun and with a metallicity of Z=0.001 during their AGB and Super AGB phases. Stellar evolution is followed from the pre-main sequence phase…
The formation of silicate dust in oxygen-rich envelopes of evolved stars is thought to be initiated by formation of seed particles that can withstand the high temperatures close to the stellar photosphere and act as condensation cores…
We investigate the composition of the solid-state materials in the winds around S-type AGB stars. The S stars produce dust in their wind that bears a resemblance to the dust produced in some O-rich AGB stars. However, the reported…
The gas-phase non-equilibrium chemistry of the inner wind of the oxygen-rich Mira variable IK Tau (NML Tau) is investigated using a physio-chemical model describing the periodically shocked gas close to the stellar photosphere. We predict…
(abbreviated) We aim to constrain the dust formation histories in the winds of oxygen-rich AGB stars. We have obtained ALMA observations with a spatial resolution of 120x150 mas tracing the dust formation region of a low mass-loss rate and…
The aim of this paper is to study the molecular composition in the circumstellar envelope around the oxygen-rich star IK Tau. We observed IK Tau in several (sub)millimeter bands using the APEX telescope during three observing periods. To…
We aim to constrain the dust mass and grain sizes in the interaction regions between the stellar winds and the ISM around asymptotic giant branch stars. By describing the dust in these regions, we aim to shed light on the role of low mass…
Outflows of pre-main-sequence stars drive shocks into molecular material within 0.01 - 1 pc of the young stars. The shock-heated gas emits infrared, millimeter and submillimeter lines of many species including. Dust grains are important…
Context: Stars evolving through the asymptotic giant branch (AGB) phase provide significant feedback to their host system, in form of both gas enriched in nuclear-burning products and dust formed in their winds, which they eject into the…
The abundance evolution of interstellar dust species originating from stellar sources and from condensation in molecular clouds in the local interstellar medium of the Milky Way is studied and the input of dust material to the Solar System…
High spatial resolution techniques have given valuable insights into the mass loss mechanism of AGB stars, which presumably involves a combination of atmospheric levitation by pulsation-induced shock waves and radiation pressure on dust.…
Interstellar dust forms during stellar mass-loss events, occurring either during a star's giant phase or during supernova explosions. This PhD thesis provides an in-depth investigation into the theory of dust condensation and growth,…
The dust formation process in the winds of Asymptotic Giant Branch stars is discussed, based on full evolutionary models of stars with mass in the range $1$M$_{\odot} \leq$M$\leq 8$M$_{\odot}$, and metallicities $0.001 < Z <0.008$. Dust…
The formation of silicates in circumstellar envelopes of stars evolving through the AGB is still debated given the uncertainties affecting stellar evolution modelling, the description of the dust formation process, and the capability of…