A5060847019- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Sports Dynamics and Biomechanics
- Geophysics and Gravity Measurements
- Relativity and Gravitational Theory
- Galaxies: Formation, Evolution, Phenomena
- Experimental and Theoretical Physics Studies
- Atmospheric Ozone and Climate
- Black Holes and Theoretical Physics
- Aerodynamics and Fluid Dynamics Research
- Tropical and Extratropical Cyclones Research
- Aeolian processes and effects
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Calibration and Measurement Techniques
- Inorganic Fluorides and Related Compounds
Adolfo Ibáñez University
2021-2024
Nicolaus Copernicus Astronomical Center
2023-2024
Polish Academy of Sciences
2023-2024
Pontificia Universidad Católica de Chile
2022-2024
University of Valparaíso
2016-2022
Valparaiso University
2021
University of Concepción
2013-2014
Massive stars drive the ionization and mechanical feedback within young star-forming regions. The Large Magellanic Cloud (LMC) is an ideal galaxy for studying individual massive quantifying their contribution to environment. We analyze eight exemplary targets in LMC N11,B from Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) program using novel spectra UV, VLT ( optical. model early late O-type state-of-the-art PoWR atmosphere models. determine stellar wind parameters...
Massive stars are characterised by powerful stellar winds driven radiation; thus, the mass-loss rate is known to play a crucial role in their evolution. We study evolution of two massive (a classical star and very star) at solar metallicity (Z=0.014) detail. calculate final masses, radial expansion, chemical enrichment, H-core, He-core, C-core burning stages, prior collapse. ran evolutionary models for initial masses $60$ $200$ M_⊙ using MESA Geneva-evolution-code ( Genec ). For mass loss,...
Abstract In high-metallicity environments the mass that black holes (BHs) can reach just after core collapse widely depends on how much their progenitor stars lose via winds. On one hand, new theoretical and observational insights suggest early-stage winds should be weaker than what many canonical models prescribe. other proximity to Eddington limit affect formation of optically thick envelopes already during earliest stages with initial masses M ZAMS ≳ 100 ⊙ , hence resulting in higher...
Mass loss due to line-driven winds is central our understanding of the evolution massive stars. We extend models introduced in Paper I, where mass recipe based on simultaneous calculation wind hydrodynamics and line-acceleration, by incorporating effects stellar rotation. introduce a grid self-consistent line-force parameters for set standard evolutionary tracks. With that, we generate new tracks with rotation $M_\text{ZAMS}=25,40,70,$ $120\,M_\odot$, metallicities $Z=0.014$ $0.006$. The...
Context. [...] One of the most efficient methods is measurement equivalent width (EW) Calcium II Triplet (CaT), corrected for luminosity and temperature effects via magnitude differences from horizontal branch (HB). Methods. We use Ks difference between star reddest part HB (RHB) to generate reduced widths (rEW) datasets presented in Saviane et al. (2012) Rutledge (1997). Subsequently we calibrated these rEW against three different metellicity (met) scales: one Carretta (2009), met values...
Here we present evolutionary models for a set of massive stars, introducing new prescription the mass-loss rate obtained from hydrodynamical calculations in which wind velocity profile, $v(r)$, and line-acceleration, $g_\text{line}$, are self consistently way. Replacing rates at Main Sequence stage standard Vink's formula by our recipe, generate tracks $M_\text{ZAMS}=25,40,70$ $120\,M_\odot$ metallicities $Z=0.014$ (Galactic), $Z=0.006$ (LMC), $Z=0.002$ (SMC). Our derived predicts dependence...
Aims. We aim to measure the impact of our mass-loss recipe in evolution massive stars at metallicity Small Magellanic Cloud (SMC). Methods. used Geneva-evolution code (G ENEC ) run evolutionary tracks for stellar masses ranging from 20 85 M ⊙ SMC ( Z = 0.002). upgraded winds by replacing Vink’s formula with self-consistent m-CAK prescription, which reduces value rate, Ṁ , a factor between two and six depending on mass range. Results. The new [weaker] is wide, it can be divided direct...
Hot massive stars present strong stellar winds that are driven by absorption, scattering and re\-emission of photons the ions atmosphere (\textit{line-driven winds}). A better comprehension this phenomenon, a more accurate calculation hydrodynamics radiative acceleration is required to reduce number free parameters in spectral fitting, determine wind such as mass-loss rates velocity profiles. We use non-LTE model-atmosphere code CMFGEN numerically solve transfer equation calculate...
Fundamental parameters characterizing the end-state of intermediate-mass stars may be constrained by discovering planetary nebulae (PNe) in open clusters (OCs). Cluster membership exploited to establish distance, luminosity, age, and physical size for PNe, intrinsic luminosity mass its central star. Four potential PN-OC associations were investigated, assess cluster PNe. Radial velocities measured from intermediate-resolution optical spectra, complemented with previous estimates literature....
We perform spectral fitting for a set of O-type stars based on self-consistent wind solutions, which provide mass-loss rate and velocity profiles directly derived from the initial stellar parameters. The great advantage this is therefore reduction number free parameters to be tuned. Self-consistent values line-force (k,alpha,delta) subsequently terminal are provided by m-CAK prescription introduced in Paper I, updated work with improvements such as temperature structure wind,...
With the aim of understanding massive stars and their feedback in early epochs our Universe, ULLYSES XShootU collaborations collected biggest homogeneous dataset high-quality hot star spectra at low metallicity. Within rich ``zoo'' stellar types, B supergiants (BSGs) represent an important connection between main sequence more extreme evolutionary stages. Additionally, lying toward cool end regime, determining wind properties is crucial to gauging expectations on evolution as, for instance,...
We use Geneva-evolution-code to run evolutionary tracks for stellar masses ranging from $20$ $85$ $M_\odot$ at SMC metallicity ($Z=0.002$). upgrade the recipe winds by adopting our self-consistent m-CAK prescription, which reduces value of mass-loss rate a factor between 2 and 6 depending on mass range. The impact new is wide, it can be divided direct indirect impact. For most massive models ($60$ $M_\odot$) with $\dot M\gtrsim2\times10^{-7}$ yr$^{-1}$, because lower loss make stars remove...
CONTEXT: The spectral analysis of hot, massive stars is a fundamental astrophysical method to obtain their intrinsic properties and feedback. Quantitative spectroscopy for requires detailed numerical modeling the atmosphere an iterative treatment best solution within given framework. AIMS: We present overview different techniques quantitative hot employed X-Shooting ULLYSES collaboration, from grid-based approaches tailored fits. By performing blind test, we gain about similarities...
Context. The spectral analysis of hot, massive stars is a fundamental astrophysical method determining their intrinsic properties and feedback. With inherent, radiation-driven winds, the quantitative spectroscopy for requires detailed numerical modeling atmosphere an iterative treatment in order to obtain best solution within given framework. Aims. We present overview different techniques hot employed X-Shooting ULLYSES collaboration, ranging from grid-based approaches tailored fits. By...
We study in detail the evolution of two massive stars at solar metallicity (Z=0.014) taken from Romagnolo et al. (2024, Paper I); by running models for initial masses 60 and 200 Msun, using MESA GENEC. For mass loss, we adopt self-consistent m-CAK prescription optically thin winds OB-stars, a semi-empirical formula H-rich thick wind WNh stars, hydrodynamically consistent H-poor classical Wolf-Rayet stars. set rotation as 40% critical angular velocity, overshooting =0.5, Tayler-Spruit...
Massive stars lead the ionization and mechanical feedback within young star-forming regions. The Large Magellanic Cloud (LMC) is an ideal galaxy for studying individual massive quantifying their contribution to environment. We analyze eight exemplary targets in LMC N11 B from Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) program, using novel spectra HST (COS STIS) UV, VLT (X-shooter) optical. model early late O-type by state-of-the-art PoWR atmosphere models....
Context. B supergiants (BSGs) represent an important connection between the main sequence and more extreme evolutionary stages of massive stars. Additionally, lying toward cool end hot star regime, determining their wind properties is crucial to constrain evolution feedback stars as, for instance, they might manifest bi-stability jump phenomenon. Aims. We undertake a detailed analysis representative sample 18 Small Magellanic Cloud (SMC) BSGs within ULLYSES XShootU datasets. Our UV optical...
Abstract Massive stars present strong stellar winds that are described by the radiation driven wind theory. Accurate mass-loss rates necessary to properly describe evolution across Hertzsprung–Russel Diagram. We a self-consistent procedure coupled hydrodynamics with calculations of line-force, giving as results line-force parameters, velocity field, and rate. Our contemplate contribution multiplier from more than ∼900,000 atomic transitions, an NLTE flux photosphere quasi-LTE approximation...
ABSTRACT The theory of line-driven winds can explain many observed spectral features in early-type stars, though our understanding the B supergiants remains incomplete. hydrodynamic equations for slowly rotating stellar predict two regimes based on line-force parameter δ: fast and δ-slow solution. In this paper, we aim to explore capability latter properties supergiant winds. We calculate Hα line profiles, most sensitive wind diagnostics optical, both models. fit them data from a...
Accurate mass-loss rates and terminal velocities from massive stars winds are essential to obtain synthetic spectra radiative transfer calculations determine the evolutionary path of stars. From a theoretical point view, analytical expressions for wind parameters velocity profile would have many advantages over numerical that solve complex non-linear set hydrodynamic equations. In previous work, we obtained an description fast regime. Now, propose approximate expression line-force in terms...
An abstract is not available for this content so a preview has been provided. As you have access to content, full PDF via the ‘Save PDF’ action button.
Abstract We present the first results of our analysis famous variable star, WR6 (HD50896). Using IUE ultraviolet data and an ESPaDOnS spectropolarimetric survey this we plan to determine possible variation stellar wind parameters during different phases using radiative transfer code CMFGEN. After detection parameter's modifications as a function phase, will analyse deeper origin these variability (for example, CIRs?). In poster show step parameter determination average spectrum star.
Abstract In the frame of radiation driven wind theory (Castor et al. 1975), we present self-consistent hydrodynamical solutions to line-force parameters ( k , α, δ) under LTE conditions. Hydrodynamic models are provided by HydWind (Curé 2004). We evaluate these results with those ones previously found in literature, focusing different regions optical depth be used perform calculations. The values for mass-loss rate and terminal velocity obtained from our calculations also presented. examine...