Polarization of light from fast-rotating Wolf-Rayet stars: Monte Carlo simulations compared to the analytical formula

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00637346" target="_blank" >RIV/67985815:_____/25:00637346 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/25:00141857

Výsledek na webu

<a href="https://hdl.handle.net/11104/0368253" target="_blank" >https://hdl.handle.net/11104/0368253</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202553921" target="_blank" >10.1051/0004-6361/202553921</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Polarization of light from fast-rotating Wolf-Rayet stars: Monte Carlo simulations compared to the analytical formula

Popis výsledku v původním jazyce

Context. Fast-rotating Wolf-Rayet (WR) stars are potential progenitors of long gamma-ray bursts, but observational verification is challenging. Spectral lines from their expanding stellar wind obscure accurate rotational velocity measurements. Intrinsic polarization from wind rotation may help to determine rotational speeds. However, this procedure requires precise wind models. Aims. Our study aims to investigate the intrinsic polarization due to the rotational distortion of WR winds considering multiplescattering of photons and compare it to a single-scattering model, in which we use an analytical expression of the polarization. Methods. We studied the polarization signatures resulting from the prolate structure of rotating winds of two WR stars using a 3D Monte Carlo radiative transfer code Hyperion. We estimated the intrinsic polarization resulting from multiple-scattering in WR winds for different rotational velocities, inclination angles, and mass-loss rates. Results. Our results indicate that at a rotation rate of less than 50% of the critical rate, the intrinsic polarization from multiplescattering is close to that of a single-scattering model. However, at higher rotation velocities, the polarization from multiple-scattering increases with inclination up to 40 degrees, while it decreases for inclinations higher than about 60 degrees. This dependence is inconsistent with the single-scattering model. We also discuss the effect of the mass-loss rate on the polarization and find that the polarization changes linearly with the mass-loss rate. However, it is important to note that the relationship between polarization and mass-loss rate may vary for different types of stars. Conclusions. The results have implications for future studies of stellar winds and mass loss and may help to improve our understanding of the complex environments of massive stars. Our research offers valuable information on the complex polarization patterns observed in stellar winds, emphasizing the significance of accounting for the influence of multiple-scattering when interpreting observations.

Název v anglickém jazyce

Polarization of light from fast-rotating Wolf-Rayet stars: Monte Carlo simulations compared to the analytical formula

Popis výsledku anglicky

Context. Fast-rotating Wolf-Rayet (WR) stars are potential progenitors of long gamma-ray bursts, but observational verification is challenging. Spectral lines from their expanding stellar wind obscure accurate rotational velocity measurements. Intrinsic polarization from wind rotation may help to determine rotational speeds. However, this procedure requires precise wind models. Aims. Our study aims to investigate the intrinsic polarization due to the rotational distortion of WR winds considering multiplescattering of photons and compare it to a single-scattering model, in which we use an analytical expression of the polarization. Methods. We studied the polarization signatures resulting from the prolate structure of rotating winds of two WR stars using a 3D Monte Carlo radiative transfer code Hyperion. We estimated the intrinsic polarization resulting from multiple-scattering in WR winds for different rotational velocities, inclination angles, and mass-loss rates. Results. Our results indicate that at a rotation rate of less than 50% of the critical rate, the intrinsic polarization from multiplescattering is close to that of a single-scattering model. However, at higher rotation velocities, the polarization from multiple-scattering increases with inclination up to 40 degrees, while it decreases for inclinations higher than about 60 degrees. This dependence is inconsistent with the single-scattering model. We also discuss the effect of the mass-loss rate on the polarization and find that the polarization changes linearly with the mass-loss rate. However, it is important to note that the relationship between polarization and mass-loss rate may vary for different types of stars. Conclusions. The results have implications for future studies of stellar winds and mass loss and may help to improve our understanding of the complex environments of massive stars. Our research offers valuable information on the complex polarization patterns observed in stellar winds, emphasizing the significance of accounting for the influence of multiple-scattering when interpreting observations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GA25-15910S" target="_blank" >GA25-15910S: Větry horkých hvězd: řešení nejistot ztráty hmoty v blízkosti Eddingtonovy limity</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

698

Číslo periodika v rámci svazku

June

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

6

Strana od-do

A225

Kód UT WoS článku

001510826300030

EID výsledku v databázi Scopus

2-s2.0-105008813105