Testing a scaling relation between coherent radio emission and physical parameters of hot magnetic stars

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F22%3A00128184" target="_blank" >RIV/00216224:14310/22:00128184 - isvavai.cz</a>

Výsledek na webu

<a href="https://academic.oup.com/mnras/article/517/4/5756/6780209" target="_blank" >https://academic.oup.com/mnras/article/517/4/5756/6780209</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/mnras/stac3123" target="_blank" >10.1093/mnras/stac3123</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Testing a scaling relation between coherent radio emission and physical parameters of hot magnetic stars

Popis výsledku v původním jazyce

Coherent radio emission via electron cyclotron maser emission (ECME) from hot magnetic stars was discovered more than two decades ago, but the physical conditions that make the generation of ECME favourable remain uncertain. Only recently was an empirical relation, connecting ECME luminosity with the stellar magnetic field and temperature, proposed to explain what makes a hot magnetic star capable of producing ECME. This relation was, however, obtained with just 14 stars. Therefore, it is important to examine whether this relation is robust. With the aim of testing the robustness, we conducted radio observations of five hot magnetic stars. This led to the discovery of three more stars producing ECME. We find that the proposed scaling relation remains valid after the addition of the newly discovered stars. However, we discovered that the magnetic field and effective temperature correlate for T-eff less than or similar to 16 kK (likely an artefact of the small sample size), rendering the proposed connection between ECME luminosity and T-eff unreliable. By examining the empirical relation in light of the scaling law for incoherent radio emission, we arrive at the conclusion that both types of emission are powered by the same magnetospheric phenomenon. Like the incoherent emission, coherent radio emission is indifferent to T-eff for late-B and A-type stars, but T-eff appears to become important for early-B type stars, possibly due to higher absorption, or higher plasma density at the emission sites suppressing the production of the emission.

Název v anglickém jazyce

Testing a scaling relation between coherent radio emission and physical parameters of hot magnetic stars

Popis výsledku anglicky

Coherent radio emission via electron cyclotron maser emission (ECME) from hot magnetic stars was discovered more than two decades ago, but the physical conditions that make the generation of ECME favourable remain uncertain. Only recently was an empirical relation, connecting ECME luminosity with the stellar magnetic field and temperature, proposed to explain what makes a hot magnetic star capable of producing ECME. This relation was, however, obtained with just 14 stars. Therefore, it is important to examine whether this relation is robust. With the aim of testing the robustness, we conducted radio observations of five hot magnetic stars. This led to the discovery of three more stars producing ECME. We find that the proposed scaling relation remains valid after the addition of the newly discovered stars. However, we discovered that the magnetic field and effective temperature correlate for T-eff less than or similar to 16 kK (likely an artefact of the small sample size), rendering the proposed connection between ECME luminosity and T-eff unreliable. By examining the empirical relation in light of the scaling law for incoherent radio emission, we arrive at the conclusion that both types of emission are powered by the same magnetospheric phenomenon. Like the incoherent emission, coherent radio emission is indifferent to T-eff for late-B and A-type stars, but T-eff appears to become important for early-B type stars, possibly due to higher absorption, or higher plasma density at the emission sites suppressing the production of the emission.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

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

Název periodika

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

e-ISSN

1365-2966

Svazek periodika

517

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

14

Strana od-do

5756-5769

Kód UT WoS článku

000881809100032

EID výsledku v databázi Scopus

2-s2.0-85145351490