The nature of the light variability of magnetic Of?p star HD
191612

J 2016

The nature of the light variability of magnetic Of?p star HD 191612

KRTIČKA, Jiří

Základní údaje

Originální název

The nature of the light variability of magnetic Of?p star HD 191612

Autoři

KRTIČKA, Jiří (203 Česká republika, garant, domácí)

Vydání

Astronomy and Astrophysics, EDP Sciences, 2016, 0004-6361

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10308 Astronomy

Stát vydavatele

Francie

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Impakt faktor

Impact factor: 4.378 v roce 2014

Kód RIV

RIV/00216224:14310/16:00088249

Organizační jednotka

Přírodovědecká fakulta

DOI

http://dx.doi.org/10.1051/0004-6361/201629222

UT WoS

000385832200121

Klíčová slova česky

hvězdné větry, ztráta hmoty, proměnné hvězdy, hydrodynamika

Klíčová slova anglicky

stars winds outflows; stars mass-loss; stars early-type; stars variables general; hydrodynamics

Štítky

AKR, rivok

Příznaky

Recenzováno

Změněno: 14. 4. 2017 15:05, Ing. Andrea Mikešková

Anotace

V originále

A small fraction of hot OBA stars host global magnetic fields with field strengths of the order of 0.1-10 kG. This leads to the creation of persistent surface structures (spots) in stars with sufficiently weak winds as a result of the radiative diffusion. These spots become evident in spectroscopic and photometric variability. This type of variability is not expected in stars with strong winds, where the wind inhibits the radiative diffusion. Therefore, a weak photometric variability of the magnetic Of?p star HD 191612 is attributed to the light absorption in the circumstellar clouds. We study the nature of the photometric variability of HD 191612. We assume that the variability results from variable wind blanketing induced by surface variations of the magnetic field tilt and modulated by stellar rotation. We used our global kinetic equilibrium (NLTE) wind models with radiative force determined from the radiative transfer equation in the comoving frame (CMF) to predict the stellar emergent flux. Our models describe the stellar atmosphere in a unified manner and account for the influence of the wind on the atmosphere. The models are calculated for different wind mass-loss rates to mimic the effect of magnetic field tilt on the emergent fluxes. We integrate the emergent fluxes over the visible stellar surface for individual rotational phases, and calculate the rotationally modulated light curve of HD 191612. The wind blanketing that varies across surface of HD 191612 is able to explain a part of the observed light variability in this star. The mechanism is able to operate even at relatively low mass-loss rates. The remaining variability is most likely caused by the flux absorption in circumstellar clouds. The variable wind blanketing is an additional source of the light variability in massive stars. The presence of the rotational light variability may serve as a proxy for the magnetic field.

Návaznosti

GA16-01116S, projekt VaV

Název: Atmosféry a okolohvězdné prostředí magnetických horkých hvězd

Investor: Grantová agentura ČR, Atmosféry a okolohvězdné prostředí magnetických horkých hvězd

Citovat

KRTIČKA, Jiří. The nature of the light variability of magnetic Of?p star HD 191612. Astronomy and Astrophysics. EDP Sciences, 2016, roč. 594, october, s. "nestrankovano", 4 s. ISSN 0004-6361. Dostupné z: https://dx.doi.org/10.1051/0004-6361/201629222.

@article{1357305,
   author = {Krtička, Jiří},
   article_number = {october},
   doi = {http://dx.doi.org/10.1051/0004-6361/201629222},
   keywords = {stars winds outflows; stars mass-loss; stars early-type; stars variables general; hydrodynamics},
   language = {eng},
   issn = {0004-6361},
   journal = {Astronomy and Astrophysics},
   title = {The nature of the light variability of magnetic Of?p star HD 191612},
   url = {http://adsabs.harvard.edu/abs/2016A%26A...594A..75K},
   volume = {594},
   year = {2016}
}

TY  - JOUR
ID  - 1357305
AU  - Krtička, Jiří
PY  - 2016
TI  - The nature of the light variability of magnetic Of?p star HD 191612
JF  - Astronomy and Astrophysics
VL  - 594
IS  - october
SP  - "nestrankovano"
EP  - "nestrankovano"
PB  - EDP Sciences
SN  - 00046361
KW  - stars winds outflows
KW  - stars mass-loss
KW  - stars early-type
KW  - stars variables general
KW  - hydrodynamics
UR  - http://adsabs.harvard.edu/abs/2016A%26A...594A..75K
N2  - A small fraction of hot OBA stars host global magnetic fields with field strengths of the order of 0.1-10 kG. This leads to the creation of persistent surface structures (spots) in stars with sufficiently weak winds as a result of the radiative diffusion. These spots become evident in spectroscopic and photometric variability. This type of variability is not expected in stars with strong winds, where the wind inhibits the radiative diffusion. Therefore, a weak photometric variability of the magnetic Of?p star HD 191612 is attributed to the light absorption in the circumstellar clouds. We study the nature of the photometric variability of HD 191612. We assume that the variability results from variable wind blanketing induced by surface variations of the magnetic field tilt and modulated by stellar rotation. We used our global kinetic equilibrium (NLTE) wind models with radiative force determined from the radiative transfer equation in the comoving frame (CMF) to predict the stellar emergent flux. Our models describe the stellar atmosphere in a unified manner and account for the influence of the wind on the atmosphere. The models are calculated for different wind mass-loss rates to mimic the effect of magnetic field tilt on the emergent fluxes. We integrate the emergent fluxes over the visible stellar surface for individual rotational phases, and calculate the rotationally modulated light curve of HD 191612. The wind blanketing that varies across surface of HD 191612 is able to explain a part of the observed light variability in this star. The mechanism is able to operate even at relatively low mass-loss rates. The remaining variability is most likely caused by the flux absorption in circumstellar clouds. The variable wind blanketing is an additional source of the light variability in massive stars. The presence of the rotational light variability may serve as a proxy for the magnetic field.
ER  -

KRTIČKA, Jiří. The nature of the light variability of magnetic Of?p star HD 191612. \textit{Astronomy and Astrophysics}. EDP Sciences, 2016, roč.~594, october, s.~''nestrankovano'', 4 s. ISSN~0004-6361. Dostupné z: https://dx.doi.org/10.1051/0004-6361/201629222.

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