Modeling variability of Be stars

D 2019

Modeling variability of Be stars

KURFÜRST, Petr a Jiří KRTIČKA

Základní údaje

Originální název

Modeling variability of Be stars

Autoři

KURFÜRST, Petr a Jiří KRTIČKA

Vydání

Neuveden, Proceedings of the 50thConference on Variable Stars Research, od s. 43-49, 7 s. 2019

Nakladatel

Open European Journal on Variable Stars

Další údaje

Jazyk

angličtina

Typ výsledku

Stať ve sborníku

Obor

10308 Astronomy

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Forma vydání

elektronická verze "online"

Odkazy

URL

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/19:00107398

Organizační jednotka

Přírodovědecká fakulta

ISSN

Klíčová slova anglicky

Be stars; Be disks; variability; BeX-ray binaries; accretion rate

Štítky

rivok

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 18. 4. 2020 12:31, Mgr. Ing. arch. Petr Kurfürst, Ph.D.

Anotace

V originále

Be stars are rapidly rotating non-supergiant B-type stars surrounded by equatorial Keplerian disks. The characteristic property of all Be stars is their multiperiodic variability driven for example by pulsations in isolated Be stars or by the effects of binarity. We assume in our models the equatorial decretion disk that stems from the angular momentum loss needed to keep the central object at or below the critical rotation. Using our hydrodynamic code, we calculate the 2D profile of Be stars’ disk structure under various physical and geometrical configurations of the star-disk system as well as various profiles of the circumstellar medium. The tidal interactions in binary systems facilitate the matter ejection from the equatorial region of the star, and there is also evidence of warping of the disk in binaries. The important subclass is the Be/X-ray binaries, consisting of a Be star and mostly a neutron star (NS), which belong to the brightest objects in the X-ray sky. Intensive matter accretion from the optical donor companion onto the compact object in a relatively close binary system produces transient phases of the high energy X-ray emission which dramatically vary in brightness and whose timescales may range from milliseconds to years. We calculate the effects of X-ray irradiation on the temperature structure of the Be stars’ disk. Using the Bondi-Hoyle-Littleton approximation, we estimate the NS accretion rate and the excess of X-ray luminosity during various phases of NS-disk interaction.

Návaznosti

GA16-01116S, projekt VaV

Název: Atmosféry a okolohvězdné prostředí magnetických horkých hvězd

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

LM2010005, projekt VaV

Název: Velká infrastruktura CESNET (Akronym: VI CESNET)

Investor: Ministerstvo školství, mládeže a tělovýchovy ČR, Velká infrastruktura CESNET

Citovat

KURFÜRST, Petr a Jiří KRTIČKA. Modeling variability of Be stars. Online. In Radek Kocián. Proceedings of the 50thConference on Variable Stars Research. Neuveden: Open European Journal on Variable Stars, 2019, s. 43-49. ISSN 1801-5964.

@inproceedings{1530617,
   author = {Kurfürst, Petr and Krtička, Jiří},
   address = {Neuveden},
   booktitle = {Proceedings of the 50thConference on Variable Stars Research},
   editor = {Radek Kocián},
   keywords = {Be stars; Be disks; variability; BeX-ray binaries; accretion rate},
   howpublished = {elektronická verze "online"},
   language = {eng},
   location = {Neuveden},
   pages = {43-49},
   publisher = {Open European Journal on Variable Stars},
   title = {Modeling variability of Be stars},
   url = {http://var.astro.cz/oejv/issues/oejv0197.pdf},
   year = {2019}
}

TY  - CONF
ID  - 1530617
AU  - Kurfürst, Petr - Krtička, Jiří
PY  - 2019
TI  - Modeling variability of Be stars
PB  - Open European Journal on Variable Stars
CY  - Neuveden
KW  - Be stars
KW  - Be disks
KW  - variability
KW  - BeX-ray binaries
KW  - accretion rate
UR  - http://var.astro.cz/oejv/issues/oejv0197.pdf
L2  - http://var.astro.cz/oejv/issues/oejv0197.pdf
N2  - Be stars are rapidly rotating non-supergiant B-type stars surrounded by equatorial Keplerian disks. The characteristic property of all Be stars is their multiperiodic variability driven for example by pulsations in isolated Be stars or by the effects of binarity. We assume in our models the equatorial decretion disk that stems from the angular momentum loss needed to keep the central object at or below the critical rotation. Using our hydrodynamic code, we calculate the 2D profile of Be stars’ disk structure under various physical and geometrical configurations of the star-disk system as well as various profiles of the circumstellar medium. The tidal interactions in binary systems facilitate the matter ejection from the equatorial region of the star, and there is also evidence of warping of the disk in binaries. The important subclass is the Be/X-ray binaries, consisting of a Be star and mostly a neutron star (NS), which belong to the brightest objects in the X-ray sky. Intensive matter accretion from the optical donor companion onto the compact object in a relatively close binary system produces transient phases of the high energy X-ray emission which dramatically vary in brightness and whose timescales may range from milliseconds to years. We calculate the effects of X-ray irradiation on the temperature structure of the Be stars’ disk. Using the Bondi-Hoyle-Littleton approximation, we estimate the NS accretion rate and the excess of X-ray luminosity during various phases of NS-disk interaction.
ER  -

KURFÜRST, Petr a Jiří KRTIČKA. Modeling variability of Be stars. Online. In Radek Kocián. \textit{Proceedings of the 50thConference on Variable Stars Research}. Neuveden: Open European Journal on Variable Stars, 2019, s.~43-49. ISSN~1801-5964.

Přehled o publikaci