Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation

In this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed b...

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Main Authors: Dmitry Bisikalo, Andrey Sobolev, Andrey Zhilkin
Format: Article
Language:English
Published: MDPI AG 2021-11-01
Series:Galaxies
Subjects:
Online Access:https://www.mdpi.com/2075-4434/9/4/110
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author Dmitry Bisikalo
Andrey Sobolev
Andrey Zhilkin
author_facet Dmitry Bisikalo
Andrey Sobolev
Andrey Zhilkin
author_sort Dmitry Bisikalo
collection DOAJ
description In this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed based on the results of numerical calculations and maps of the temperature distribution over the accretor surface. It is shown that a noticeable displacement of the spots is determined by the ratio of ballistic and magnetic parts of the jet trajectory. In the synchronous polar, the dominant influence on the drift of hot spots is exerted by variations in the mass transfer rate, which entail a change in the ballistic part of the trajectory. It was found that when the mass transfer rate changes within the range of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><msub><mi>M</mi><mo>⊙</mo></msub><mo>/</mo><mi>year</mi></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><msub><mi>M</mi><mo>⊙</mo></msub><mo>/</mo><mi>year</mi></mrow></semantics></math></inline-formula>, the displacement of the hot spot in latitude and longitude can reach <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>30</mn><mo>∘</mo></msup></semantics></math></inline-formula>. In the asynchronous polar, a change in the position of hot spots is mainly defined by the properties of the white dwarf magnetosphere, and the displacement of hot spots in latitude and longitude can reach <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>20</mn><mo>∘</mo></msup></semantics></math></inline-formula>.
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spelling doaj.art-0648c46b4c394655a6ae4e9d34ea65002023-11-23T08:26:21ZengMDPI AGGalaxies2075-44342021-11-019411010.3390/galaxies9040110Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical SimulationDmitry Bisikalo0Andrey Sobolev1Andrey Zhilkin2Institute of Astronomy of the Russian Academy of Sciences, 48 Pyatnitskaya St., 119017 Moscow, RussiaInstitute of Astronomy of the Russian Academy of Sciences, 48 Pyatnitskaya St., 119017 Moscow, RussiaInstitute of Astronomy of the Russian Academy of Sciences, 48 Pyatnitskaya St., 119017 Moscow, RussiaIn this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed based on the results of numerical calculations and maps of the temperature distribution over the accretor surface. It is shown that a noticeable displacement of the spots is determined by the ratio of ballistic and magnetic parts of the jet trajectory. In the synchronous polar, the dominant influence on the drift of hot spots is exerted by variations in the mass transfer rate, which entail a change in the ballistic part of the trajectory. It was found that when the mass transfer rate changes within the range of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><msub><mi>M</mi><mo>⊙</mo></msub><mo>/</mo><mi>year</mi></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><msub><mi>M</mi><mo>⊙</mo></msub><mo>/</mo><mi>year</mi></mrow></semantics></math></inline-formula>, the displacement of the hot spot in latitude and longitude can reach <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>30</mn><mo>∘</mo></msup></semantics></math></inline-formula>. In the asynchronous polar, a change in the position of hot spots is mainly defined by the properties of the white dwarf magnetosphere, and the displacement of hot spots in latitude and longitude can reach <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>20</mn><mo>∘</mo></msup></semantics></math></inline-formula>.https://www.mdpi.com/2075-4434/9/4/110close binary starpolarMHDflow structuredonoraccretor
spellingShingle Dmitry Bisikalo
Andrey Sobolev
Andrey Zhilkin
Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation
Galaxies
close binary star
polar
MHD
flow structure
donor
accretor
title Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation
title_full Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation
title_fullStr Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation
title_full_unstemmed Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation
title_short Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation
title_sort hot spots drift in synchronous and asynchronous polars results of three dimensional numerical simulation
topic close binary star
polar
MHD
flow structure
donor
accretor
url https://www.mdpi.com/2075-4434/9/4/110
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AT andreysobolev hotspotsdriftinsynchronousandasynchronouspolarsresultsofthreedimensionalnumericalsimulation
AT andreyzhilkin hotspotsdriftinsynchronousandasynchronouspolarsresultsofthreedimensionalnumericalsimulation