Equation of state and surface thermal emission of magnetized white dwarfs

Gao, Zhi; Wang, Hui; Zhao, Xin Jun; Yang, Xiao feng

doi:10.1002/asna.20220112

Cited by 3 publications

(3 citation statements)

References 28 publications

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“…In addition, there may be many other factors affecting the formation path and evolution state of variable stars; for example, overshooting [98]. Convective overshoot is not only related to the formation and evolution of pulsating variablestars but also associated with many important celestial bodies and extreme physical processes, such as massive pulsating variable stars [99], white dwarfs [100], X-ray binaries [101], and high-magnetic pulsars [102,103].…”

Section: Pulsation Constant Of Cepheidmentioning

confidence: 99%

Parameters and Pulsation Constant of Cepheid

Sinitsyn

2023

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The analysis of fifty empirical period-radius relations and forty-three empirical period-luminosity relations is performed for the Cepheids. It is found that most of these relations have significant systematic errors. A new metrological method is suggested to exclude these systematic errors using the new empirical metrological relations and the empirical temperature scale of the various samples of the Cepheids. In this regard, the reliable relations between the mass, radius, effective surface temperature, luminosity, absolute magnitude on the one hand, and the pulsation period on the other hand, as well as the reliable dependence of the radius on the mass are determined for the Cepheids of types δ Cephei and δ Scuti from the Galaxy. These reliable relations permit us to accurately determine the empirical value of the pulsation constant for the Cepheids of both types for the first time. It is found that the pulsation constant very weakly depends on the pulsation period of the Cepheid, contrary to the known theoretical calculation. Hence, the Cepheids pulsate almost as a unified whole and homogeneous spherical body in wide ranges of a star’s mass and evolutionary state with an extremely inhomogeneous distribution of stellar substance over its volume. Therefore, it is first suggested that the pulsation of the Cepheid is, first of all, the pulsation of the almost unified whole and homogenous shell of its gravitational mass. This pulsation is triggered by well-known effects; for example, the local optical opacity of the stellar substance and overshooting, using the usual pulsation of the stellar substance.

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Section: Pulsation Constant Of Cepheidmentioning

confidence: 99%

Parameters and Pulsation Constant of Cepheid

Sinitsyn

2023

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“…Their radiation decreases over time from the initial high color temperature to turn red. Some observations show that the effective temperature of WDs may be mostly between 5500 K -40000 K (e.g., Gao et al 2023), and a few are outside this range, and the total thermal energy may be less than 10 47 erg. What are the specific heat sources in WDs?…”

Section: Introductionmentioning

confidence: 99%

“…We studied the problem of MMs and other related issues (e.g., Peng et al 2017Peng et al , 2020Liu 2013Liu , 2014Liu & Gu 2016a;Liu & Liu 2017c, 2018aLiu 2016b;Liu & Liu 2016c;Liu 2016d;Liu et al 2017aLiu et al , 2017bLiu & Liu 2018b). Some scholars also discussed other energy mechanisms of WDs, such as magnetic field evolution, the state equation of the WDs and related issues (e.g., Deng et al 2020Deng et al , 2021Li et al 2016;Fu et al 2020;Gao et al 2016Gao et al , 2017Gao et al , 2019Gao et al , 2023Dong et al 2023;Wang et al 2020;Yan et al 2021;Zhu et al 2016). Their researches provide a database for further exploration of the evolution of WDs.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Velocity-dependent Correction Factor on Proton Decay Reactions in Massive White Dwarfs

Liu,

Liu

2024

Res. Astron. Astrophys.

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25 typical super-massive white dwarfs (WDs) are selected and the proton decay reaction Catalyzed by magnetic monopoles (MMs) for WDs is discussed. The main highlights are given as follows. Firstly, by considering the effect of the temperature on cross section and the thermonuclear reaction and mass-radius relationship, we present two new the MMs models (I, II) to discuss the energy resources problem based on MMs catalytic nuclear decay (i.e.,RC effect). Secondly, we detailed calculate the the number of MMs captured by WDs and compare the luminosity with the observations. Finally, we discuss the effect of the correction factor on the cross section for the Rubakov process in model (II) and the differences of the WDs luminosities between the two models are shown. We find that a strong suppression control the monopole catalysis of nucleon decay. The maximum of the the number of MMs captured and the luminosity can be $2.235\times10^{21}$ , and $1.7859\times10^{32}\rm{ergs^{-1}}$, respectively (e.g., for O+Ne core mass WD J055631.17+130639.78). The luminosities for most of massive WDs are agreed well with the observations at relativistic low temperature (e.g., $T_6=0.1$), but can be three, and two orders magnitude higher than those of the observations for model (I), and (II) at relativistic high temperature (e.g., $T_6=10$), respectively. The luminosities for model (I) are about one order magnitude higher than those of model (II) in the same astrophysical environment. Due to consider the affect of the number of the MMs captured on the mass radius relationship and the suppression on the proton decay from the correction factor, the study in the model (II) may be an improving estimation.

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Dirac spinor scattering states with positive‐energy in rotating spheroid models

Gao,

Chen,

Wang

et al. 2024

Astron Nachr

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There are many rotating spheroids in the universe, and many astronomers and physicists have used theoretical methods to study the characteristics of stellar gravity since Newton's time. This paper derives the solutions of eight scattering states ,, and for the Dirac equation with positive‐energy , and establishes the relationship between the differential scattering cross section and the stellar density . It is found that: (1) For the eight scattering states, their average scattering cross‐sections are proportional to , and depend on the star's radius, and the higher the stellar density , the greater the sensitivity of to the change of ; (2) For the four scattering states , their average scattering amplitudes and depend on the mass of the particles; while for the other four scattering states , , then and are independent of . This study links the gravitational characteristics of stars with the scattering cross section, creating a new method for studying the gravitational characteristics, which helps to reveal the mystery of the gravity of rotating ellipsoidal stars.

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Equation of state and surface thermal emission of magnetized white dwarfs

Cited by 3 publications

References 28 publications

Parameters and Pulsation Constant of Cepheid

Parameters and Pulsation Constant of Cepheid

The Influence of Velocity-dependent Correction Factor on Proton Decay Reactions in Massive White Dwarfs

Dirac spinor scattering states with positive‐energy in rotating spheroid models

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