By simulating the suggestions of the white dwarf (WD) to the periodic mass switch pushed by the X-ray irradiation on its companion, researchers led by Ph.D. candidate Zhao Weitao and Prof. Meng Xiangcun from the Yunnan Observatories of the Chinese language Academy of Sciences have reproduced the quasi-periodic gentle curve of the supersoft X-ray supply, which gives a brand new approach to clarify its origin.
Associated outcomes have been revealed in Astronomy and Astrophysics on Oct. 7.
Sort Ia supernovae at the moment are getting used as normal candles to measure cosmological parameters and thus look at the evolution of the darkish vitality equation of state with time. Supersoft X-ray sources are thought-about the more than likely progenitor objects for kind Ia supernovae.
A supersoft X-ray supply consists of a WD and an enormous main-sequence companion star. The WD accretes supplies from its companion star and will increase its mass till it reaches the Chandrasekhar mass restrict, inflicting a sort Ia supernova explosion.
The sunshine curves of supersoft X-ray sources present a quasi-periodic variability of lightness and darkness. Nevertheless, the rationale of such quasi-periodic variation of the sunshine curve of supersoft X-ray sources remains to be unclear.
Earlier research on this quasi-periodic gentle curve ignored the impact of supersoft X-rays on the companion star. The X-ray irradiation is predicted to warmth the companion star and alter its efficient floor boundary situation, which then attenuates the mass switch price of the binary system.
On this examine, the researchers proposed periodically irradiating the companion star by the supersoft X-rays, which is able to trigger it to develop and contract. In consequence, the binary mass switch price will increase and reduces periodically.
They used Modules for Experiments in Stellar Astrophysics (MESA) code to hold out 1D simulations, and adopted a periodic jagged accretion price onto the WD as an alternative of the periodic variability within the mass switch price.
Attributable to periodic variability of the mass accretion price onto the WD, the WD photosphere periodically expands and contracts, which properly reproduces the sunshine curve of the supersoft X-ray supply.
Weitao Zhao et al, A sturdy mannequin for the origin of optical quasi-periodic variability in supersoft X-ray sources, Astronomy & Astrophysics (2022). DOI: 10.1051/0004-6361/202243759
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Exploring the origin of the supersoft X-ray gentle curve (2022, October 14)
retrieved 14 October 2022
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