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تسجيل مستخدم جديدThe optically thick rotating magnetic wind from a massive white dwarf merger product
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WD J005311 is a newly identified white dwarf (WD) in a mid-infrared nebula. The spectroscopic observation indicates the existence of a neon-enriched carbon/oxygen wind with a terminal velocity of $v_{infty,rm obs}sim 16,000,rm km,s^{-1}$ and a mass loss rate of $dot M_{rm obs}sim 3.5times 10^{-6},M_odot$ yr$^{-1}$. Here we consistently explain the properties of WD J005311 using a newly constructed wind solution, where the optically thick outflow is launched from the carbon burning shell on an oxygen-neon core and accelerated by the rotating magnetic field to become supersonic and unbound well below the photosphere. Our model implies that WD J005311 has a mass of $M_* sim 1.1mbox{-}1.3,M_odot$, a magnetic field of $B_* sim (2mbox{-}5)times 10^7,rm G$, and a spin angular frequency of $Omega sim 0.2mbox{-}0.5 ,rm s^{-1}$. The large magnetic field and fast spin support the carbon-oxygen WD merger origin. WD J005311 will neither explode as a type Ia supernova nor collapse into a neutron star. If the wind continues to blow another few kyr, WD J005311 will spin down significantly and join to the known sequence of slowly-rotating magnetic WDs. Otherwise it may appear as a fast-spinning magnetic WD and could be a new high energy source.
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About 10% of stars more massive than ${approx},1.5,mathrm{M}_odot$ have strong, large-scale surface magnetic fields and are being discussed as progenitors of highly-magnetic white dwarfs and magnetars. The origin of these fields remains uncertain. Re
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We analyze time-series spectroscopy of the white dwarf merger candidate J005311 and confirm the unique nature of its optical spectrum. We detect an additional broad emission feature peaking at 343nm that was predicted in the Gvaramadze et al. (2019;
arXiv:1904.00012) models. Comparing ten spectra taken with the Large Binocular Telescope (LBT), we find significant variability in the profile of the strong OVI 381.1/383.4nm emission feature. This appears to be caused by rapidly shifting subpeaks generated by clumpiness in the stellar wind of J005311. This line variability is similar to what is seen in many Wolf-Rayet stars. However, in J005311, the rate of motion of the subpeaks appears exceedingly high as they can reach 16000 km/s in less than two hours.
White dwarfs represent the last stage of evolution of stars with mass less than about eight times that of the Sun and, like other stars, are often found in binaries. If the orbital period of the binary is short enough, energy losses from gravitationa
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