Polarimetric evidence of a white dwarf pulsar in the binary system AR Scorpii
arXiv:1612.03185 · doi:10.1038/s41550-016-0029
Abstract
The variable star AR Sco was recently discovered to pulse in brightness every 1.97 min from ultraviolet wavelengths into the radio regime. The system is composed of a cool, low-mass star in a tight, 3.55 hr orbit with a more massive white dwarf. Here we report new optical observations of AR Sco that show strong linear polarization (up to 40%) which varies strongly and periodically on both the spin period of the white dwarf and the beat period between the spin and orbital period, as well as low level (< a few %) circular polarization. These observations support the notion that, similar to neutron star pulsars, the pulsed luminosity of AR Sco is powered by the spin-down of the rapidly-rotating white dwarf which is highly magnetised (up to 500 MG). The morphology of the modulated linear polarization is similar to that seen in the Crab pulsar, albeit with a more complex waveform owing to the presence of two periodic signals of similar frequency. Magnetic interactions between the two component stars, coupled with synchrotron radiation from the white dwarf, power the observed polarized and non-polarized emission. AR Scorpii is therefore the first example of a white dwarf pulsar.
21 pages, 4 figures, 1 supplementary table, 8 supplementary figures
References in corpus (7)
- Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
- Magnetic White Dwarfs
- A radio pulsing white dwarf binary star
- Optical polarisation of the Crab pulsar: precision measurements and comparison to the radio emission
- AR Sco: A White Dwarf Synchronar
- Circular polarization survey of intermediate polars I. Northern targets in the range 17h<R.A.<23h
- Circular polarisation of synchrotron radiation in high magnetic fields
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