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The unique binary AR Scorpii consists of an asynchronously rotating, magnetized white dwarf (WD) that interacts with its red-dwarf companion to produce a large-amplitude, highly coherent pulsation every 1.97 minutes. Over the course of two…

Solar and Stellar Astrophysics · Physics 2018-09-19 Robert A. Stiller , Colin Littlefield , Peter Garnavich , Charlotte Wood , Franz-Josef Hambsch , Gordon Myers

A 3.56-hour white dwarf (WD) - M dwarf (MD) close binary system, AR Scorpii, was recently reported to show pulsating emission in radio, IR, optical, and UV, with a 1.97-minute period, which suggests the existence of a WD with a rotation…

High Energy Astrophysical Phenomena · Physics 2017-05-11 Jin-Jun Geng , Bing Zhang , Yong-Feng Huang

AR Scorpii (AR Sco) is the only radio-pulsing white dwarf known to date. It shows a broad-band spectrum extending from radio to X-rays whose luminosity cannot be explained by thermal emission from the system components alone, and is instead…

The compact object in the interacting binary AR Sco has widely been presumed to be a rapidly rotating, magnetized white dwarf (WD), but it has never been detected directly. Isolating its spectrum has proven difficult because the spin-down…

Solar and Stellar Astrophysics · Physics 2021-03-03 Peter Garnavich , Colin Littlefield , Maxim Lyutikov , Maxim Barkov

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…

High Energy Astrophysical Phenomena · Physics 2017-01-26 D. A. H. Buckley , P. J. Meintjes , S. B. Potter , T. R. Marsh , B. T Gänsicke

Radio pulsating white dwarf (WD) systems, known as WD pulsars, are non-accreting binary systems where the rapidly spinning WD interacts with a low-mass companion producing pulsed non-thermal emission that can be observed across the entire…

We present high-speed optical photometric observations, spanning ~2 years, of the recently-discovered white dwarf pulsar AR Scorpii. The amplitudes of the orbital, spin and beat modulations appear to be remarkably stable and repeatable over…

High Energy Astrophysical Phenomena · Physics 2018-05-16 Stephen B. Potter , David A. H. Buckley

White dwarfs are compact stars, similar in size to Earth but ~200,000 times more massive. Isolated white dwarfs emit most of their power from ultraviolet to near-infrared wavelengths, but when in close orbits with less dense stars, white…

We present detailed optical photo-polarimetric observations of the recently-discovered white dwarf pulsar AR Scorpii. Our extensive dataset reveals that the polarized emission is remarkably stable and repeatable with spin, beat and orbital…

High Energy Astrophysical Phenomena · Physics 2018-09-12 Stephen B. Potter , David A. H. Buckley

AR Scorpii is unique amongst known white dwarf binaries in showing powerful pulsations extending to radio frequencies. Here we aim to investigate the multi-frequency radio emission of AR Sco in detail, in order to constrain its origin and…

Solar and Stellar Astrophysics · Physics 2018-03-28 E. R. Stanway , T. R. Marsh , P. Chote , B. T. Gaensicke , D. Steeghs , P. J. Wheatley

Marsh et al. (2016) have recently reported the discovery of a radio-pulsing white dwarf in the cataclysmic variable AR Sco. The period of pulsations which are also seen in the optical and UV is about 117 seconds. High intensity of pulsing…

High Energy Astrophysical Phenomena · Physics 2016-12-26 N. G. Beskrovnaya , N. R. Ikhsanov

We obtained high temporal resolution spectroscopy of the unusual binary system AR Sco covering nearly an orbit. The H$\alpha$ emission shows a complex line structure similar to that seen in some polars during quiescence. Such emission is…

Solar and Stellar Astrophysics · Physics 2019-02-20 Peter Garnavich , Colin Littlefield , Stella Kafka , Mark Kennedy , Paul Callanan , Dinshaw Balsara , Maxim Lyutikov

Marsh et al. detected radio and optical pulsations from the binary system AR Scorpii (AR Sco). This system, with an orbital period of 3.56 h, is composed of a cool, low-mass star and a white dwarf with a spin period of 1.95 min. Optical…

High Energy Astrophysical Phenomena · Physics 2019-07-03 L. du Plessis , Z. Wadiasingh , C. Venter , A. K. Harding , S. Chandra , P. J. Meintjies

The discovery of the white dwarf binary system AR Scorpii (AR Sco) with its fascinating non-thermal dominated multi-frequency emission has sparked renewed interest in potential high energy gamma-ray emission from white dwarf pulsars. The…

High Energy Astrophysical Phenomena · Physics 2019-08-02 Q. Kaplan , P. J. Meintjes , K. K. Singh , H. J. van Heerden , F. A. Ramamonjisoa , I. P. van der Westhuizen

The binary system AR Scorpii hosts an M-type main sequence cool star orbiting around a magnetic white dwarf in the Milky Way Galaxy. The broadband non-thermal emission over radio, optical and X-ray wavebands observed from AR Scorpii…

High Energy Astrophysical Phenomena · Physics 2021-05-12 K. K. Singh , P. J. Meintjes , K. K. Yadav

AR~Scorpii is an intermediate polar system composed of a magnetic white dwarf (WD) and an M-type star, and shows non-thermal, pulsed, and highly linearly polarized emission. The radio/optical emission modulates with the WD's spin and show…

High Energy Astrophysical Phenomena · Physics 2017-12-27 J. Takata , H. Yang , K. S. Cheng

In view of the new recent observation and measurement of the rotating and highly-magnetized white dwarf AR Scorpii \cite{Marsh:2016uhc}, we determine bounds of its moment of inertia, magnetic fields and radius. Moreover, we investigate the…

Solar and Stellar Astrophysics · Physics 2017-03-23 B. Franzon , S. Schramm

White dwarf stars are the most common stellar fossils. When in binaries, they make up the dominant form of compact object binary within the Galaxy and can offer insight into different aspects of binary formation and evolution. One of the…

We analyze rapid-cadence, multiwavelength photometry of AR Scorpii from three observatories, covering five observing seasons. We measure the arrival times of the system's beat pulses and use them to compute an updated ephemeris. The white…

Solar and Stellar Astrophysics · Physics 2020-07-31 Yadira Gaibor , Peter Garnavich , Colin Littlefield , Stephen B. Potter , David A. H. Buckley

AR Scorpii (AR Sco), the only-known radio-pulsing white dwarf binary, shows unusual pulsating emission at the radio, infrared, optical and ultraviolet bands. To determine its astrometric parameters at the radio band independently, we…

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