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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

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

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 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

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…

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

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…

After its discovery in 2016, the white dwarf binary AR Scorpii (AR Sco) remained for several years the only white dwarf system to show pulsed radio emission associated with a fast-spinning white dwarf. The evolutionary origin and the…

In this work, we have analyzed the $\gamma$-ray data in the energy range 100 MeV to 500 GeV from the \emph{Fermi}-Large Area Telescope (LAT) observations for the period August 4, 2008 to March 31, 2019. The $\gamma$-ray emission from AR…

High Energy Astrophysical Phenomena · Physics 2020-07-15 K. K. Singh , P. J. Meintjes , Q. Kaplan , F. A. Ramamonjisoa , S. Sahayanathan

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

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…

AR Sco is a binary system that contains a white and red dwarf. The rotation rate of the white dwarf has been observed to slow down, analogous to rotation-powered radio pulsars; it has thus been dubbed a "white dwarf pulsar". We previously…

High Energy Astrophysical Phenomena · Physics 2021-12-17 Louis du Plessis , Christo Venter , Zorawar Wadiasingh , Alice K. Harding , David A. H. Buckley , Stephen B. Potter , P. J. Meintjes

AR Scorpii, the so called white dwarf pulsar, contains a rapidly rotating magnetic white dwarf (WD; Pspin = 117.0564 s) interacting with a cool, red dwarf (RD) companion in a 3.56 hour orbit. It is a strong radio source with an inverted…

Solar and Stellar Astrophysics · Physics 2025-05-13 Paul E. Barrett , Mark A. Gurwell

The reclassification of AR Scorpii (AR Sco) from a delta Scuti variable star to a white dwarf binary system has initiated an in-depth exploration of this novel system. The main aim of this work was to develop a general emission code to…

High Energy Astrophysical Phenomena · Physics 2025-05-14 Louis du Plessis

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…

AE Aquarii (AE Aqr) is a cataclysmic binary hosting one of the fastest rotating (P$_{\rm spin}$ = 33.08 s) white dwarfs known. Based on seven years of Fermi Large Area Telescope (LAT) Pass 8 data, we report on a deep search for gamma-ray…

High Energy Astrophysical Phenomena · Physics 2016-11-23 Jian Li , Diego F. Torres , Nanda Rea , Emma de Ona Wilhelmi , Alessandro Papitto , Xian Hou , Christopher W. Mauche

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

We report a study of the X-ray emission from the white dwarf/M-type star binary system AR Scorpii using archival data taken in 2016-2020. It has been known that the X-ray emission is dominated by the optically thin thermal plasma emission,…

High Energy Astrophysical Phenomena · Physics 2021-02-17 J. Takata , X. F. Wang , H. H. Wang , L. C. -C. Lin , C. -P. Hu , K. L. Li , A. K. H. Kong

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 (AR Sco) is a binary star system containing the only known white dwarf (WD) pulsar. Previously reported photometric datasets only provide coverage back to 2005, but we extend the observational baseline for AR Sco back to the…

Solar and Stellar Astrophysics · Physics 2019-09-13 Erik Peterson , Colin Littlefield , Peter Garnavich
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