相关论文: AR Sco: A White Dwarf Synchronar

We report the first result from our survey of rapid variability in symbiotic binaries: the discovery of a persistent oscillation at P=1682.6 +- 0.6 s in the optical emission from the prototype symbiotic, Z Andromedae. The oscillation was…

It has long been accepted that a possible mechanism for explaining the existence of magnetic white dwarfs is the merger of a binary white dwarf system, as there are viable mechanisms for producing sustainable magnetism within the merger…

We have identified 109 White Dwarf (WD) - M dwarf pairs in the Sloan Digital Sky Survey (SDSS) with g < 20th magnitude. For each system we determined the temperature of the WD primary and the spectral type of the M dwarf secondary. Using…

M dwarfs remain active over longer timescales than their Sunlike counterparts, with potentially devastating implications for the atmospheres of their planets. However, the age at which fully-convective M dwarfs transition from active and…

The observed properties of the close binary AE Aqr indicate that the mass transfer in this system operates via the Roche lobe overflow mechanism, but the material transferred from the normal companion is neither accreted onto the surface of…

White dwarfs with surface magnetic fields in excess of $1 $MG are found as isolated single stars and relatively more often in magnetic cataclysmic variables. Some 1,253 white dwarfs with a detached low-mass main-sequence companion are…

The merger of two white dwarfs is expected to result in a central fast rotating core surrounded by a debris disk, in which magnetorotational instabilities give rise to a hot magnetized corona and a magnetized outflow. The dissipation of…

Although the internal structure of white dwarfs is considered to be generally well understood, the source and entity of viscosity is still very uncertain. We propose here to study white dwarf viscous properties using short period (< 1 hr),…

We analyse the K2 short cadence data of the intermediate polar FO Aqr and provide accurate and updated orbital and spin periodicities. We additionally find small spin period changes as a function of orbital phase of ~0.02 seconds…

Spider pulsars are compact binary systems composed of a millisecond pulsar and a low-mass companion. Their X-ray emission - modulated on the orbital period - is interpreted as synchrotron radiation from high-energy electrons accelerated at…

The nature of the excess near-infrared emission associated with the magnetic white dwarf commonly known as SDSS 1212 is investigated primarily through spectroscopy, and also via photometry. The inferred low mass secondary in this system has…

Simulation of Doppler H-alpha tomogram of the nova-like star AE Aquarii suggests that the dipole magnetic moment of the white dwarf is close to 1.5E+34 G cm^3. This is consistent with the lower limit to the magnetic field strength of the…

The magnetic white dwarf SDSS J121209.31+013627.7 exhibits a weak, narrow Halpha emission line whose radial velocity and strength are modulated on a period of ~90 minutes. Though indicative of irradiation on a nearby companion, no cool…

Magnetic fields can play an important role in stellar evolution. Among white dwarfs, the most common stellar remnant, the fraction of magnetic systems is more than 20 per cent. The origin of magnetic fields in white dwarfs, which show…

The origin of highly-magnetized white dwarfs has remained a mystery since their initial discovery. Recent observations indicate that the formation of high-field magnetic white dwarfs is intimately related to strong binary interactions…

Accretion of mass onto a white dwarf (WD) in a binary system can lead to stellar explosions. If a WD accretes from stellar wind of a distant evolved giant in a symbiotic binary, it can undergo occasional outbursts in which it brightens by…

Asynchronous polars (APs) are accreting white dwarfs (WDs) that have different WD and orbital angular velocities, unlike the rest of the known polars, which rotate synchronously (i.e., their WD and orbital angular velocities are the same).…

The magnetism and rotation of white dwarf (WD) stars are investigated in relation to a hydromagnetic dynamo operating in the progenitor during shell burning phases. The downward pumping of angular momentum in the convective envelope, in…

AR Scorpii is a close binary system containing a rotation powered white dwarf and a low mass M type companion star. This system shows non-thermal emission extending up to the X-ray energy range. We consider hybrid (lepto-hadronic) and pure…

A dynamo mechanism driven by differential rotation when stars merge has been proposed to explain the presence of strong fields in certain classes of magnetic stars. In the case of the high field magnetic white dwarfs (HFMWDs), the site of…