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We report the detection of a large-scale magnetic field at the surface of the slowly-rotating fully-convective M dwarf Proxima Centauri. Ten circular polarization spectra, collected from April to July 2017 with the HARPS-Pol…

We investigate the evolution of magnetic fields generated by the crystallization-driven dynamo in carbon-oxygen white dwarfs (WDs) with masses $\lesssim1.05\ M_{\odot}$. We use scalings for the dynamo to demonstrate that the initial…

Solar and Stellar Astrophysics · Physics 2024-10-31 Matias Castro-Tapia , Shu Zhang , Andrew Cumming

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…

Astrophysics · Physics 2008-09-09 N. R. Ikhsanov , N. G. Beskrovnaya

Catalysis of nucleon decay in white dwarfs is used to constrain the abundance of magnetic monopoles arising from Grand Unified Theories. Recent discoveries of the dimmest white dwarf ever observed, WD 1136-286 with $L = 10^{-4.94}…

Astrophysics · Physics 2008-11-26 Katherine Freese , Eleonora Krasteva

Under the assumption of a specific nonminimal coupling of torsion to Under the assumption of a specific nonminimal coupling of torsion to electromagnetism, spacetime is birefringent in the presence of a gravitational field leading to…

Astrophysics · Physics 2007-05-23 Oliver Preuss , Stefan Jordan , Mark P. Haugan , Sami K. Solanki

We present the first radiation magnetohydrodynamics simulations of the atmosphere of white dwarf stars. We demonstrate that convective energy transfer is seriously impeded by magnetic fields when the plasma-beta parameter, the thermal to…

Solar and Stellar Astrophysics · Physics 2015-10-14 P. -E. Tremblay , G. Fontaine , B. Freytag , O. Steiner , H. -G. Ludwig , M. Steffen , S. Wedemeyer , P. Brassard

We present the first measurement of the surface magnetic field of a late-M dwarf, LSR J1835+3259, with the help of the full-Stokes spectropolarimetry in the bands of diatomic molecules. Our magnetic field measurements at different…

Solar and Stellar Astrophysics · Physics 2017-10-04 Oleksii Kuzmychov , Svetlana V. Berdyugina , David M. Harrington

We wish to clarify whether strong magnetic fields can be effectively generated in typically low-mass dwarf galaxies and to assess the role of dwarf galaxies in the magnetization of the Universe. We performed a search for radio emission and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Krzysztof T. Chyzy , Marek Wezgowiec , Rainer Beck , Dominik J. Bomans

PG 2131+066 is a composite-spectrum binary with a hot pulsating PG 1159-type pre-white dwarf and an early M-type main sequence star. Analysis of Whole Earth Telescope observations of the pulsating pre-white dwarf component provided an…

Astrophysics · Physics 2009-10-31 M. Reed , Steven D. Kawaler , M. Sean O'Brien

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…

Solar and Stellar Astrophysics · Physics 2015-08-19 Yevgeni Kissin , Christopher Thompson

AU Mic is a young, very active M dwarf star with a debris disk and at least one transiting Neptune-size planet. Here we present detailed analysis of the magnetic field of AU Mic based on previously unpublished high-resolution optical and…

Solar and Stellar Astrophysics · Physics 2020-10-21 Oleg Kochukhov , Ansgar Reiners

The discovery of pulsations in ultra-massive white dwarfs can help to probe their interiors and unveil their core composition and crystallized mass fraction through asteroseismic techniques. To date, the richest pulsating ultra-massive…

We present the discovery of only the third brown dwarf known to eclipse a non-accreting white dwarf. Gaia parallax information and multi-colour photometry confirm that the white dwarf is cool (9950$\pm$150K) and has a low mass…

A magnetic dynamo driven by differential rotation generated when stars merge can explain strong fields in certain classes of magnetic stars, including the high field magnetic white dwarfs (HFMWDs). In their case the site of the differential…

Solar and Stellar Astrophysics · Physics 2015-06-23 Gordon P. Briggs , Lilia Ferrario , Christopher A. Tout , Dayal T. Wickramasinghe , Jarrod R. Hurley

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…

Astrophysics · Physics 2009-10-31 J. L. Sokoloski , Lars Bildsten

We present a spectroscopic survey of 248 white dwarf candidates within 40 pc of the Sun; of these 244 are in the southern hemisphere. Observations were performed mostly with the Very Large Telescope (X-Shooter) and Southern Astrophysical…

Close M-dwarf binaries and higher multiples allow the investigation of rotational evolution and mean magnetic flux unbiased from scatter in inclination angle and age since the orientation of the spin axis of the components is most likely…

Solar and Stellar Astrophysics · Physics 2015-05-30 D. Shulyak , A. Seifahrt , A. Reiners , O. Kochukhov , N. Piskunov

We study the strongly magnetized white dwarf configurations in a self-consistent manner as a progenitor of the over-luminous type-Ia supernovae. We compute static equilibria of white dwarf stars containing a strong magnetic field and…

Solar and Stellar Astrophysics · Physics 2017-10-25 Prasanta Bera , Dipankar Bhattacharya

We have presented 309 new white-dwarf (WD) + main-sequence (MS) star binaries identified from the Sloan Digital Sky Survey (SDSS) Tenth Data Release (DR10). The majority of them consist of a white dwarf and a low-mass secondary (typically M…

Solar and Stellar Astrophysics · Physics 2015-06-23 Lifang Li , Xiaobo Gong , Fenghui Zhang , Quanwang Han , Xiaoyang Kong

We identify SDSS J130033.48+590407.0 as a common proper motion companion to the well-studied DA white dwarf PG 1258+593 (GD322). The system lies at a distance of 68 +/- 3 pc, where the angular separation of 16.1 +/- 0.1 arcsec corresponds…

Solar and Stellar Astrophysics · Physics 2015-05-14 J. Girven , B. T. Gänsicke , B. Külebi , D. Steeghs , S. Jordan , T. R. Marsh , D. Koester