Article
Physics, Multidisciplinary
S. Y. El-Monier, A. Atteya
Summary: A theoretical investigation is presented for dust-acoustic waves in a collisionless Thomas-Fermi magnetoplasma. The KdV and KdV type equations are derived using the reductive perturbation method. The solutions of these equations are obtained and the contribution of higher-order corrections to the dust-acoustic waves is investigated. The electric field and soliton energy are also derived.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Astronomy & Astrophysics
Jenni R. French, Sarah L. Casewell, Trent J. Dupuy, John H. Debes, Elena Manjavacas, Emily C. Martin, Siyi Xu
Summary: We confirm SDSS J222551.65+001637.7AB as a closely separated, resolved white dwarf-brown dwarf binary. The binary consists of a white dwarf with a temperature of 10926 +/- 246 K and a brown dwarf companion of L4 spectral type, separated by 0.9498 +/- 0.0022 arcsec. The age of the binary is estimated to be 1.97(-0.76)(+4.41) Gyr. This binary is likely a member of the thick disc and is the third closest spatially resolved white dwarf-brown dwarf binary known.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
A. Kosakowski, M. Kilic, W. R. Brown, P. Bergeron, T. Kupfer
Summary: The study presents the discovery of nine deeply eclipsing white dwarf candidates in the ZTF data, four of which were further investigated. Three systems were found to exhibit total eclipses in both ZTF and follow-up observations. It was revealed that all four systems contain a white dwarf with low-mass stellar companions. Additionally, the study identified 41 additional eclipsing WD+M candidates, including two new candidate short-period white dwarf-brown dwarf binaries.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
N. P. Gentile Fusillo, P-E Tremblay, E. Cukanovaite, A. Vorontseva, R. Lallement, M. Hollands, B. T. Gansicke, K. B. Burdge, J. McCleery, S. Jordan
Summary: In this study, a catalogue of white dwarf candidates was presented based on Gaia Early Data Release 3 (EDR3) and compared with samples from Sloan Digital Sky Survey (SDSS). The distribution of these candidates was mapped in the Gaia absolute magnitude-colour space, and a probability of being a white dwarf was calculated for over 1.3 million sources. High-confidence white dwarf candidates were selected based on these calculations and stellar parameters were estimated using synthetic atmospheric models. The catalogue was found to have an overall completeness limit of 93% for white dwarfs with G <= 20 mag and effective temperature (T-eff) > 7000 K at high Galactic latitudes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Mathematics, Applied
Lazhar Bougo, Smail Bougou, Ammar Khanfer
Summary: The existence and uniqueness of the generalized boundary value problem of the Thomas-Fermi equation is proven, where y''+f(x,y)=0, 0<infinity, y(0)=1, y(infinity)=0, p(y)f(x,y)=-yp+1, p>0, 0<x<infinity. Additionally, highly accurate approximate solutions for this new boundary value problem in the study of many-electron systems are obtained.
Article
Astronomy & Astrophysics
Mukremin Kilic, P. Bergeron, Simon Blouin, A. Bedard
Summary: This study analyzes the most massive white dwarf candidates in the Montreal White Dwarf Database, identifying a significant portion that are close to the maximum mass of CO core models and likely formed through binary mergers. Outliers in transverse velocity, magnetic properties, and rapid rotation indicate that a substantial number of ultramassive white dwarfs in the sample are likely products of mergers.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Physics, Multidisciplinary
Homa Shababi
Summary: In this paper, we present a generalized formulation of the Thomas-Fermi equations by considering the effect of a noncommutative space-time. Various variants of the model are discussed, including zero temperature, thermal effects, non-relativistic and relativistic regimes, and very strong magnetic field. The effects of noncommutativity on the Thomas-Fermi length are illustrated through the treatment of dielectric screening.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
S. G. Parsons, M. S. Hernandez, O. Toloza, M. Zorotovic, M. R. Schreiber, B. T. Gansicke, F. Lagos, R. Raddi, A. Rebassa-Mansergas, J. J. Ren, D. Koester
Summary: Virtually all binaries consisting of a white dwarf with a non-degenerate companion can be classified as close post-interaction systems or wide systems. Binaries with periods between these two extremes can provide valuable information about common envelope efficiency and alternative pathways in the creation of compact binaries. The discovery of three white dwarfs in binaries with evolved subgiant stars sheds light on the formation process of these systems and their future evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. G. Parsons, M. S. Hernandez, O. Toloza, M. Zorotovic, M. R. Schreiber, B. T. Gansicke, F. Lagos, R. Raddi, A. Rebassa-Mansergas, J. J. Ren, D. Koester
Summary: This study presents three white dwarfs in binaries with evolved subgiant stars with orbital periods of 41, 52, and 461 days. These low mass white dwarfs are likely formed from stable but non-conservative mass transfer, and one system is part of a hierarchical triple star system.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
C. Lopez-Sanjuan, P-E Tremblay, A. Ederoclite, H. Vazquez Ramio, J. M. Carrasco, J. Varela, A. J. Cenarro, A. Marin-Franch, T. Civera, S. Daflon, B. T. Gansicke, N. P. Gentile Fusillo, F. M. Jimenez-Esteban, J. Alcaniz, R. E. Angulo, D. Cristobal-Hornillos, R. A. Dupke, C. Hernandez-Monteagudo, M. Moles, L. Sodre
Summary: Using the J-PLUS optical data, we estimated the spectral evolution of white dwarfs with effective temperature. The results show that the fraction of He-dominated white dwarfs increases as the temperature decreases. Additionally, we also estimated the mass distribution of white dwarfs and found that the distribution for H-dominated white dwarfs is consistent with previous studies, while the He-dominated distribution has a single peak.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Peter McGill, Jay Anderson, Stefano Casertano, Kailash C. Sahu, Pierre Bergeron, Simon Blouin, Patrick Dufour, Leigh C. Smith, N. Wyn Evans, Vasily Belokurov, Richard L. Smart, Andrea Bellini, Annalisa Calamida, Martin Dominik, Noe Kains, Jonas Klueter, Martin Bo Nielsen, Joachim Wambsganss
Summary: In November 2019, a nearby white dwarf LAWD 37 caused an astrometric microlensing event by aligning with a distant background source. Using data from Gaia and the Hubble Space Telescope, the astrometric deflection of the background source was measured and the gravitational mass of LAWD 37 was obtained. The analysis faced challenges in extracting the lensing signal of the faint background source buried in the wings of LAWD 37's point spread function. By considering correlated noise caused by the removal of LAWD 37's point spread function, a deflection model that explains the data was found and a mass of 0.56 +/- 0.08 M? for LAWD 37 was determined, supporting current white dwarf evolutionary theory.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Felipe Lagos, Monica Zorotovic, Matthias R. Schreiber, B. T. Gansicke
Summary: The recently discovered system Gaia 0007-1605, consisting of a white dwarf with a brown dwarf companion and a distant white dwarf tertiary, resembles the triple system WD 1856+534, which is the first transiting planet candidate around a white dwarf. The formation of the inner binary in Gaia 0007-1605 could be attributed to either common envelope evolution, triple dynamics, or a combination of both mechanisms. The energy budget and Von Zeipel-Lidov-Kozai oscillations play important roles in understanding the system's current configuration.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Mathematics, Applied
Ronald E. Mickens, Isom H. Herron
Summary: In this paper, two rational approximate solutions to the Thomas-Fermi nonlinear differential equation are constructed through the principle of dynamic consistency. The differences in predicted numerical values of the two approximate solutions are examined and compared to an accurate numerical solution obtained using a fourth-order Runge-Kutta method. Additionally, several new integral relations satisfied by the bounded solutions of the TF equation are presented.
APPLIED MATHEMATICS LETTERS
(2021)
Article
Physics, Mathematical
Shu Wang, Yabo Ren
Summary: This paper investigates the existence of weak solutions to the time-dependent Thomas-Fermi equations. Approximate solutions are derived using the fractional step Lax-Friedrichs scheme, and the uniform boundedness of these approximate solutions is established. Based on the uniform energy-type estimates, it is shown that the entropy dissipation measures of the weak solution to the one-dimensional time-dependent Thomas-Fermi equations are confined in a compact set in Hloc-1. The Young measure is proven to be a Dirac measure using the Tartar-Murat commutator relation. The convergence of the approximate solutions is established using the compensated compactness method.
JOURNAL OF MATHEMATICAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
Anna Wolz, Kent Yagi, Nick Anderson, Andrew J. Taylor
Summary: The almost monochromatic gravitational waves from binary white dwarfs pose challenges in measuring their individual masses. A novel approach utilizing finite-size effects and universal relations has been developed to measure white dwarf masses with Laser Interferometer Space Antenna. Quasi-universal relations among mass, moment of inertia, and tidal deformability of white dwarfs were discovered, allowing for accurate individual mass measurements through Fisher analysis.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Education, Scientific Disciplines
Ricardo Lopez-Ruiz, Jaime Sanudo, Xavier Calbet
AMERICAN JOURNAL OF PHYSICS
(2008)
Article
Physics, Multidisciplinary
Ricardo Lopez-Ruiz, Jaime Sanudo, Xavier Calbet
Article
Physics, Applied
J. Sanudo, A. F. Pacheco
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2008)
Article
Physics, Nuclear
A. F. Pacheco, J. Sanudo
INTERNATIONAL JOURNAL OF MODERN PHYSICS E
(2008)
Article
Physics, Mathematical
R. Lopez-Ruiz, A. Nagy, E. Romera, J. Sanudo
JOURNAL OF MATHEMATICAL PHYSICS
(2009)
Article
Physics, Multidisciplinary
Jaime Sanudo, Ricardo Lopez-Ruiz
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2008)
Article
Mathematics, Applied
Ricardo Lopez-Ruiz, Jaime Sanudo
OPEN SYSTEMS & INFORMATION DYNAMICS
(2009)
Article
Mathematics, Applied
Ricardo Lopez-Ruiz, Jaime Sanudo
OPEN SYSTEMS & INFORMATION DYNAMICS
(2010)
Article
Physics, Multidisciplinary
Jaime Sanudo, Ricardo Lopez-Ruiz
Article
Physics, Multidisciplinary
Jaime Sanudo, Ricardo Lopez-Ruiz
Article
Physics, Multidisciplinary
Jaime Sanudo, Ricardo Lopez-Ruiz
Article
Physics, Multidisciplinary
Jaime Sanudo, Ricardo Lopez-Ruiz
Article
Physics, Multidisciplinary
Ricardo Lopez-Ruiz, Jaime Sanudo
Article
History & Philosophy Of Science
J. Sanudo, A. F. Pacheco
REVISTA MEXICANA DE FISICA E
(2007)
Article
Physics, Multidisciplinary
Tinggui Chen, Baizhan Xia, Dejie Yu, Chuanxing Bi
Summary: This study proposes a gradient phononic crystal structure for enhanced acoustic sensing. By breaking the symmetry of the PC structure, topologically protected edge states are introduced, resulting in topological acoustic rainbow trapping. The robustness and enhancement properties are verified numerically and experimentally.
