Strongly Magnetized White Dwarfs and Their Instability Due to Nuclear Processes

Author(s)

Otoniel, E. ^[1] ; Franzon, B. ^[2] ; Carvalho, G. A. ^{[3, 4, 5, 6]} ; Malheiro, M. ^[3] ; Schramm, S. ^[2] ; Weber, F. ^{[7, 8]}

Affiliation

^[1] Univ Fed Cariri Brejo Santo, Inst Form Educadores, BR-63260000 Brejo Santo, CE - Brazil

^[2] Frankfurt Inst Adv Studies, Ruth Moufang 1, D-60438 Frankfurt - Germany

^[3] Inst Tecnol Aeronaut, Dept Fis, BR-12228900 Sao Jose Dos Campos, SP - Brazil

^[4] Sapienza Univ Roma, Dipartimento Fis, Ple Aldo Moro 5, I-00185 Rome - Italy

^[5] Sapienza Univ Roma, ICRA, Ple Aldo Moro 5, I-00185 Rome - Italy

^[6] ICRANet, Pzza Repubbl 10, I-65122 Pescara - Italy

^[7] Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 - USA

^[8] San Diego State Univ, Dept Phys, 5500 Campanile Dr, San Diego, CA 92182 - USA

• Document type: Journal article
• Source: ASTROPHYSICAL JOURNAL; v. 879, n. 1 JUL 1 2019.
• Web of Science Citations: 1

Abstract

In this work, we study the properties of strongly magnetized white dwarfs (WDs), taking into account the electron capture and pycnonuclear fusion reactions instabilities. The structure of WDs is obtained by solving the Einstein-Maxwell equations with a poloidal magnetic field in a fully general relativistic treatment. The stellar fluid is assumed to be composed of a regular crystal lattice made of carbon ions immersed in a degenerate relativistic electron gas. The onset of electron capture reactions and pycnonuclear reactions are determined with and without magnetic fields. We find that magnetized WDs significantly exceed the standard Chandrasekhar mass limit, even when electron capture and pycnonuclear fusion reactions are present in the stellar interior. We obtain a maximum white dwarf mass of around 2.14 M-circle dot for a central magnetic field of similar to 3.85 x 10(14)G, which indicates that magnetized WDs may play a crucial role for the interpretation of superluminous type Ia supernovae. Furthermore, we show that the critical density for pycnonuclear fusion reactions limits the central white dwarf density to 9.35 x 10(9)g cm(-3). As a consequence, equatorial radii of WDs cannot be smaller than similar to 1100 km. Another interesting feature concerns the relationship between the central stellar density and the strength of the magnetic field at the core of a magnetized white dwarf. For high magnetic fields, we find that the central density increases (stellar radius decrease) with magnetic field strength, which makes highly magnetized WDs more compact. The situation is reversed if the central magnetic field is less than similar to 10(13)G. (AU)

• FAPESP's process: 13/26258-4 - Superdense matter in the universe
• Grantee: Manuel Máximo Bastos Malheiro de Oliveira
• Support Opportunities: Research Projects - Thematic Grants