Clues on the Origin and Evolution of Massive Contact Binaries: Atmosphere Analysis of VFTS 352

Autor(es):Mostrar menos -

Abdul-Masih, Michael ^[1] ; Sana, Hugues ^[1] ; Sundqvist, Jon ^[1] ; Mahy, Laurent ^[1] ; Menon, Athira ^[2] ; Almeida, Leonardo A. ^[3] ; De Koter, Alex ^{[2, 1]} ; de Mink, Selma E. ^[2] ; Justham, Stephen ^{[2, 4]} ; Langer, Norbert ^[5] ; Puls, Joachim ^[6] ; Shenar, Tomer ^[1] ; Tramper, Frank ^[7]

Afiliação do(s) autor(es)

^[1] KULeuven, Inst Astrophys, Celestijnenlaan 200 D, B-3001 Leuven - Belgium

^[2] Univ Amsterdam, Astron Inst Anton Pannekoek, Sci Pk 904, NL-1098 XH Amsterdam - Netherlands

^[3] Univ Fed Rio Grande do Norte, Dept Fis Teor & Expt, CP 1641, BR-59072970 Natal, RN - Brazil

^[4] Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100012 - Peoples R China

^[5] Univ Bonn, Argelander Inst Astron, Hugel 71, D-53121 Bonn - Germany

^[6] LMU Munchen, Univ Sternwarte, Scheinerstr 1, D-81679 Munich - Germany

^[7] Natl Observ Athens, Inst Astron Astrophys Space Applicat & Remote Sen, Athens 15236 - Greece

• Tipo de documento: Artigo Científico
• Fonte: ASTROPHYSICAL JOURNAL; v. 880, n. 2 AUG 1 2019.
• Citações Web of Science: 0

Resumo

The massive O4.5 V + O5.5 V binary VFTS 352 in the Tarantula Nebula is one of the shortest-period and most massive overcontact binaries known. Recent theoretical studies indicate that some of these systems could ultimately lead to the formation of gravitational waves via black hole binary mergers through the chemically homogeneous evolution pathway. By analyzing ultraviolet-optical phase-resolved spectroscopic data, we aim to constrain atmospheric and wind properties that could be later used to confront theoretical predictions from binary evolution. In particular, surface abundances are powerful diagnostics of the evolutionary status, mass transfer, and internal mixing processes. From a set of 32 Very Large Telescope/FLAMES visual and eight Hubble Space Telescope/Cosmic Origins Spectrograph ultraviolet spectra, we used spectral disentangling to separate the primary and secondary components. Using a genetic algorithm wrapped around the NLTE model atmosphere and the spectral synthesis code FASTWIND, we perform an 11-parameter optimization to derive the atmospheric and wind parameters of both components, including the surface abundances of He, C, N, O, and Si. We find that both components are hotter than expected compared to single-star evolutionary models, indicating that additional mixing processes may be at play. However, the derived chemical abundances do not show significant indications of mixing when adopting baseline values typical of the system environment. (AU)

• Processo FAPESP: 12/09716-6 - Distâncias precisas de aglomerados jovens através de binárias eclipsantes massivas
• Beneficiário: Leonardo Andrade de Almeida
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 11/51680-6 - Explorando o universo: da formação de galáxias aos planetas tipo-terra, com o Telescópio Gigante Magellan
• Beneficiário: João Evangelista Steiner
• Linha de fomento: Auxílio à Pesquisa - Projetos Especiais
• Processo FAPESP: 13/18245-0 - Soluções orbitais espectroscópicas completas para mais de 100 binárias massivas na região do "starburst" 30 Dourados
• Beneficiário: Leonardo Andrade de Almeida
• Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado