Multisite spectroscopic seismic study of the β Cep star V2052 Ophiuchi: Inhibition of mixing by its magnetic field

• Autores: Briquet, M.; Neiner, C.; Aerts, C.; Morel, T.; Mathis, S.; Reese, D. R.; Lehmann, H.; Costero, R.; Echevarria, J.; Handler, G.; Kambe, E.; Hirata, R.; Masuda, S.; Wright, D.; Yang, S.; Pintado, Olga Ines; Mkrtichian, D.; Lee, B. C.; Han, I.; Bruch, A.; De Cat, P.; Uytterhoeven, K.; Lefever, K.; Vanautgaerden, J.; de Batz, B.; Frémat, Y.; Henrichs, H.; Geers, V. C.; Martayan, C.; Hubert, A. M.; Thizy, O.; Tijani, A.
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: STARS: EARLY-TYPE; STARS: INDIVIDUAL: V2052 OPH; STARS: INTERIORS; STARS: MAGNETIC FIELD; STARSPOTS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

We used extensive ground-based multisite and archival spectroscopy to derive observational constraints for a seismic modelling of the magnetic β Cep star V2052 Ophiuchi. The line-profile variability is dominated by a radial mode (f 1 = 7.14846d -1) and by rotational modulation (P rot = 3.638833d). Two non-radial low-amplitude modes (f 2 = 7.75603d -1 and f 3 = 6.82308d -1) are also detected. The four periodicities that we found are the same as the ones discovered from a companion multisite photometric campaign and known in the literature. Using the photometric constraints on the degrees ℓ of the pulsation modes, we show that both f 2 and f 3 are prograde modes with (ℓ, m) = (4, 2) or (4, 3). These results allowed us to deduce ranges for the mass (M ∈ [8.2, 9.6]M ⊙) and central hydrogen abundance (X c ∈ [0.25, 0.32]) of V2052 Oph, to identify the radial orders n 1 = 1, n 2 = -3 and n 3 = -2, and to derive an equatorial rotation velocity v eq ∈ [71, 75]kms -1. The model parameters are in full agreement with the effective temperature and surface gravity deduced from spectroscopy. Only models with no or mild core overshooting (α ov ∈ [0, 0.15] local pressure scale heights) can account for the observed properties. Such a low overshooting is opposite to our previous modelling results for the non-magnetic β Cep star θ Oph having very similar parameters, except for a slower surface rotation rate. We discuss whether this result can be explained by the presence of a magnetic field in V2052 Oph that inhibits mixing in its interior.
Fil: Briquet, M.. Katholikie Universiteit Leuven; Bélgica. Université Paris Diderot - Paris 7; Francia. Université de Liège; Bélgica
Fil: Neiner, C.. Université Paris Diderot - Paris 7; Francia
Fil: Aerts, C.. Radboud Universiteit Nijmegen; Países Bajos. Katholikie Universiteit Leuven; Bélgica
Fil: Morel, T.. Université de Liège; Bélgica
Fil: Mathis, S.. Université Paris Diderot - Paris 7; Francia
Fil: Reese, D. R.. Université de Liège; Bélgica
Fil: Lehmann, H.. Thuringer Landessternwarte Tautenburg; Alemania
Fil: Costero, R.. Universidad Nacional Autónoma de México; México
Fil: Echevarria, J.. Universidad Nacional Autónoma de México; México
Fil: Handler, G.. Copernicus Astronomical Center; Polonia
Fil: Kambe, E.. National Astronomical Observatory of Japan; Japón
Fil: Hirata, R.. Otokoyama-Yutoku 7; Japón
Fil: Masuda, S.. Hayashi 2528-5; Japón
Fil: Wright, D.. University Of New South Wales; Australia
Fil: Yang, S.. University Of Victoria; Canadá
Fil: Pintado, Olga Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Correlación Geológica. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Departamento de Geología. Cátedra Geología Estructural. Instituto Superior de Correlación Geológica; Argentina
Fil: Mkrtichian, D.. National Astronomical Research. Institute of Thailand; Tailandia
Fil: Lee, B. C.. Korea Astronomy And Space Science Institute; Corea del Sur
Fil: Han, I.. Korea Astronomy And Space Science Institute; Corea del Sur
Fil: Bruch, A.. Mcti/laboratório Nacional de Astrofísica;
Fil: De Cat, P.. Royal Observatory Of Belgium; Bélgica
Fil: Uytterhoeven, K.. Universidad de La Laguna; España. Instituto Astrofísico de Canarias.; España
Fil: Lefever, K.. Katholikie Universiteit Leuven; Bélgica. Belgian Institute for Space Aeronomy.; Bélgica
Fil: Vanautgaerden, J.. Katholikie Universiteit Leuven; Bélgica
Fil: de Batz, B.. Université Paris Diderot - Paris 7; Francia
Fil: Frémat, Y.. Royal Observatory of Belgium-; Bélgica
Fil: Henrichs, H.. University of Amsterdam, Astronomical Institute Anton Pannekoek.; Países Bajos
Fil: Geers, V. C.. Institute for Astronomy. ETH Zurich.; Suiza
Fil: Martayan, C.. European Organization For Astronomical Research In The Southern Hemisphere; Chile
Fil: Hubert, A. M.. Université Paris Diderot - Paris 7; Francia
Fil: Thizy, O.. Shelyak Instruments; Francia
Fil: Tijani, A.. University of Amsterdam, Astronomical Institute Anton Pannekoek.; Países Bajos