Evolutionary constraints on physical parameters and magnetic activity in double periodic variables (DPVs).
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Date
2026
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Universidad de Concepción
Abstract
Las Variables Periódicas Dobles (DPV) constituyen una clase de sistemas binarios interactuantes, cuya variabilidad de ciclo largo sigue siendo uno de los fenómenos más intrigantes de la astrofísica estelar. Esta tesis doctoral presenta una investigación sobre la naturaleza de las DVP mediante un enfoque dual: la determinación precisa de parámetros fundamentales mediante análisis fotométrico y espectroscópico, y la reconstrucción de su historia evolutiva mediante modelado numérico avanzado. Para delimitar las propiedades físicas de estos sistemas, realizamos un estudio detallado de múltiples longitudes de onda de V1001 Cen. Mediante el empleo de los modelos de síntesis de curvas de luz de Djurašević y datos espectroscópicos del espectrómetro CHIRON, derivamos las dimensiones de los componentes estelares y las propiedades del disco de acreción circumbinario. El desenredo espectroscópico mediante la técnica Gonzalez Levato permitió una estimación precisa de las temperaturas efectivas (Td = 8, 750 ± 250K; Tg = 20, 000 ± 2, 000K) y las semiamplitudes de la velocidad radial. Nuestros resultados identifican a V1001 Cen como un sistema en su segunda fase de transferencia de masa (edad ∼ 190 Myr) con una razón de masas de q ≈ 0.15, donde la estrella ganadora se rejuvenece significativamente por la acreción de material. Para complementar este marco observacional, utilizamos el código MESA (Módulos para Experimentos en Astrofísica Estelar) para explorar las vías evolutivas y la viabilidad física de los mecanismos de dinamo magnéticos. Centrándonos en el sistema HD170582, implementamos el formalismo de Tayler-Spruit para modelar el transporte de momento angular interno y la generación del campo magnético. Mediante una minimización multiparamétrica de χ2, se reprodujo con éxito el estado actual del sistema, sugiriendo masas iniciales de Md,i = 6.0M⊙ y Mg,i = 5.0M⊙ en un régimen casi conservativo ( ˙M ≈ 9.6 × 10−7M⊙yr−1). Una contribución clave de esta investigación es el análisis de la influencia del parámetro de longitud de mezcla (αMLT) en la activación de la dinamo estelar dentro de la envoltura del donante. Mediante la construcción de diagramas de diagnóstico y la variación de αMLT de 0.5 a 4.0, demostramos una fuerte correlación entre la eficiencia convectiva y el índice de ley de potencia de la dinamo (α). Nuestros hallazgos revelan que, para mantener el índice de la dinamo dentro del rango teóricamente consistente (0.33 ≤ α ≤ 0.83) y reproducir con éxito los ciclos largos observados, la longitud de mezcla debe limitarse a αMLT ≲ 2.0. Los valores que superan este umbral resultan en velocidades convectivas no físicas que inhiben el mecanismo de la dinamo de Schleicher y Mennickent. Este trabajo proporciona un marco para comprender la interacción entre la transferencia de masa, la convección estelar y el magnetismo en la evolución de sistemas binarios de interacción de masa intermedia.
Double Periodic Variables (DPVs) constitute a class of interacting binaries whose longcycle variability remains one of the most intriguing phenomena in stellar astrophysics. This doctoral thesis presents a investigation into the nature of DPVs through a dual approach: the precise determination of fundamental parameters via photometric and spectroscopic analysis, and the reconstruction of their evolutionary history using advanced numerical modeling. To constrain the physical properties of these systems, we conducted a detailed multi-wavelength study of V1001 Cen. By employing Djurašević’s light curve synthesis models and spectroscopic data from the CHIRON spectrometer, we derived the dimensions of the stellar components and the properties of the circumbinary accretion disk. Spectroscopic disentangling via the Gonzalez & Levato technique allowed for an accurate estimation of effective temperatures (Td = 8, 750 ± 250K; Tg = 20, 000 ± 2, 000K) and semi-amplitudes of radial velocity. Our results identify V1001 Cen as a system in its second phase of mass transfer (age ∼ 190 Myr) with a mass ratio of q ≈ 0.15, where the gainer star is significantly rejuvenated by the accretion of material. Complementing this observational framework, we utilized the MESA (Modules for Experiments in Stellar Astrophysics) code to explore the evolutionary pathways and the physical viability of magnetic dynamo mechanisms. Focusing on the system HD170582, we implemented the Tayler-Spruit formalism to model internal angular momentum transport and magnetic field generation. Through a multiparametric χ2 minimization, the system’s current state was successfully reproduced, suggesting initial masses of Md,i = 6.0M⊙ and Mg,i = 5.0M⊙ in a nearly conservative regime ( ˙M ≈ 9.6 × 10−7M⊙yr−1). A key contribution of this research is the analysis of the influence of the mixing length parameter (αMLT) on the activation of the stellar dynamo within the donor’s envelope. By constructing diagnostic diagrams and varying αMLT from 0.5 to 4.0, we demonstrate a strong correlation between convective efficiency and the dynamo power-law index (α). Our findings reveal that to maintain the dynamo index within the theoretically consistent range (0.33 ≤ α ≤ 0.83) and successfully reproduce the observed long cycles, the mixing length must be constrained to αMLT ≲ 2.0. Values exceeding this threshold result in unphysical convective velocities that inhibit the Schleicher & Mennickent dynamo mechanism. This work provides a framework for understanding the interplay between mass transfer, stellar convection, and magnetism in the evolution of intermediate-mass interacting binaries.
Double Periodic Variables (DPVs) constitute a class of interacting binaries whose longcycle variability remains one of the most intriguing phenomena in stellar astrophysics. This doctoral thesis presents a investigation into the nature of DPVs through a dual approach: the precise determination of fundamental parameters via photometric and spectroscopic analysis, and the reconstruction of their evolutionary history using advanced numerical modeling. To constrain the physical properties of these systems, we conducted a detailed multi-wavelength study of V1001 Cen. By employing Djurašević’s light curve synthesis models and spectroscopic data from the CHIRON spectrometer, we derived the dimensions of the stellar components and the properties of the circumbinary accretion disk. Spectroscopic disentangling via the Gonzalez & Levato technique allowed for an accurate estimation of effective temperatures (Td = 8, 750 ± 250K; Tg = 20, 000 ± 2, 000K) and semi-amplitudes of radial velocity. Our results identify V1001 Cen as a system in its second phase of mass transfer (age ∼ 190 Myr) with a mass ratio of q ≈ 0.15, where the gainer star is significantly rejuvenated by the accretion of material. Complementing this observational framework, we utilized the MESA (Modules for Experiments in Stellar Astrophysics) code to explore the evolutionary pathways and the physical viability of magnetic dynamo mechanisms. Focusing on the system HD170582, we implemented the Tayler-Spruit formalism to model internal angular momentum transport and magnetic field generation. Through a multiparametric χ2 minimization, the system’s current state was successfully reproduced, suggesting initial masses of Md,i = 6.0M⊙ and Mg,i = 5.0M⊙ in a nearly conservative regime ( ˙M ≈ 9.6 × 10−7M⊙yr−1). A key contribution of this research is the analysis of the influence of the mixing length parameter (αMLT) on the activation of the stellar dynamo within the donor’s envelope. By constructing diagnostic diagrams and varying αMLT from 0.5 to 4.0, we demonstrate a strong correlation between convective efficiency and the dynamo power-law index (α). Our findings reveal that to maintain the dynamo index within the theoretically consistent range (0.33 ≤ α ≤ 0.83) and successfully reproduce the observed long cycles, the mixing length must be constrained to αMLT ≲ 2.0. Values exceeding this threshold result in unphysical convective velocities that inhibit the Schleicher & Mennickent dynamo mechanism. This work provides a framework for understanding the interplay between mass transfer, stellar convection, and magnetism in the evolution of intermediate-mass interacting binaries.
Description
Tesis presentada para optar al grado de Doctor/a en Ciencias con mención en Física.
Keywords
Binary stars, Astrophysics