V1001 Cen: A dual approach of spectroscopy and numerical modeling to understand stellar evolution and dynamo mechanisms

¹ Departamento de Astronomía, Universidad de Concepción, Casilla 160-C, Concepción, Chile
² Dipartimento di Fisica, Sapienza, Universita di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy
³ Astronomical Observatory, Volgina 7, 11060 Belgrade 38, Serbia
⁴ Isaac Newton Institute of Chile, Yugoslavia Branch, 11060 Belgrade, Serbia

^⋆ Corresponding author: paulcalderon@udec.cl

Received: 31 January 2025
Accepted: 14 August 2025

Abstract

This study aims to determine the fundamental parameters of the binary system V1001 Cen, which remain poorly constrained. We conducted a photometric and spectroscopic study in the visual band of V1001 Cen, a system comprising two stellar components. Using Djurašević’s models, we derived the physical parameters of both stars, the accretion disk around the gainer star, and the system’s overall dimensions. Spectroscopic data from the CHIRON spectrometer allowed us to estimate the effective temperatures, semi amplitudes of radial velocity, and component masses. Disentangling the spectra using the Gonzalez & Levato (2006, A&A, 448, 283) technique provided additional details about the stellar components. Evolutionary models were generated using the MESA code, and comparisons with Van Rensbergen’s models were used to assess the system’s evolutionary stage. The orbital period of V1001 Cen was determined to be 6.73 ± 0.01 days, with a long period of 247.28 ± 10.0 days. The color excess was estimated as E(B − V) = 0.6351 ± 0.0292 mag. Semi amplitudes of radial velocity were measured at 21.70 ± 0.38 km s⁻¹ and 142.33 ± 0.34 km s⁻¹. The effective temperatures, determined using the spectrum code, are 8 750 ± 250 K for the donor star and 20 000 ± 2000 K for the gainer star. Masses were found to be 0.85 ± 0.1 M_⊙ and 4.25 ± 0.1 M_⊙ for the donor and gainer, respectively. The system, with an estimated age of 190 million years, is in its second phase of mass transfer, nearly conservative, with Ṁ = 1.13 × 10⁻⁷ M_⊙ yr⁻¹. Mass transfer began 58 million years ago. The best fitting light curve model indicates an inclination angle of i = 68.​​° 3 ± 0.​​° 3, R_g = 2.68 ± 0.1 R_⊙, R_d = 6.47 ± 0.1 R_⊙, T_g = 18 310 ± 500 K, and T_d = 8750 ± 250 K, parameters belonging to the gainer and donor, respectively.