Absolute parameters of young stars: V puppis

ABSTRACT New spectrometric data on V Pup are combined with satellite photometry [HIPPARCOS and recent Transiting Exoplanet Survey Satellite (TESS)] to allow a revision of the absolute parameters with increased precision. We find: M1 = 14.0 ± 0.5, M2 = 7.3 ± 0.3 (M⊙); R1 = 5.48 ± 0.18, R2 = 4.59 ± 0.15 (R⊙); T1 26 000 ± 1000, T2 24 000 ± 1000 (K), age 5 ± 1 (Myr), photometric distance 320 ± 10 (pc). The TESS photometry reveals low-amplitude (∼0.002 mag) variations of the β Cep kind, consistent with the deduced evolutionary condition and age of the optical primary. This fact provides independent support to our understanding of the system as in a process of Case A type interactive evolution that can be compared with μ1 Sco. The ∼10 M⊙ amount of matter shed by the overluminous present secondary must have been mostly ejected from the system rather than transferred, thus taking angular momentum out of the orbit and keeping the pair in relative close proximity. New times of minima for V Pup have been studied and the results compared with previous analyses. The implied variation of period is consistent with the Case A evolutionary model, though we offer only a tentative sketch of the original arrangement of this massive system. We are not able to confirm the previously reported cyclical variations having a 5.47-yr period with the new data, though a direct comparison between the HIPPARCOS and TESS photometry points to the presence of third light from a star that is cooler than those of the close binary, as mentioned in previous literature.