Photometric and spectroscopic variability of the blue supergiant ρ Leo
Year: 2026
Type: article
Abstract: Context. The post-main-sequence evolution of massive stars remains poorly understood, particularly in the case of blue supergiants. As key drivers of the dynamical and chemical evolution of galaxies, massive stars warrant detailed investigation during this complex evolutionary stage. Hot supergiants exhibit pronounced photometric and spectroscopic variability, typically in the form of quasi-periodic rather than strictly periodic variations. Aims. We investigated the variability patterns of the evolved B-type star ρ Leo to determine its properties, identify the underlying physical processes, and constrain its evolutionary stage. We combined extensive long-term datasets of spectroscopic and photometric observations from various sources. These include data from the TESS and Kepler space telescopes, as well as observations from the 1.5 m telescope in Estonia. Methods. We analysed the data using the generalized Lomb–Scargle periodogram, the Lomb–Scargle periodogram with pre-whitening, and the weighted wavelet Z-transform. To determine the fundamental parameters of ρ Leo, we fitted synthetic line profiles computed with the F AST W IND code to the HARPS spectrum. We used the ZPEKTR code to infer the stellar rotation inclination angle. Results. The He I 6678.151 Å line profile exhibits significant changes in radial velocity and, consequently, in its moment values. We identify a set of periods and harmonics ranging from ∼0.8 to ∼35 days. Some periods remain nearly constant, while others appear and disappear from one observing season to another. A comparison of spectroscopic and photometric data, along with the shape of the phase curves, helps to constrain the nature of several periods. In particular, the ∼11-day period is attributed to stellar rotation, while the ∼17-day period is associated with radial pulsations. Conclusions. Despite their quasi-periodic nature, most periods are observable across multiple observing seasons. Based on the fairly wide range of detected periods, ρ Leo is likely on the blue loop of its evolution, following the red supergiant stage.
Source: Astronomy and Astrophysics
Authors: V. A. Checha, A. Aret, I. Kolka, T. Liimets, I. Araya, A. Christen, G. F. Avila Marín, R. S. Levenhagen, L. Cidale, T. Eenmäe, G. Hajiyeva, Ü. Kivila, V. Mitrokhina, H. Ramler, T. Verro
Institutions: Tartu Observatory, University of Tartu, Universidad Mayor, Valparaiso University, University of Valparaíso, Universidade Federal de São Paulo, Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Astrofísica de La Plata, Universidad Nacional de La Plata, Khazar University, Shamakhy Astrophysical Observatory named after Nasraddin Tusi
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Awards: G2432649393, G2714512662, Physics of Extreme Massive Stars, G4755043463, Physics of Extreme Massive Stars, Overcoming challenges in the evolution and nature of massive stars, Building Excellence in Spectral Characterisation of Exoplanet Hosts and Other Stars, G6586618239, G6622439793, G701014588, G8278124175, Radiative and dynamical modeling of engine-powered superluminous supernovae
OpenAlex ID: W4417530764