A decade of radial-velocity monitoring of rho Leo: moment analysis and periodic variability
Abstract
We investigate the origin of long-term spectroscopic and photometric variability in the blue supergiant rho Leo, with particular emphasis on distinguishing between intrinsic pulsations and variability induced by a possible companion. Our analysis is based on an 11.5-year spectroscopic time series obtained at Tartu Observatory, complemented by high-cadence, high-resolution spectroscopy from the Hertzsprung SONG telescope and space-based photometry from TESS. We studied line-profile variability using normalised moments of the HeI 6678, HeI 5875, and SiIII 4552 lines. Periodic signals were identified using the generalised Lomb-Scargle periodogram with iterative pre-whitening, and their temporal stability was examined with the weighted wavelet Z-transform. We detect a persistent periodic signal at P = 16.46 d in the first and third moments, present throughout the full observing interval, with a radial-velocity amplitude of 3.9 km/s. This signal is also present in the SONG data and is visible in multiple spectral lines, indicating a global origin. Photometric observations reveal a dominant variability timescale near 33 d, approximately twice the spectroscopic period. The stable 16.46-day period, present throughout the entire observing interval, most likely results from non-radial pulsations of the supergiant. A binary origin of the signal is not excluded, but distinguishing between these scenarios is complicated by the supergiant's complex variability pattern.
Related
- Companions of hot Jupiters: Two decades of radial velocity monitoring with CORALIE
- The GAPS programme at TNG. LXXIX. New mass constraints for the infant planets in the V1298,Tau system through a long-term radial-velocity monitoring with HARPS-N
- Companions of Hot Jupiters: two decades of radial velocity monitoring with CORALIE
- The GAPS programme at TNG LXXIX. New mass constraints for the infant planets in the V1298 Tau system through a long-term radial velocity monitoring with HARPS-N
- VELOcities of CEpheids (VELOCE) III. Reconstructing radial velocity curves of classical Cepheids
BibTeX
@misc{checha2026decade,
title = {{A decade of radial-velocity monitoring of rho Leo: moment analysis and periodic variability}},
author = {V. A. Checha and A. Aret and I. Kolka and T. Liimets and V. Mitrokhina and A. Kasikov and T. Eenmäe and S. P. D. Borthakur and H. Ramler},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.28039},
eprint = {2608.28039},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.28039},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A decade of radial-velocity monitoring of rho Leo: moment analysis and periodic variability
AU - V. A. Checha
AU - A. Aret
AU - I. Kolka
AU - T. Liimets
AU - V. Mitrokhina
AU - A. Kasikov
AU - T. Eenmäe
AU - S. P. D. Borthakur
AU - H. Ramler
PY - 2026
DA - 2026/08/28
PB - arXiv
DO - 10.48550/arxiv.2608.28039
UR - https://arxiv.org/abs/2608.28039
AB - We investigate the origin of long-term spectroscopic and photometric variability in the blue supergiant rho Leo, with particular emphasis on distinguishing between intrinsic pulsations and variability induced by a possible companion. Our analysis is based on an 11.5-year spectroscopic time series obtained at Tartu Observatory, complemented by high-cadence, high-resolution spectroscopy from the Hertzsprung SONG telescope and space-based photometry from TESS. We studied line-profile variability using normalised moments of the HeI 6678, HeI 5875, and SiIII 4552 lines. Periodic signals were identified using the generalised Lomb-Scargle periodogram with iterative pre-whitening, and their temporal stability was examined with the weighted wavelet Z-transform. We detect a persistent periodic signal at P = 16.46 d in the first and third moments, present throughout the full observing interval, with a radial-velocity amplitude of 3.9 km/s. This signal is also present in the SONG data and is visible in multiple spectral lines, indicating a global origin. Photometric observations reveal a dominant variability timescale near 33 d, approximately twice the spectroscopic period. The stable 16.46-day period, present throughout the entire observing interval, most likely results from non-radial pulsations of the supergiant. A binary origin of the signal is not excluded, but distinguishing between these scenarios is complicated by the supergiant's complex variability pattern.
ER -