J/A+A/706/A200 rho Leo photometric and spectroscopic variability (Checha+, 2026)
Photometric and spectroscopic variability of blue supergiant rho Leo.
Checha V.A., Aret A., Kolka I., Liimets T., Araya I., Christen A.,
Avila Marin G.F., Levenhagen R.S., Cidale L., Eenmaee T., Hajiyeva G.,
Kivila Ue., Mitrokhina V., Ramler H., Verro T.
<Astron. Astrophys. 706, A200 (2026)>
=2026A&A...706A.200C 2026A&A...706A.200C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Stars, supergiant ; Stars, blue ; Photometry ;
Optical
Keywords: techniques: photometric - techniques: spectroscopic - stars: massive -
stars: oscillations - stars: individual: rho Leo
Abstract:
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.
We investigate the variability patterns of the evolved B-type star rho
Leo to determine its properties, identify the underlying physical
processes, and constrain its evolutionary stage. We have 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 1.5m
telescope in Estonia.
We analysed the data using the Generalized Lomb-Scargle periodogram,
Lomb-Scargle periodogram with pre-whitening, and the Weighted Wavelet
Z-Transform. To determine the fundamental parameters of rho Leo, we
fitted synthetic line profiles computed with FastWind code to the
HARPS spectrum. We used the zpektr code to infer the stellar rotation
inclination angle.
The HeI 6678.151Å 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.
Description:
The main outcome of this study is the identification of a set of
periods using various methods of frequency analysis. The periods
obtained through different techniques are in good agreement and
complement each other. Furthermore, there is a clear similarity
between the results derived from photometry and spectroscopy.
TESS data, First normalized moment data, 2017 and 2022.
Objects:
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RA (2000) DE Designation(s)
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10 32 48.67 +09 18 23.7 rho Leo = HD 91316
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tess.dat 26 6860 TESS data (table A2)
m1-2017.dat 23 363 First normalized moment data, 2017 (table A3)
m1-2022.dat 23 1106 First normalized moment data, 2022 (table A4)
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Byte-by-byte Description of file: tess.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d BJD Barycentric Julian date
19- 26 F8.5 mag dmag Differential magnitude
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Byte-by-byte Description of file: m1-2017.dat m1-2022.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d HJD Heliocentric Julian date
19- 23 F5.2 km/s M1 The first normalized moment (centroid)
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Acknowledgements:
Vitalii Checha, vitalii.checha(at)ut.ee
(End) Patricia Vannier [CDS] 10-Dec-2025