Unveiling the Variability and Chemical Composition of AL Col

In this study, we present analysis of TESS photometry, spectral energy distribution (SED), high-resolution spectroscopy, and spot modeling of the α2 CVn-type star AL Col (HD 46462). The primary objective is to determine its fundamental physical parameters and investigate its surface activity characteristics. Using TESS short-cadence (120 s) SAP flux, we identified a rotational frequency of 0.09655 d−1 (Prot=10.35733 d). Wavelet analysis reveals that while the amplitudes of the harmonic components vary over time, the strength of the primary rotational frequency remains stable. A SED analysis of multi-band photometric data yields an effective temperature (Teff) of 11,750 K. High-resolution spectroscopic observations covering wavelengthrange 4500–7000 Å provide refined estimates of Teff = 13,814 ± 400 K, logg = 4.09 ± 0.08 dex, and υsini = 16 ± 1 km s−1. Abundance analysis shows solar-like composition of O ii, Mg ii, S ii, and Ca ii, while helium is under-abundant by 0.62 dex. Rare earth elements (REEs) exhibit over-abundances of up to 5.2 dex, classifying the star as an Ap/Bp-type star. AL Col has a radius of R=3.74±0.48R⊙, with its H–R diagram position estimating a mass of M=4.2±0.2M⊙ and an age of 0.12±0.01 Gyr, indicating that the star has slightly evolved from the main sequence. The TESS light curves were modeled using a three-evolving-spot configuration, suggesting the presence of differential rotation. This star is a promising candidate for future investigations of magnetic field diagnostics and the vertical stratification of chemical elements in its atmosphere.

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Publication Details

Journal
Galaxies
Published
2025-08-14
DOI
https://doi.org/10.3390/galaxies13040093
Primary Topic
Pacific and Southeast Asian Studies
Type
article
Field-Weighted Citation Impact
0.00

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article

Unveiling the Variability and Chemical Composition of AL Col

Surath C. Ghosh, J. A. Rosales, Kefeng Tan, Otto Trust et al.
Galaxies
Pacific and Southeast Asian Studies
article

Unveiling the Variability and Chemical Composition of AL Col

Surath C. Ghosh, J. A. Rosales, Kefeng Tan, Otto Trust, O. Yu. Malkov, Harinder P. Singh, Athul Dileep, S. S. Bedi, Mrinmoy Sarkar, Santosh Joshi, Nicolás Esteban Castro-Toledo
article en

Abstract

In this study, we present analysis of TESS photometry, spectral energy distribution (SED), high-resolution spectroscopy, and spot modeling of the α2 CVn-type star AL Col (HD 46462). The primary objective is to determine its fundamental physical parameters and investigate its surface activity characteristics. Using TESS short-cadence (120 s) SAP flux, we identified a rotational frequency of 0.09655 d−1 (Prot=10.35733 d). Wavelet analysis reveals that while the amplitudes of the harmonic components vary over time, the strength of the primary rotational frequency remains stable. A SED analysis of multi-band photometric data yields an effective temperature (Teff) of 11,750 K. High-resolution spectroscopic observations covering wavelengthrange 4500–7000 Å provide refined estimates of Teff = 13,814 ± 400 K, logg = 4.09 ± 0.08 dex, and υsini = 16 ± 1 km s−1. Abundance analysis shows solar-like composition of O ii, Mg ii, S ii, and Ca ii, while helium is under-abundant by 0.62 dex. Rare earth elements (REEs) exhibit over-abundances of up to 5.2 dex, classifying the star as an Ap/Bp-type star. AL Col has a radius of R=3.74±0.48R⊙, with its H–R diagram position estimating a mass of M=4.2±0.2M⊙ and an age of 0.12±0.01 Gyr, indicating that the star has slightly evolved from the main sequence. The TESS light curves were modeled using a three-evolving-spot configuration, suggesting the presence of differential rotation. This star is a promising candidate for future investigations of magnetic field diagnostics and the vertical stratification of chemical elements in its atmosphere.

GalaxiesVol. 13(4)
University of Delhi (IN), M.J.P. Rohilkhand University (IN), Mbarara University of Science and Technology (UG), University of Concepción (CL), Chinese Academy of Sciences (CN), Aryabhatta Research Institute of Observational Sciences (IN), Institute of Applied Astronomy (RU), National Astronomical Observatories (CN), Kyambogo University (UG)
National Aeronautics and Space Administration, National Natural Science Foundation of China, European Southern Observatory
Openalex Percentile: Top 73%
Pacific and Southeast Asian Studies
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