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.
Authors
- Surath C. Ghosh
- J. A. Rosales (ORCID: https://orcid.org/0000-0001-6657-9121)
- Kefeng Tan (ORCID: https://orcid.org/0000-0003-0173-6397)
- Otto Trust (ORCID: https://orcid.org/0000-0001-5209-7041)
- O. Yu. Malkov (ORCID: https://orcid.org/0000-0002-1558-4198)
- Harinder P. Singh (ORCID: https://orcid.org/0000-0001-6802-6539)
- Athul Dileep (ORCID: https://orcid.org/0000-0002-2011-6233)
- S. S. Bedi (ORCID: https://orcid.org/0000-0003-3377-3272)
- Mrinmoy Sarkar (ORCID: https://orcid.org/0009-0004-4861-6012)
- Santosh Joshi
- Nicolás Esteban Castro-Toledo
Institutions
- 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)
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
Funders
- National Aeronautics and Space Administration
- National Natural Science Foundation of China
- European Southern Observatory