Space Weather & Heliophysics

Characterizing Six Seismic Solar Analogs Observed By Kepler, K2, And HERMES

By Keith Cowing

Status Report

astro-ph.SR

May 3, 2026

Filed under astro-ph.SR, EPIC~206064678, Gaia mission, heliophysics, HERMES, high-resolution spectroscopy, K2, Kepler, Mercator telescope, metallicity, Solar Analogs, Spectroscopy, Stellar Cartography

Characterizing Six Seismic Solar Analogs Observed By Kepler, K2, And HERMES — log R′_HK(T_eff) as a function of age for solar twins and solar analogs. Blue squares represent the six new seismic solar analogs listed in Table 1. Orange, dark-gray, and light-gray circles correspond to stellar samples from the literature, as indicated in the legend. The dashed line shows the empirical relation from Lorenzo-Oliveira et al. (2018). The green shaded region represents the 2σ uncertainty envelope around this relation. The Sun is represented by its red symbol. — astro-ph.SR

Solar analogs, stars that closely match the fundamental properties of the Sun, provide key benchmarks for testing stellar structure and evolution across different ages and activity levels.

Their detailed characterization helps place the Sun in context within the broader population of solar-like stars. This study presents the characterization of six seismic solar analogs observed by the NASA Kepler and K2 missions. Combining asteroseismic constraints from space-based photometry with high-resolution spectroscopy and Gaia astrometry, we derived their fundamental parameters and assessed their resemblance to the Sun.

Global seismic properties and individual oscillation modes were extracted from the photometric light curves, while atmospheric parameters were obtained from data collected by the HERMES spectrograph at the Mercator telescope. Stellar modeling using seven independent stellar evolution codes yielded consistent masses, radii, and ages.

These stars have masses between 0.91 and 1.04~M_⊙, radii between 0.95 and 1.08~R_⊙, and ages from about 1.8 to 9.1~Gyr, with typical systematic uncertainties of ± 0.02~M_⊙, ± 0.01~R_⊙, and ± 0.7~Gyr, respectively. One star, EPIC~206064678, exhibits properties very similar to those of the Sun, with M=1.016±0.033M_⊙, R=0.990±0.011R_⊙, and an age of 5.40±0.12,Gyr. It can therefore be considered a close solar twin, although it is slightly older and more metal-rich (0.25±0.07,dex).

Four targets display binarity signatures and all exhibit very low chromospheric activity. This work broadens the sample of well-characterized seismic solar analogs towards a larger sample of metallicities and ages, providing new references for comparative stellar studies and future asteroseismic investigations.

R. A. García, S. Mathur, G. T. Hookway, D. Godoy-Rivera, T. Masseron, J. Bétrisey, G. Buldgen, C. Lindsay, T. S. Metcalfe, O. J. Scutt, A. Stokholm, P. G. Beck, O. Benomar, G. R. Davies, A. Jiménez, J. Merc, M. B. Nielsen, E. Panetier, F. Pérez Hernández, L. Borg, S. N. Breton, L. Debacker, A. Escorza, D. H. Grossmann, A. Hamy, B. Liagre, M. N. Lund, S. Mathis, D.B. Palakkatharappil, A. R. G. Santos, V. Delsanti, L. González-Cuesta, V. Fox, N. Proust

Comments: Accepted for publication in A&A. 17 pages, 11 figures
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2604.27090 [astro-ph.SR] (or arXiv:2604.27090v1 [astro-ph.SR] for this version)
https://doi.org/10.48550/arXiv.2604.27090
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Submission history
From: Rafael A. Garcia
[v1] Wed, 29 Apr 2026 18:33:01 UTC (5,438 KB)
https://arxiv.org/abs/2604.27090

Astrobiology, stellar cartography,

Keith Cowing

Biologist, Explorers Club Fellow, ex-NASA Space Biologist and Payload integrator, Editor of NASAWatch.com and Astrobiology.com, Lapsed climber, Explorer, Synaesthete, Former Challenger Center board member 🖖🏻

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