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Unveiling the nature of HE 0107-5240:: a long period binary CEMP-no star with [Fe/H] of -5.56

Methods. We derived radial velocities using cross-correlation with a template, taking advantage of the strong G-band feature. We combined all observations to obtain a high signal-to-noise ratio spectrum, which we used to refine our understanding of the stellar chemical composition. We additionally u...

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Main Authors: Caffau, Elisabetta (Author) , Steffen, M. (Author) , Molaro, P. (Author) , Bonifacio, P. (Author) , Christlieb, Norbert (Author) , Aguado, D. S. (Author) , González Hernández, J. I. (Author) , Zapatero Osorio, M. R. (Author) , Monaco, L. (Author) , Limongi, M. (Author) , Chieffi, A. (Author) , Falla, A. (Author) , Roberti, L. (Author) , Gallagher, A. J. (Author) , Spite, M. (Author) , François, P. (Author) , Ludwig, Hans-Günter (Author) , Sbordone, L. (Author) , Lallement, R. (Author) , Allende Prieto, C. (Author) , Rebolo, R. (Author) , Cristiani, S. (Author) , Cupani, G. (Author) , D’Odorico, V. (Author) , Martins, C. J. A. P. (Author) , Milaković, D. (Author) , Murphy, M. T. (Author) , Nunes, N. J. (Author) , Santos, N. C. (Author) , Schmidt, T. M. (Author)
Format: Article (Journal)
Language:English
Published: 18 December 2025
In: Astronomy and astrophysics
Year: 2025, Volume: 704, Pages: 1-16
ISSN:1432-0746
DOI:10.1051/0004-6361/202556891
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1051/0004-6361/202556891
Verlag, kostenfrei, Volltext: https://www.aanda.org/10.1051/0004-6361/202556891
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Author Notes:E. Caffau, M. Steffen, P. Molaro, P. Bonifacio, N. Christlieb, D. S. Aguado, J. I. González Hernández, M. R. Zapatero Osorio, L. Monaco, M. Limongi, A. Chieffi, A. Falla, L. Roberti, A. J. Gallagher, M. Spite, P. François, H.-G. Ludwig, L. Sbordone, R. Lallement, C. Allende Prieto, R. Rebolo, S. Cristiani, G. Cupani, V. D’Odorico, C. J. A. P. Martins, D. Milaković, M. T. Murphy, N. J. Nunes, N. C. Santos, and T. M. Schmidt
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Summary:Methods. We derived radial velocities using cross-correlation with a template, taking advantage of the strong G-band feature. We combined all observations to obtain a high signal-to-noise ratio spectrum, which we used to refine our understanding of the stellar chemical composition. We additionally used a co-added UVES spectrum in the blue to complement the wavelength coverage of ESPRESSO. - Results. Observations of HE 0107−5240 over a span of more than four years yield a revised orbital period of about 29 years. We provide updated elemental abundances for Sc, Cr, Co, and, tentatively, Al, along with a new upper limit for Be. We derive the iron abundance from ionised Fe lines and establish significant upper limits for Li, Si, and Sr. - Conclusions. We confirm that the star is a long-period binary. Iron abundances derived from neutral and ionised lines are consistent with the local thermodynamical equilibrium (LTE) assumption, which casts doubt on published deviations from LTE corrections for Fe in this star. The heavy elements Sr and Ba remain undetected, confirming the classification of HE 0107−5240 as a carbon-enhanced, metal-poor star not enhanced in heavy elements (CEMP-no), and supporting the absence of an n-capture element plateau at the lowest metallicities.
Item Description:Gesehen am 22.06.2026
Physical Description:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/202556891

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