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Abstract EANA2025-147


Habitability and elemental abundances: the case of Phosphorus in our Galactic neighborhood

Dr. Dario Esposito (corr-auth) (1) , Prof. Giovanni Covone (2) , Prof. Paola Manini (3), Prof. Donato Giovannelli (4) , Dr. Christian Magliano (2) , Dr. Luca Cacciapuoti (5) , Dr. Victor M. Rivilla (6) , Dr. Vito Saggese (2) , Prof. Leonardo Testi (7) , Dr. Emanuele Cristiano (8), Dr. Luca Tonietti (9)
(1) Scuola Superiore Meridionale, Naples (2) Department of Physics “Ettore Pancini”, University of Naples Federico II, Naples, Italy - INAF, Osservatorio Astronomico di Capodimonte, Naples (3) Departent of Chemical Sciences, University of Naples Federico II, Naples (4) Department of Biology, University of Naples Federico II, Naples, Italy. - Marine Chemistry & Geochemistry Department, Woods Hole Oceanographic Institution, USA (5) European Southern Observatory, Chile (6) Centro de Astrobiología (CAB), INTA-CSIC, Madrid, Spain (7) Alma Mater Studiorum -- Università di Bologna, Dipartimento di Fisica e Astronomia ``Augusto Righi'', Bologna (8) Department of Biology, University of Naples Federico II, Naples, Italy (9) epartment of Science and Technology, Parthenope University of Naples, Italy


Phosphorus (P) is a vital ingredient for life as we know it—essential to the backbone of DNA, the structure of cell membranes, and the function of metabolic molecules like ATP. Yet, among the bio-essential CHNOPS elements, phosphorus is notably rare in the cosmos and notoriously difficult to observe. In this talk, we present a detailed analysis of phosphorus abundances in a sample of 233 FGK-type stars within the solar neighborhood, using high-quality data from the Hypatia Catalog.

Our results reveal a [P/Fe] trend with [Fe/H] that mimics that of α-elements, pointing toward a dominant origin in Type II supernovae. However, subtle deviations from the classical α-behavior suggest additional or alternative nucleosynthetic sources may contribute to galactic P production. Interestingly, we observe tight correlations between P and other CHNOPS elements, implying that phosphorus-rich stars may offer environments with enhanced chemical resources for potential biospheres.

When comparing Galactic populations, we find that stars in the thin disk systematically exhibit higher abundances of several key elements compared to their thick disk counterparts. This suggests that the thin disk may provide more chemically fertile conditions for the development of life-supporting planets. Furthermore, a preliminary comparison between known planet-hosting stars and non-hosts hints at a modest enrichment in oxygen, magnesium, silicon, and iron-peak elements among the hosts. Although the small sample size of planet-hosting stars in our study (N = 14) prevents definitive conclusions, the trend aligns with broader findings linking elemental composition to planet formation likelihood.

We also explore molar ratios relevant to planetary mineralogy, focusing on P/Mg, P/Si, and P/O. We find that the Solar values of P/Mg and P/Si are broadly representative of local stellar populations, supporting the idea that Earth-like planetary compositions may be common. However, the relatively high solar P/O ratio stands out and may have enhanced phosphorus bioavailability on early Earth—an intriguing clue in the search for habitable conditions elsewhere.

This study provides one of the first systematic investigations into stellar phosphorus abundances from an astrobiological perspective. By linking elemental abundance patterns to galactic environment and planetary building blocks, we aim to contextualize phosphorus—and life’s chemistry—within the broader framework of the Milky Way. These findings underscore the importance of stellar chemistry in assessing the potential habitability of planetary systems and offer new insight into the cosmic distribution of life’s essential elements.