X-Shooting ULLYSES: Massive stars at low metallicity

Massive stars drive the ionization and mechanical feedback within young star-forming regions. The Large Magellanic Cloud (LMC) is an ideal galaxy for studying individual massive stars and quantifying their feedback contribution to the environment. We analyze eight exemplary targets in LMC N11 B from the Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) program using novel spectra from HST ( COS and STIS ) in the UV, and from VLT (X-shooter) in the optical. We model the spectra of early to late O-type stars using state-of-the-art PoWR atmosphere models. We determine the stellar and wind parameters (e.g., T ⋆ , log g, L ⋆ , Ṁ , and v ∞ ) of the analyzed objects, chemical abundances (C, N, and O), ionizing and mechanical feedback ( Q H , Q HeI , Q He II , and L mec ), and X-rays. We report ages of 2–4.5 Myr and masses of 30–60 M ⊙ for the analyzed stars in N11 B, which are consistent with a scenario of sequential star formation. We note that the observed wind-momentum–luminosity relation is consistent with theoretical predictions. We detect nitrogen enrichment by up to a factor of seven in most of the stars. However, we do not find a correlation between nitrogen enrichment and projected rotational velocity. Finally, based on their spectral type, we estimate the total ionizing photons injected from the O-type stars in N11 B into its environment. We report log (Σ Q H ) = 50.5 ph s −1 , log (Σ Q He I ) = 49.6 ph s −1 , and log (Σ Q He II )= 44.4 ph s −1 , consistent with the total ionizing budget in N11.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-02-18
DOI
https://doi.org/10.1051/0004-6361/202451366
Citations
4
Primary Topic
Astrophysics and Star Formation Studies
Type
article
Field-Weighted Citation Impact
4.62

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article

X-Shooting ULLYSES: Massive stars at low metallicity

L. Mahy, P. A. Crowther, Aida Wofford, V. M. A. Gómez-González et al.
4 citations
Astronomy and Astrophysics
Astrophysics and Star Formation Studies
4.62
article

X-Shooting ULLYSES: Massive stars at low metallicity

L. Mahy, P. A. Crowther, Aida Wofford, V. M. A. Gómez-González, H. Todt, A. Mehner, S. R. Berlanas, J. S. Vink, Jacco Th. van Loon, Anna F. McLeod, Claus Leitherer, C. Kehrig, F. Tramper, O. Grace Telford, S. Reyero Serantes, V. Ramachandran, A. C. Gormaz-Matamala, T. Shenar, A. A. C. Sander, W.‐R. Hamann, L. M. Oskinova, N. Morrell, Asif ud‐Doula, M. Bernini-Peron, D. Pauli, R. Kuiper
article en
4 citations

Abstract

Massive stars drive the ionization and mechanical feedback within young star-forming regions. The Large Magellanic Cloud (LMC) is an ideal galaxy for studying individual massive stars and quantifying their feedback contribution to the environment. We analyze eight exemplary targets in LMC N11 B from the Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) program using novel spectra from HST ( COS and STIS ) in the UV, and from VLT (X-shooter) in the optical. We model the spectra of early to late O-type stars using state-of-the-art PoWR atmosphere models. We determine the stellar and wind parameters (e.g., T ⋆ , log g, L ⋆ , Ṁ , and v ∞ ) of the analyzed objects, chemical abundances (C, N, and O), ionizing and mechanical feedback ( Q H , Q HeI , Q He II , and L mec ), and X-rays. We report ages of 2–4.5 Myr and masses of 30–60 M ⊙ for the analyzed stars in N11 B, which are consistent with a scenario of sequential star formation. We note that the observed wind-momentum–luminosity relation is consistent with theoretical predictions. We detect nitrogen enrichment by up to a factor of seven in most of the stars. However, we do not find a correlation between nitrogen enrichment and projected rotational velocity. Finally, based on their spectral type, we estimate the total ionizing photons injected from the O-type stars in N11 B into its environment. We report log (Σ Q H ) = 50.5 ph s −1 , log (Σ Q He I ) = 49.6 ph s −1 , and log (Σ Q He II )= 44.4 ph s −1 , consistent with the total ionizing budget in N11.

Astronomy and AstrophysicsVol. 695
University of Scranton (US), Space Telescope Science Institute (US), Pennsylvania State University (US), Universidad de La Laguna (ES), Pontificia Universidad Católica de Chile (CL), Tel Aviv University (IL), University of Potsdam (DE), Durham University (GB), Carnegie Institution for Science (US), Princeton University (US), Adolfo Ibáñez University (CL), Heidelberg University (DE), Royal Observatory of Belgium (BE), Armagh Observatory & Planetarium (GB), Czech Academy of Sciences, Astronomical Institute (CZ), Ensenada Institute of Technology (MX), Université Bourgogne Franche-Comté (FR), Carnegie Observatories (US), Centro de Astrobiología (ES), European Southern Observatory (CL), Instituto de Astrofísica de Canarias (ES), Las Campanas Observatory (CL), Instituto de Astrofísica de Andalucía (ES), Keele University (GB), University of Duisburg-Essen (DE), University of Sheffield (GB)
Smithsonian Institution, National Aeronautics and Space Administration, Space Telescope Science Institute, European Space Agency, Deutsche Forschungsgemeinschaft, Bundesministerium für Bildung und Forschung, Nuclear Safety and Security Commission, European Southern Observatory, Smithsonian Astrophysical Observatory, HORIZON EUROPE Framework Programme
Openalex Percentile: Top 6%
Astrophysics and Star Formation Studies
4.62
DOIOpen Access PDFOpenAlex
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