{"date_updated":"2023-08-21T12:04:58Z","month":"12","title":"A panchromatic study of massive stars in the extremely metal-poor local group dwarf galaxy Leo A","scopus_import":"1","article_processing_charge":"No","keyword":["Space and Planetary Science","Astronomy and Astrophysics"],"date_created":"2023-08-03T10:10:25Z","article_number":"206","type":"journal_article","citation":{"mla":"Gull, Maude, et al. “A Panchromatic Study of Massive Stars in the Extremely Metal-Poor Local Group Dwarf Galaxy Leo A.” <i>The Astrophysical Journal</i>, vol. 941, no. 2, 206, American Astronomical Society, 2022, doi:<a href=\"https://doi.org/10.3847/1538-4357/aca295\">10.3847/1538-4357/aca295</a>.","ista":"Gull M, Weisz DR, Senchyna P, Sandford NR, Choi Y, McLeod AF, El-Badry K, Götberg YLL, Gilbert KM, Boyer M, Dalcanton JJ, GuhaThakurta P, Goldman S, Marigo P, McQuinn KBW, Pastorelli G, Stark DP, Skillman E, Ting Y, Williams BF. 2022. A panchromatic study of massive stars in the extremely metal-poor local group dwarf galaxy Leo A. The Astrophysical Journal. 941(2), 206.","short":"M. Gull, D.R. Weisz, P. Senchyna, N.R. Sandford, Y. Choi, A.F. McLeod, K. El-Badry, Y.L.L. Götberg, K.M. Gilbert, M. Boyer, J.J. Dalcanton, P. GuhaThakurta, S. Goldman, P. Marigo, K.B.W. McQuinn, G. Pastorelli, D.P. Stark, E. Skillman, Y. Ting, B.F. Williams, The Astrophysical Journal 941 (2022).","ieee":"M. Gull <i>et al.</i>, “A panchromatic study of massive stars in the extremely metal-poor local group dwarf galaxy Leo A,” <i>The Astrophysical Journal</i>, vol. 941, no. 2. American Astronomical Society, 2022.","ama":"Gull M, Weisz DR, Senchyna P, et al. A panchromatic study of massive stars in the extremely metal-poor local group dwarf galaxy Leo A. <i>The Astrophysical Journal</i>. 2022;941(2). doi:<a href=\"https://doi.org/10.3847/1538-4357/aca295\">10.3847/1538-4357/aca295</a>","apa":"Gull, M., Weisz, D. R., Senchyna, P., Sandford, N. R., Choi, Y., McLeod, A. F., … Williams, B. F. (2022). A panchromatic study of massive stars in the extremely metal-poor local group dwarf galaxy Leo A. <i>The Astrophysical Journal</i>. American Astronomical Society. <a href=\"https://doi.org/10.3847/1538-4357/aca295\">https://doi.org/10.3847/1538-4357/aca295</a>","chicago":"Gull, Maude, Daniel R. Weisz, Peter Senchyna, Nathan R. Sandford, Yumi Choi, Anna F. McLeod, Kareem El-Badry, et al. “A Panchromatic Study of Massive Stars in the Extremely Metal-Poor Local Group Dwarf Galaxy Leo A.” <i>The Astrophysical Journal</i>. American Astronomical Society, 2022. <a href=\"https://doi.org/10.3847/1538-4357/aca295\">https://doi.org/10.3847/1538-4357/aca295</a>."},"oa_version":"Published Version","article_type":"original","extern":"1","status":"public","issue":"2","publisher":"American Astronomical Society","publication_identifier":{"eissn":["1538-4357"],"issn":["0004-637X"]},"abstract":[{"text":"We characterize massive stars (M > 8 M⊙) in the nearby (D ∼ 0.8 Mpc) extremely metal-poor (Z ∼ 5% Z⊙) galaxy Leo A using Hubble Space Telescope ultraviolet (UV), optical, and near-infrared (NIR) imaging along with Keck/Low-Resolution Imaging Spectrograph and MMT/Binospec optical spectroscopy for 18 main-sequence OB stars. We find that: (a) 12 of our 18 stars show emission lines, despite not being associated with an H ii region, suggestive of stellar activity (e.g., mass loss, accretion, binary star interaction), which is consistent with previous predictions of enhanced activity at low metallicity; (b) six are Be stars, which are the first to be spectroscopically studied at such low metallicity—these Be stars have unusual panchromatic SEDs; (c) for stars well fit by the TLUSTY nonlocal thermodynamic equilibrium models, the photometric and spectroscopic values of $\\mathrm{log}({T}_{\\mathrm{eff}})$ and $\\mathrm{log}(g)$ agree to within ∼0.01 dex and ∼0.18 dex, respectively, indicating that near-UV/optical/NIR imaging can be used to reliably characterize massive (M ∼ 8–30 M⊙) main-sequence star properties relative to optical spectroscopy; (d) the properties of the most-massive stars in H II regions are consistent with constraints from previous nebular emission line studies; and (e) 13 stars with M > 8M⊙ are >40 pc from a known star cluster or H II region. Our sample comprises ∼50% of all known massive stars at Z ≲ 10% Z⊙with derived stellar parameters, high-quality optical spectra, and panchromatic photometry.","lang":"eng"}],"year":"2022","_id":"13451","volume":941,"author":[{"last_name":"Gull","full_name":"Gull, Maude","first_name":"Maude"},{"first_name":"Daniel R.","full_name":"Weisz, Daniel R.","last_name":"Weisz"},{"first_name":"Peter","full_name":"Senchyna, Peter","last_name":"Senchyna"},{"last_name":"Sandford","full_name":"Sandford, Nathan R.","first_name":"Nathan R."},{"last_name":"Choi","full_name":"Choi, Yumi","first_name":"Yumi"},{"first_name":"Anna F.","last_name":"McLeod","full_name":"McLeod, Anna F."},{"last_name":"El-Badry","full_name":"El-Badry, Kareem","first_name":"Kareem"},{"first_name":"Ylva Louise Linsdotter","last_name":"Götberg","full_name":"Götberg, Ylva Louise Linsdotter","id":"d0648d0c-0f64-11ee-a2e0-dd0faa2e4f7d","orcid":"0000-0002-6960-6911"},{"first_name":"Karoline M.","last_name":"Gilbert","full_name":"Gilbert, Karoline M."},{"first_name":"Martha","full_name":"Boyer, Martha","last_name":"Boyer"},{"full_name":"Dalcanton, Julianne J.","last_name":"Dalcanton","first_name":"Julianne J."},{"first_name":"Puragra","full_name":"GuhaThakurta, Puragra","last_name":"GuhaThakurta"},{"first_name":"Steven","last_name":"Goldman","full_name":"Goldman, Steven"},{"full_name":"Marigo, Paola","last_name":"Marigo","first_name":"Paola"},{"full_name":"McQuinn, Kristen B. W.","last_name":"McQuinn","first_name":"Kristen B. W."},{"last_name":"Pastorelli","full_name":"Pastorelli, Giada","first_name":"Giada"},{"first_name":"Daniel P.","full_name":"Stark, Daniel P.","last_name":"Stark"},{"full_name":"Skillman, Evan","last_name":"Skillman","first_name":"Evan"},{"first_name":"Yuan-sen","last_name":"Ting","full_name":"Ting, Yuan-sen"},{"first_name":"Benjamin F.","full_name":"Williams, Benjamin F.","last_name":"Williams"}],"doi":"10.3847/1538-4357/aca295","external_id":{"arxiv":["2211.14349"]},"publication_status":"published","day":"27","publication":"The Astrophysical Journal","date_published":"2022-12-27T00:00:00Z","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","language":[{"iso":"eng"}],"quality_controlled":"1","intvolume":"       941","main_file_link":[{"url":"https://doi.org/10.3847/1538-4357/aca295","open_access":"1"}],"oa":1}