_version_ 1866909572657053696
author Roman-Duval, Julia
Fischer, William J.
Fullerton, Alexander W.
Taylor, Jo
Plesha, Rachel
Proffitt, Charles
Monroe, TalaWanda
Fischer, Travis C.
Aloisi, Alessandra
Bouret, Jean-Claude
Britt, Christopher
Calvet, Nuria
Carlberg, Joleen K.
Crowther, Paul A.
De Rosa, Gisella
Dixon, William V.
Espaillat, Catherine C.
Evans, Christopher J.
Fox, Andrew J.
France, Kevin
Garcia, Miriam
Fleming, Sott W.
Frazer, Elaine M.
De Castro, Ana I. Gómez
Herczeg, Gregory J.
Hernandez, Svea
Hirschauer, Alec S.
James, Bethan L.
Johns-Krull, Christopher M.
Leitherer, Claus
Lockwood, Sean
Najita, Joan
Oey, M. S.
Oliveira, Cristina
Pauly, Tyler
Reid, I. Neill
Riedel, Adric
Rodriguez, David R.
Sahnow, David
Sankrit, Ravi
Sembach, Kenneth R.
Shaw, Richard
Smith, Linda J.
Sohn, S. Tony
Som, Debopam
Úbeda, Leonardo
Welty, Daniel E.
author_facet Roman-Duval, Julia
Fischer, William J.
Fullerton, Alexander W.
Taylor, Jo
Plesha, Rachel
Proffitt, Charles
Monroe, TalaWanda
Fischer, Travis C.
Aloisi, Alessandra
Bouret, Jean-Claude
Britt, Christopher
Calvet, Nuria
Carlberg, Joleen K.
Crowther, Paul A.
De Rosa, Gisella
Dixon, William V.
Espaillat, Catherine C.
Evans, Christopher J.
Fox, Andrew J.
France, Kevin
Garcia, Miriam
Fleming, Sott W.
Frazer, Elaine M.
De Castro, Ana I. Gómez
Herczeg, Gregory J.
Hernandez, Svea
Hirschauer, Alec S.
James, Bethan L.
Johns-Krull, Christopher M.
Leitherer, Claus
Lockwood, Sean
Najita, Joan
Oey, M. S.
Oliveira, Cristina
Pauly, Tyler
Reid, I. Neill
Riedel, Adric
Rodriguez, David R.
Sahnow, David
Sankrit, Ravi
Sembach, Kenneth R.
Shaw, Richard
Smith, Linda J.
Sohn, S. Tony
Som, Debopam
Úbeda, Leonardo
Welty, Daniel E.
contents Specifically selected to leverage the unique ultraviolet capabilities of the Hubble Space Telescope, the Hubble Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) is a Director's Discretionary program of approximately 1000 orbits - the largest ever executed - that produced a UV spectroscopic library of O and B stars in nearby low metallicity galaxies and accreting low mass stars in the Milky Way. Observations from ULLYSES combined with archival spectra uniformly sample the fundamental astrophysical parameter space for each mass regime, including spectral type, luminosity class, and metallicity for massive stars, and the mass, age, and disk accretion rate for low-mass stars. The ULLYSES spectral library of massive stars will be critical to characterize how massive stars evolve at different metallicities; to advance our understanding of the production of ionizing photons, and thus of galaxy evolution and the re-ionization of the Universe; and to provide the templates necessary for the synthesis of integrated stellar populations. The massive star spectra are also transforming our understanding of the interstellar and circumgalactic media of low metallicity galaxies. On the low-mass end, UV spectra of T Tauri stars contain a plethora of diagnostics of accretion, winds, and the warm disk surface. These diagnostics are crucial for evaluating disk evolution and provide important input to assess atmospheric escape of planets and to interpret powerful probes of disk chemistry, as observed with ALMA and JWST. In this paper we motivate the design of the program, describe the observing strategy and target selection, and present initial results.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05446
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Large Director's Discretionary Program with Hubble. I. Goals, Design, and Initial Results
Roman-Duval, Julia
Fischer, William J.
Fullerton, Alexander W.
Taylor, Jo
Plesha, Rachel
Proffitt, Charles
Monroe, TalaWanda
Fischer, Travis C.
Aloisi, Alessandra
Bouret, Jean-Claude
Britt, Christopher
Calvet, Nuria
Carlberg, Joleen K.
Crowther, Paul A.
De Rosa, Gisella
Dixon, William V.
Espaillat, Catherine C.
Evans, Christopher J.
Fox, Andrew J.
France, Kevin
Garcia, Miriam
Fleming, Sott W.
Frazer, Elaine M.
De Castro, Ana I. Gómez
Herczeg, Gregory J.
Hernandez, Svea
Hirschauer, Alec S.
James, Bethan L.
Johns-Krull, Christopher M.
Leitherer, Claus
Lockwood, Sean
Najita, Joan
Oey, M. S.
Oliveira, Cristina
Pauly, Tyler
Reid, I. Neill
Riedel, Adric
Rodriguez, David R.
Sahnow, David
Sankrit, Ravi
Sembach, Kenneth R.
Shaw, Richard
Smith, Linda J.
Sohn, S. Tony
Som, Debopam
Úbeda, Leonardo
Welty, Daniel E.
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Specifically selected to leverage the unique ultraviolet capabilities of the Hubble Space Telescope, the Hubble Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) is a Director's Discretionary program of approximately 1000 orbits - the largest ever executed - that produced a UV spectroscopic library of O and B stars in nearby low metallicity galaxies and accreting low mass stars in the Milky Way. Observations from ULLYSES combined with archival spectra uniformly sample the fundamental astrophysical parameter space for each mass regime, including spectral type, luminosity class, and metallicity for massive stars, and the mass, age, and disk accretion rate for low-mass stars. The ULLYSES spectral library of massive stars will be critical to characterize how massive stars evolve at different metallicities; to advance our understanding of the production of ionizing photons, and thus of galaxy evolution and the re-ionization of the Universe; and to provide the templates necessary for the synthesis of integrated stellar populations. The massive star spectra are also transforming our understanding of the interstellar and circumgalactic media of low metallicity galaxies. On the low-mass end, UV spectra of T Tauri stars contain a plethora of diagnostics of accretion, winds, and the warm disk surface. These diagnostics are crucial for evaluating disk evolution and provide important input to assess atmospheric escape of planets and to interpret powerful probes of disk chemistry, as observed with ALMA and JWST. In this paper we motivate the design of the program, describe the observing strategy and target selection, and present initial results.
title The UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Large Director's Discretionary Program with Hubble. I. Goals, Design, and Initial Results
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2504.05446