Astronomers using the NASA/ESA Hubble Space Telescope have collected information on almost 500 stars as part of the Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) survey.
“I believe the ULLYSES project will be transformative, impacting overall astrophysics — from exoplanets, to the effects of massive stars on galaxy evolution, to understanding the earliest stages of the evolving Universe,” said ULLYSES implementation team lead Dr. Julia Roman-Duval, an astronomer at the Space Telescope Science Institute.
“Aside from the specific goals of the survey, the stellar data can also be used in fields of astrophysics in ways we can’t yet imagine.”
Dr. Roman-Duval and her colleagues studied 220 stars, then combined those observations with information from the Hubble archive on 275 additional stars.
The survey also included data from some of the world’s largest, most powerful ground-based telescopes and X-ray space telescopes.
The ULLYSES dataset is made up of stellar spectra, which carry information about each star’s temperature, chemical composition, and rotation.
One type of stars studied under ULLYSES is super-hot, massive, blue stars.
They are a million times brighter than the Sun and glow fiercely in ultraviolet light that can easily be detected by Hubble. Their spectra include key diagnostics of the speed of their powerful winds.
The winds drive galaxy evolution and seed galaxies with the elements needed for life. Those elements are cooked up inside the stars’ nuclear fusion ovens and then injected into space as a star dies.
ULLYSES targeted blue stars in nearby galaxies that are deficient in elements heavier than helium and hydrogen.
“ULLYSES observations are a stepping stone to understanding those first stars and their winds in the Universe, and how they impact the evolution of their young host galaxy,” Dr. Roman-Duval said.
The other star category in the ULLYSES survey is young stars less massive than our…
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