Hubble’s three-year study under the ULLYSES program enters a new chapter.

The ULLYSES program embarked on a comprehensive investigation into the diverse population of young stars, focusing on two distinct categories: the scorching super-hot, massive, blue stars, and their cooler, redder counterparts, which are less massive than our Sun. Illustrating this stellar diversity, the top panel presents a captivating Hubble Space Telescope image capturing a star-forming enclave within 30 Doradus, the Tarantula Nebula. Situated amidst the ethereal expanse of the Large Magellanic Cloud, this celestial crucible teems with the brilliance of massive, youthful blue stars, serving as a prime target for ULLYSES’ probing gaze. In contrast, the bottom panel offers an artist’s rendition of a cooler, redder, young star, characterized by its subtle hues and serene demeanor. Despite its lesser mass compared to our Sun, this stellar entity is in the midst of an evolutionary ballet, as it steadily accrues material from its surrounding planetary disk, sculpting the cosmic tapestry of planetary formation. Together, these snapshots encapsulate the multifaceted nature of stellar youth under ULLYSES’ scrutinous examination, shedding light on the intricacies of cosmic birth and evolution.

In a monumental undertaking, scientists and engineers embarked on the ULLYSES (Ultraviolet Legacy Library of Young Stars as Essential Standards) project, utilizing the Hubble Space Telescope to gather data on nearly 500 stars across a span of three years. This ambitious endeavor delves into the formation, evolution, and influence of stars within their cosmic surroundings, offering invaluable insights into various realms of astrophysics.

Completed in December 2023, the ULLYSES survey yields a wealth of spectroscopic data captured in ultraviolet light, a domain accessible only from space, rendering Hubble the sole instrument capable of executing such research endeavors.

Julia Roman-Duval, the Implementation Team Lead for ULLYSES at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, envisions ULLYSES as a transformative initiative with far-reaching implications for astrophysics, spanning from exoplanetary studies to the intricate interplay between massive stars and galaxy evolution, and even shedding light on the earliest epochs of cosmic evolution.

The ULLYSES initiative encompasses a meticulous examination of 220 stars alongside data amalgamated from the Hubble archive on 275 additional stars. Complementing these observations are contributions from leading ground-based telescopes and X-ray space telescopes, furnishing a comprehensive dataset encapsulating stellar spectra and crucial parameters such as temperature, chemical composition, and rotational dynamics.

Among the stars scrutinized under ULLYSES are super-hot, massive, blue stars, emitting ultraviolet radiation that holds vital clues about the velocity of their formidable stellar winds. These winds play a pivotal role in galactic evolution, dispersing essential elements synthesized within stellar cores into the interstellar medium, thus shaping the chemical composition of galaxies and facilitating the formation of new stars and planetary systems.

Another focal point of ULLYSES is the investigation of young stars less massive than our Sun, characterized by their prodigious emission of high-energy radiation, including ultraviolet light and X-rays. These nascent stars, ensconced within their circumstellar disks of gas and dust, offer invaluable insights into the processes governing star formation and planetary accretion, influencing the habitability of nascent planets.

The genesis of the ULLYSES concept stemmed from a collaborative effort by a panel of experts, aiming to harness the capabilities of Hubble to establish a legacy repository of stellar observations. This vision was further augmented by synergistic partnerships with other observatories, both ground-based and spaceborne, amplifying the scope and depth of the project.

To foster collaborative research and maximize the utilization of the ULLYSES dataset, STScI organized a workshop, providing a platform for astronomers to exchange ideas, refine analyses, and unearth novel avenues of investigation. This collaborative ethos underscores the commitment to leveraging the full potential of the ULLYSES legacy, ushering in a new era of discovery in the realm of young stellar systems.

As Hubble continues to unveil the mysteries of the cosmos, ULLYSES stands as a testament to the power of international collaboration and the insatiable human quest for understanding the universe’s celestial wonders. Through endeavors like ULLYSES, humanity inches closer to unraveling the enigmatic tapestry of cosmic evolution, one stellar spectrum at a time.