Hubble’s ULLYSES program will observe the ultraviolet light stars emit—and spread that light into its component wavelengths, which are known as spectra. This graph, which shows two spectra, maps how much far-ultraviolet light the two stars are emitting through the gas in their surrounding galaxies. The star in the dwarf galaxy Sextans A, represented in purple, has emitted light, but there isn’t much gas nearby absorbing it. In contrast, the star in the Large Magellanic Cloud, represented in teal, shows that there is sulfur blocking some of its light. By analyzing the elements between us and the stars, researchers can learn about the conditions and history of the gas and dust surrounding stars in distant galaxies.
