Early stages of the FU Orionis outburst (artist’s concept)

This is an artist’s concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. A team of astronomers has used the NASA/ESA Hubble Space Telescope’s ultraviolet capabilities to learn more about the interaction between FU Ori’s stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. They found that the inner disc, touching the star, is much hotter than expected—16,000 kelvins—nearly three times our Sun’s surface temperature. That sizzling temperature is nearly twice as hot as previously believed.

[Image description: Artist’s concept of the early stages of the young star FU Orionis outburst. The star, a bright yellow sphere near the center, and its fluffy disk of gas and dust are slightly tilted, extending from the top left corner to the bottom right. The swirling disk is bright yellow close to the star and gradually transitions to dark orange moving toward the edges of the frame. The top left and right corners reveal a black, starless background.]