Hubble telescope unexpectedly finds hot accretion disk in FU Orionis
NASA’s Hubble Space Telescope has provided new insights into the young star FU Orionis, located in the constellation Orion. Observations have revealed extreme temperatures in the inner region of the accretion disk, challenging current models of stellar accretion. Using Hubble’s Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph, astronomers captured far-ultraviolet and near-ultraviolet spectra, showing that the inner edge of the disk was unexpectedly hot, with temperatures reaching 16,000 Kelvin – almost three times the surface temperature of the Sun.
The bright outburst of a star explained
First observed in 1936, FU Orionis became a hundred times brighter in months and remains a unique object of photography. study. Unlike typical T Tauri stars, the accretion disk hits the star’s surface due to instability. These are caused by the large mass of the disk, interactions with companion stars, or material falling inward. Lynne Hillenbrand, a co-author from Caltech, said in a statement that the observed ultraviolet brightness exceeded predictions and revealed a highly dynamic interface between the star and its disk.
Implications for planet formation
According to one report by NASA, the study has significant implications for planetary systems that form around such stars. The report further quoted Adolfo Carvalho, lead author of the study, as saying that while distant planets in the disk may experience altered chemical composition due to outbursts, planets that form close to the star may experience disruption or destruction. This revised model provides critical insights into the survival of rocky planets in young galaxies, he added.
Future research on FU Orionis
The research team continues to investigate the spectral emission lines in the collected data, with the aim of mapping the gas movements in the inner regions of the star. Hillenbrand noted that FU Orionis offers a unique opportunity to study the mechanisms at play in erupting young stars. These findings, published in The Astrophysical Journal Letters, demonstrate the continued value of Hubble’s ultraviolet capabilities in advancing stellar science.
