Hubble Space Telescope reveals unexpected characteristics of the young star FU Orionis in the constellation Orion. Astronomers detected an extremely hot disk that exists around it, with temperatures up to 16,000 kelvins. The measured value is about three times hotter than the Sun’s surface and seriously contradicts current theoretical models of stellar accretion.
Hubble’s Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph provided scientists a chance to study ultraviolet spectra. These instruments offered unprecedented insight into the innermost reaches of the disk, where extreme temperatures reveal dynamic interactions between the disk and the star itself.
FU Orionis: A Star Like No Other
Astronomers noticed FU Orionis in 1936, when the star became 100 times brighter within months. It is one of the oddball young stars of its type – like T Tauri stars. In FU Orionis, the accretion disk lies on the surface of the star because of instability.
This instability arises from several factors, including the disk’s massive size, interactions with companion stars, or material falling inward. Observations show ultraviolet emissions exceeding predictions, highlighting an energetic and dynamic interface between the disk and the star.
Planetary Formation Under Threat
These results are of prime importance to the issue of planet formation around eruptive stars like FU Orionis. This means that extreme outbursts set up new chemical compositions for otherwise distant planets in the disk. Planets closer to the star, however, face downright disastrous ends: destruction.
Lead author Adolfo Carvalho stressed that this research is crucial in learning about rocky planet survival in such hostile environments. This knowledge is furthering our understanding of planetary system evolution and helping tune models of early star systems.
Hubble’s ultraviolet instruments continue to advance understanding of stellar phenomena. The ability of the telescope to capture far-ultraviolet and near-ultraviolet spectra is essential for the study of dynamic systems, such as FU Orionis.
The team plans to continue further studies of the spectral emission lines to understand the movement of gas in the inner regions of the star. These discoveries contribute to a better understanding of the mechanisms that govern eruptive young stars.
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Shaping the Future of Stellar Science
The findings of Hubble surrounding FU Orionis illuminate critical proc esses that are violent in the formation of stellar systems and their young stars. As astronomers hone in on their understanding, they continue to unlock the secrets of planetary formation and stellar evolution.
