Pablo Martínez-Juarez
WriterEnvironmental economist and science journalist. For a few years, I worked as a researcher on the economics of climate change adaptation. Now I write about that and much more.
NASA’s Hubble Space Telescope has provided scientists with a new image that carries an intriguing story, even if the narrative isn’t immediately visible. It’s a tale of false appearances.
“Picture of the Week.” The Hubble telescope recently captured an image that depicts galaxy UGC 5460. A few years ago, this galaxy experienced what scientists initially thought were two supernovae. However, one of these outbursts may result from a very different phenomenon: a luminous blue variable (LBV).
SN 2011ht and SN 2015as. A few years ago, the galaxy UGC 5460 experienced two major events, which astronomers named SN 2011ht and SN 2015as. These names indicate that both were classified as supernovae (SN) and refer to the years they were discovered: 2011 and 2015.
SN 2015as was classified as a core collapse supernova, a type II supernova that occurs when the core of a massive star–a bigger star than our Sun—runs out of “fuel” for fusion. This depletion causes the core to implode under its own gravity, resulting in a rebound effect.
The outcome is a “cataclysmic explosion,” according to Hubble’s managers. While this is what occurred with SN 2015as, astronomers also have an alternative hypothesis regarding the cause of the SN 2011ht outburst.
Looks can be deceiving. LBVs have the potential to mislead astronomers into mistaking them for a supernova. In fact, they occasionally experience eruptions so powerful that they can be mistaken for supernovae.
However, these outbursts don’t occur at the end of the stars’ lives. Rather, they seem to represent turning points in their evolution. LBVs are enormous, unstable, and relatively rare, which means scientists still don’t understand much about them.
The eruptions of LBVs don’t signify their final explosion. However, astronomers believe that they indicate the stars are in the later stages of their life cycle. As such, these eruptions act as a sort of “last hurrah” before the eventual collapse.
Observing UGC 5460 for clues. This is why SN 2011ht presents a unique opportunity for the Hubble telescope to focus on UGC 5460. The image incorporates four wavelengths of the electromagnetic spectrum. It’ll enable astronomers to learn more about supernovae like SN 2015as and may help unravel the mystery surrounding the outburst observed in 2011. In this process, scientists may also be able to identify the presumed “imposter.”
Image | Jeremy Thomas
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