A team of international astronomers led by Benjamin Thomas of the University of Texas at Austin has used observations from the University’s McDonald’s Observatory’s Hobby-Eberly Telescope (HET) to unravel the mysterious mystery of a stellar explosion discovered years ago and still ongoing.
How Will These Results Help Astronomers?
The results, published in today’s issue of the Astrophysical Journal, will help astronomers better understand the life and death of massive stars.
When an exploding star is first discovered, astronomers around the world begin observing the star with telescopes because the light it emits changes rapidly over time. They see the light from the supernova getting brighter, peaking and then dimming.
The physical properties of a system can be inferred by noting the timing of these light peaks and valleys, called “light curves,” and the characteristic wavelengths of light emitted at different times.
“The really cool thing about this kind of science is that we’re looking at radiation from maternally emitted matter before it explodes into a supernova,” said Thomas. “So, it works like a time machine.”
Read: First Time in History: Red Supergiant Star Exploding in Massive Supernova
What Is Supernova 2014C?
2014C supernova whose ancestor is a binary system, a system in which two stars orbit each other. The more massive stars evolved and expanded faster and lost their outer hydrogen layer as a companion.
The inner core of the first star continued to burn lighter chemical elements into heavier elements until it ran out of fuel. At this time, the external pressure of the core, which was supporting the star’s enormous weight, dropped. The star’s core collapsed, causing a huge explosion.
This creates a type of supernova that astronomers call “Type Ib”. In particular, Type Ib supernovae are characterized by the absence of hydrogen, at least initially, in the ejected matter.
Thomas and his team have been tracking SN 2014C with the McDonald’s Observatory since its discovery that year.
Many other groups around the world have also used telescopes on the ground and in space to study it in different types of light, including ground-based super-array radio waves, infrared and space-based X-rays. Chandra Observatory.
Read more: Will we see a Supernova explosion in 2022?
Why The Observation Of SN 2014C Doesn’t Set With The Picture Of Astronomers Expectations?
However, studies of SN 2014C with all other telescopes did not add a consistent picture of how astronomers think a Type Ib supernova should behave.
First- The optical signature of the Hobby-Eberle telescope (HET) showed that SN 2014C contained hydrogen. This surprising discovery was made independently by other teams using different telescopes.
“It’s completely strange that a Type Ib supernova is starting to show hydrogen,” said Thomas. “There are only a few cases that have been found to be similar.”
Second- The optical brightness (light curve) of this hydrogen behaved strangely.
Most of the light curves (radio, infrared and X-rays) of the SN 2014C followed the expected pattern. That is, it brightens, peaks, and then begins to fall. However, the optical light of hydrogen remained stable.
UT Austin professor and group member J. Craig Wheeler said, “The puzzle we were wrestling with was how do we fit the Texas HET observations of hydrogen and its properties into the [Type Ib] picture?”
Also read: Mysterious Ring Discovered Could Be The First Known Intergalactic Supernova
Model Given By The Scientists To Fit The HET Observations?
The team proposes a model of a binary bulb system in which the hydrogen envelopes of two stars merge to form a “common envelope configuration” contained within the same gas envelope. The pair then ejected this shell into an expanding disk-like structure surrounding the two stars.
When one of the stars exploded, the fast-moving ejecta collided with the slow-moving disk and glided along the surface of the disk with a “boundary layer” at medium speed.
The team hypothesized that this boundary layer was the source of the hydrogen they discovered, and spent seven years working with HET.
HET data thus turns out to be the key to unraveling the mystery of supernova SN 2014C.
“In a broad sense, how massive stars lose mass is a big scientific problem we’ve been solving,” Wheeler said. “What is the mass? Where is she? When was she expelled? What physical process? This was the macro problem we were dealing with, Wheeler said. “And 2014C was a really big event that showcased this process,”
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