- 3975 - TYCHO SUPERNOVA - new discoveries since 1572. NASA’s “Imaging X-ray Polarimetry Explorer” (IXPE) has uncovered new information about the Tycho supernova remnant, an exploded star in the constellation Cassiopeia, the light from which was first seen on Earth in 1572.
------------ 3975 - TYCHO SUPERNOVA - new discoveries since 1572
- The results
offer new clues about how shock waves created by these titanic stellar
explosions accelerate particles to nearly the speed of light, and reveal, for
the first time, the geometry of the magnetic fields close to the supernova’s
blast wave, which forms a boundary around the ejected material, as seen in this
composite image.
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- These
scientists have uncovered new information about the remains of a star whose
explosion was discovered 450 years ago. The results provided new clues about
how the conditions in the shock waves created by titanic stellar explosions,
called supernovae, accelerate particles to near the speed of light.
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- The
supernova remnant is called Tycho, named for Danish astronomer Tycho Brahe, who
noticed the bright glow of this new “star” in the constellation Cassiopeia in
1572. In the new study, astronomers used NASA’s “Imaging X-ray Polarimetry
Explorer” (IXPE) to study polarized X-rays from the Tycho supernova remnant.
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- IXPE
revealed the geometry of the magnetic fields close to the shock wave, which is
still propagating from the initial explosion and forms a boundary around the
ejected material. Understanding the magnetic field geometry allows scientists
to further investigate how particles are accelerated there.
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- Tycho was
observed by humanity in the past, and had a lasting social and even artistic
impact. 450 years after its first appearance
in the sky, we see this object again with new eyes and to learn from it.
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- Measuring
X-ray polarization tells scientists the average direction and ordering of the
magnetic field of light waves that make up X-rays from a high-energy source
like Tycho. The polarized X-rays are produced by electrons moving in the
magnetic field in a process called “synchrotron emission.”
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- The
polarization direction from the X-rays can be mapped back to the direction of
the magnetic fields at the location where the X-rays were generated. This
information helps scientists address some of the biggest questions in
astrophysics, such as how Tycho and other objects accelerate particles closer
to the speed of light than the most powerful particle accelerators on Earth.
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- The process
by which a supernova remnant becomes a giant particle accelerator involves a
delicate dance between order and chaos.
Strong and turbulent magnetic fields are required, but IXPE is showing
us that there is a large-scale uniformity, or coherence, involved as well,
extending right down to the sites where the acceleration is taking place.
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- During its
decades of operation, NASA’s “Chandra X-ray Observatory” has repeatedly
observed the Tycho supernova remnant.
With its ability to identify and track polarized X-ray light, IXPE
builds on the groundwork laid by Chandra. Information from IXPE allows
scientists to better understand the process by which cosmic rays, highly
energetic particles that permeate our galaxy are accelerated by supernova
remnants.
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- IXPE helped
map the shape of Tycho’s magnetic field with unprecedented clarity and scale.
Although previous observatories have looked at Tycho’s magnetic field in radio
waves, IXPE measured the shape of the field on scales smaller than one parsec,
or roughly 3.26 light-years, a vast size in terms of human experience, but the
closest researchers have ever come to observing the source of the highly
energetic “cosmic rays” emitted by one of these distant phenomena. This information
is valuable as scientists explore how particles are accelerated in the wake of
the initial explosion’s blast wave.
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Similarities and surprising differences between IXPE’s findings at Tycho
and at the Cassiopeia A supernova remnant, an earlier subject of study. The
overall directions of the magnetic fields in both supernova remnants appears to
be radial, stretched out along a direction extending outward.
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- But Tycho
yielded a much higher degree of X-ray polarization than Cassiopeia A, suggesting
it may possess a more ordered, less turbulent magnetic field.
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- The Tycho
supernova is classified as a Type Ia, which occurs when a white dwarf star in a
binary system shreds its companion star, capturing some of its mass and
triggering a violent explosion.
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- The
obliteration of the white dwarf sends debris hurtling into space at tremendous
speeds. Such events are commonly believed to be the source of most of the
galactic cosmic rays found in space, including those that continually bombard
Earth’s atmosphere.
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- The Tycho
supernova blast itself released as much energy as the Sun would put out over
the course of 10 billion years. That brilliance rendered the Tycho supernova
visible to the naked eye here on Earth in 1572, when it was spotted by Brahe
and other stargazers, potentially including an 8-year-old William Shakespeare,
who would go on to describe it in an early passage of “Hamlet” at the turn of
the 17th century.
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April 27, 2023 TYCHO SUPERNOVA 3975
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--------------------- --- Thursday, April 27,
2023 ---------------------------
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