- 4321 - SUPERNOVAE
- What is the closest? The closest supernova in the modern era is
examined by the James Webb Telescope. The
first discovery was made in November of 1572 when Tycho Brahe noticed a new
star in the constellation Cassiopeia. It was the first supernova to be observed
in detail by Western astronomers and became known as Tycho’s Supernova.
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------------------- 4321 - SUPERNOVAE - What is the closest?
- Earlier supernovae
had been observed by Chinese and Japanese astronomers, but Tycho’s observations
demonstrated to the Catholic world that the stars were not constant and
unchanging as Aristotle presumed.
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- In 1604, Johannes
Kepler watched a supernova in the constellation Ophiuchus brighten and fade.
There have been no observed supernovae in the Milky Way since then.
-
- More than three
centuries passed. Galileo pointed his first telescopes to the heavens.
Astro-photography revolutionized our view of the heavens, as did radio
astronomy. We launched telescopes into space, landed on the Moon, and sent
robotic probes to the outer solar system. But there were no nearby supernovae
to observe with our clever tools.
-
- Until February
1987, when a supernova appeared in the Large Magellanic Cloud. Known as “SN
1987a”, it reached a maximum apparent magnitude of about “3”. It is the only
naked-eye supernova to occur within the era of modern astronomy.
-
- “SN 1987a” is only
168,000 light-years away. It has been studied over the years by both land-based
and space-based telescopes, and recently the James Webb Space Telescope has
taken a closer look.
-
- Most prominent in
the supernovae image is the bright equatorial ring of ionized gas. This ring
was ejected from the star for thousands of years before it exploded. It’s now
heated by shockwaves from the supernova. The equatorial ring girdles the
hourglass shape of the fainter outer rights that stem from the polar regions of
the star.
-
- These structures
have been observed before by telescopes such as Hubble and Spitzer. But, JWST’s real power is to peer into the
center of SN 1987a. There it reveals a turbulent keyhole structure where clumps
of gas expand into space. Rich chemical interactions have begun to occur in
this region.
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- Even JWST wasn’t
able to observe the ultimate jewel of the supernova, the remnant star.
Supernovae not only cast off new material into interstellar space, they also
trigger the collapse of the star’s core to become a neutron star or black hole.
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- Based on the scale
of SN 1987a, a neutron star should have formed in its center. However, the gas
and dust of the inner keyhole region are too dense for JWST to observe it. How
a neutron star forms, and how it interacts with surrounding gas and dust, is a
mystery.
-
- Tycho’s supernova
was just 8,000 light-years from Earth, and Kepler’s about 20,000 light-years
distant. Unless the star Betelgeuse happens to explode in the near future, SN
1987a is likely the closest new supernova we’ll be able to study for quite some
time.
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-
January 19, 2023
SUPERNOVAE -
What is the closest? 4321
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