- 4171 - WEBB TELESCOPE - sees the most distant galaxies? The power of JWST is finding that things that have been studied for years are now surprising us.
------------- 4171 - WEBB TELESCOPE - sees the most distant galaxies?
- The James Webb Space
Telescope (JWST) is bringing us spectacular images of distant galaxies and
discoveries of dozens of new black holes. Yet JWST is also rewriting
scientists’ understanding of objects on a slightly smaller, more relatable
scale: how planets form from swirls of gas and dust around young stars. Such
‘protoplanetary’ disks are what the environs of the Sun would have been like
4.6 billion years ago, with planets coalescing from the whirling material
around an infant star.
-
- JWST is revealing
how water is delivered to rocky planets taking shape in such disks. It’s
providing clues to the exotic chemistry in these planetary nurseries. And it
has even found fresh evidence for a cosmic hit-and-run in one of the most
famous debris disks, encircling the star Beta Pictoris.
-
- Other telescopes
have probed many of these disks before. Astronomers have taken impressive
pictures of dark gaps etched like grooves in a bright vinyl record, marking
where planets are being born and clearing out gas and dust from the disk. But JWST’s unprecedented vision allows
astronomers to probe these realms in original ways.
-
- New JWST glasses
were use to gaze on the protoplanetary disks of four stars. The scientists
could see that two of the disks contained large amounts of cool water, just
close enough to the star for the water to be liquid rather than frozen.
-
- That observation
supports a theory put forward decades ago, that icy pebbles can drift inwards
from the outer part of the disk until they get warm enough to release their
water into the inner disk. This
reservoir of water can serve as a raw ingredient for planets forming close to
the star.
-
- The protoplanetary
disk surrounding a small star called ”J160532” has a surprisingly large amount
of carbon. A planet taking shape in a disk awash in carbon compounds could draw
on a wide variety of interesting chemistry as it forms. Small stars such as
this one frequently host small rocky planets; if such planets can sweep up
diverse ingredients as they form, the results could be planets that are
mind-bogglingly different from our Solar System’s rocky planets, such as Venus,
Earth and Mars.
-
- Benzene was found
in the disk around J160532 which is the first observation of the molecule in a protoplanetary
disk. Benzene is a carbon-containing ‘organic’ molecule, but its detection
probably does not signal the presence of the ingredients required for life. It
might mean that radiation flooding from the star is destroying dust grains rich
in carbon, releasing benzene into the disk. The disk also contains lots of
other carbon-containing compounds, such as acetylene, and indeed has more
carbon than oxygen overall.
-
- It’s really a
chemistry we’ve never seen before in disks.
Even disks that have probably already formed all their planets are
giving up their secrets to JWST. The
disk around Beta Pictoris, a star that lies 19 parsecs from Earth in 1984
became the first star known to have a debris disk encircling it.
-
- These images have
revealed a filament of dust that astronomers are calling the cat’s tail
stretching out of the debris disk at a quizzical upright angle. The cat’s tail
of Beta Pictoris is probably a stream of dust and other debris that was kicked
out of the star’s disk when large rocky chunks smashed into each other.
-
- We’re seeing the
aftermath of a massive collision in the disk around the bright star Fomalhaut
had also shown clouds and belts of dust expanding outwards, suggesting that
lots more could be going on in the system than anyone had suspected.
-
-
September 27, 2023 4170
------------------------------------------------------------------------------------------
-------- Comments
appreciated and Pass it on to whomever is interested. ---
--- Some reviews are
at: -------------- http://jdetrick.blogspot.com -----
-- email feedback,
corrections, request for copies or Index of all reviews
--- to: ------
jamesdetrick@comcast.net
------ “Jim Detrick” -----------
--------------------- ---
Thursday, September 28, 2023 ---------------------------------
No comments:
Post a Comment