- 4602 - MILKY WAY - James Webb latest findings? - James Webb telescope finds 1st possible 'failed stars' beyond the Milky Way. They could reveal new secrets of the early universe. They may have found dozens of elusive brown dwarfs , strange objects larger than planets but smaller than stars, beyond the Milky Way for the first time ever.
----------------- 4602 - MILKY WAY - James Webb latest findings?
- Astronomers zooming in on the young star
cluster “NGC 602” in the nearby Small Magellanic Cloud (SMC) spotted what may
be the first evidence of brown dwarfs ever seen outside the Milky Way.
-
- Brown dwarfs, or "failed stars,"
are peculiar objects that are bigger than the largest planets but not massive
enough to sustain nuclear fusion like stars.
Brown dwarfs seem to form in the same way as stars, they just don't
capture enough mass to become a fully fledged star.
-
- “NGC 602” is a roughly 3 million-year-old
star-forming cluster on the outskirts of the SMC, a satellite galaxy of the
Milky Way that contains roughly 3 billion stars. (Our galaxy, in comparison,
contains an estimated 100 billion to 400 billion stars.) Orbiting about 200,000
light-years from Earth, the SMC is one of the Milky Way's closest intergalactic
neighbors.
-
- Previous observations of NGC 602 taken with
the Hubble Space Telescope revealed that the cluster hosts a population of
young, low-mass stars. Now, thanks to JWST's incredible sensitivity to infrared
light, astronomers have fleshed out the picture of these stellar newborns,
revealing precisely how much mass they have accumulated in their short lives.
-
- The results suggest that 64 stellar objects
within the cluster have masses ranging between 50 and 84 times that of Jupiter.
Brown dwarfs typically weigh between 13 and 75 Jupiter masses, making many of these objects prime candidates
to be the first brown dwarfs spotted beyond our galaxy.
-
- These failed stars appear to have formed in
much the same way as stars like the sun through the collapse of massive clouds
of gas and dust. However, for a collapsed cloud to become a star, it must
continue accumulating mass until it reaches an internal temperature and
pressure high enough to trigger hydrogen fusion at its core combining hydrogen
atoms into helium and releasing energy as light and heat in the process.
-
- Brown dwarfs never acquire enough mass to
sustain permanent fusion, leaving them larger than a planet but smaller and
dimmer than a star. This failure to ignite may be a common outcome in the
universe. Astronomers have discovered
about 3,000 brown dwarfs in the Milky Way but estimate that there may be as
many as 100 billion in our galaxy alone, potentially making them as common as
stars themselves.
-
- Studying this group of extragalactic failed
stars further could help clarify why so many stars seemingly fail to ignite.
But according to the researchers, these oddball objects could also reveal new
insights about the early universe. NGC 602 is a young cluster containing low
abundances of elements heavier than hydrogen and helium, so its composition is
thought to be very similar to that of the ancient universe.
-
- By studying the young metal-poor brown
dwarfs newly discovered in NGC 602, we are getting closer to unlocking the
secrets of how stars and planets formed in the harsh conditions of the early
Universe.
-
- November 7, 2024 MILKY
WAY - James Webb latest findings? 4602
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--------------------- --- Saturday, November 9,
2024
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