- 4204 - MILKY WAY'S VIOLENT PAST? Galactic archaeology reveals Milky Way's neighbor Andromeda has a violent past. Chemical analysis of stars in our galaxy next door has revealed its upbringing was more chaotic than our own galaxy's.
--------------------- 4204 - MILKY WAY'S VIOLENT PAST?
- Astrophysicists
looked at the chemical compositions of stars in Andromeda, which is the closest
large galaxy to our own. The goal was to reconstruct its past. After examining the abundance of elements in
Andromeda and considering the fact this galaxy possesses both planetary
nebulae , gas and dust blown away from dying low-mass stars, and red giant
stars, researchers concluded that it experienced dramatic and forceful
formation.
-
- In fact,
astronomers thinks the creation of the Andromeda galaxy was more turbulent than
the origins of the Milky Way. They theorize that Andromeda initially
experienced a burst of intense star formation that created the galaxy's
foundation, with a secondary period of star birth happening between 2 billion
and 4.5 billion years ago.
-
- Although in many
ways Andromeda is similar to our own Milky Way, it's a similarly-sized, spiral
disc galaxy , new research confirms that its history is far more intense and
dramatic, with bursts of activity forming stars in abundance, and two distinct
eras of star formation.
-
- The idea is the
second starburst period was triggered when the gas-rich Andromeda collided and
merged with another galaxy, also replete with gas, in an event that astronomers
call a "wet merger." The influx of gas in such a merger acts as the
fuel to kick-start yet more bouts of star formation.
-
- Andromeda isn’t
finished clashing with other galaxies.
Scientists have long thought that Andromeda experienced collisions and
mergers with other galaxies in its past, because the positions and motions of
its individual stars, the stars started
out in another galaxy.
-
- By looking at the
chemical compositions of these stars, astronomers found two distinct signatures
in the disc components of Andromeda. One family of stars appeared to have ten
times more oxygen than iron, while the other group appeared to have similar
amounts of both elements. This bit adds a new dimension to the understanding of
this galaxy’s past, revealing more about the nature of the suggested collision
and its effect on Andromeda’s stellar population.
-
- Galactic
archaeology can provide fresh new insights into the history of our
universe. By analyzing the chemical
abundance in different ages of stars in Andromeda, astronomers can bring to
life its history and better understand its origins.
-
- Andromeda likely
has a history of violence and its future
looks to be equally turbulent, with our own galaxy set to become part of its
neighbor’s chaotic existence. This is because the Milky Way and Andromeda are
currently on a collision course, set to slam into each other in around 4.5
billion years. This titanic collision will give both galaxies a severe
makeover, wiping out the distinctive arms of both spiral galaxies.
-
- The stellar
population of the Milky Way and Andromeda, which is currently about 2.5 billion
light years away from us, will not slam into each other but will survive to be
thrown into new orbits around a new galactic center. Our own star, the sun, and
the entire solar system are likely to be pushed away from the new galactic
core, moving toward the outskirts of the resultant new galaxy.
-
- Oxygen is one of
the so-called alpha-elements produced by massive stars. The others are neon,
magnesium, silicon, sulfur, argon, and calcium.
Oxygen and argon have been measured with planetary nebulae, but
Andromeda is so far away that the James Webb Space Telescope (JWST) is required
to measure other elements, including iron.
-
- In coming years,
JWST and ground-based large telescopes will keep looking at Andromeda giving
further weight to the new findings.
-
-
October 30, 2023 MILKY
WAY'S VIOLENT PAST? 4204
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