But not so fast. Before a star settles into middle age on
the main sequence, it has to shake off some of its, youthful energy, in
particular, more technically what's going on is that the end of.
Collapse is accompanied by these polar outflows that we saw in the case of L1527
and even more directly columnated High velocity jets of material being
ejected from the poles of the star. So along the axis of its rotation.
It turns out that these fulfill a very important part in the mechanism of
collapse of stellar formation itself, because they carry off excess angular
momentum, allowing material to accrete under the star from the protoplanetary
disc. The exact mechanism that governs their
creation is still being nailed down but we can observe them, we can observe them
because this ejected material plows at high speed into the surrounding gas.
Compressing it and heating it and then as a result, the material glows.
These were first discovered and termed, these objects, these regions of hot
glowing gas were termed Herbig-Haro objects.
I don't know how to pronounce either of those names correctly.
But it was later discovered that they were associated with the formation of a
star. So what were considered as two
Herbig-Haro objects turned out in the middle.
To conceal nassin star these can be 50,000, 100,000 astronomical units away
took awhile to make sense of this and It we've been watching these objects for
long enough now that we can actually produce a.
Sequential year, frame a year of movies of their evolution.
Here's the first Herbig-Haro object over eight years and you can see the jet
expanding. Here's another film of another
Herbig-Haro object and what you see here is that there's a structure to this jet
that's being ejected. It's not a smooth jet, there are these
clumps, they're about the size of the solar system to give you a scale.
And these clumps are supposed to be expected to be regions where
The ejector from one. rapid pulse are plowing into ejections
from a previous pulse which tells you that there is a structure to this eject
this process of ejection it's not completely smooth and
What this causes in the vicinity of the star of course, is these huge stellar
winds that we talked about, stars in this phase are low mass stars.
At this phase of their existence are called, T Tauri stars, they exhibit
irregular and rapid variability possibly associated, to, changes in the opacity of
the, Dust and a clouds that still surround them they exhibit huge rates of
mass loss as much as 100 millionth of a solar mass per year and this face can
last for 10,000,000 years this is 1,000,000 times the rate at which the sun
is losing mass to the solar wind currently so the sun in its 10,000,000
year tetori stage lost a lot more mass then it will use throughout its entire
10,000,000,000 year main sequence career and this winds are directed in.
for out from the poles but when I say directed out from the poles you need to
get a scale notice that the scale of this internal cylinder is about astronom a 100
astronomical units so that there is this outward flow in all directions.
Out into the disk, except, at the very surface of the disk, the models as I said
are not quite clear on how to model this. there use to be the prevailing opinion
was at some point, that these waves are generated, the outflow is generated by
the shock wave when the collapse stops, and there's in falling matter colliding
with it. Of course as one would expect with the
bipolar nature it turns out that the stellar magnetic
fields play an important role. These are very violent and dramatic
events. You can see that here in this movie.
That bubble is, approximately 100 billion kilometers across, and it's dramatically
growing. these other stellar types are the higher
mass analogues of T Tauri stars. All star formation is accompanied by this
violent outflow. This is what cleaned out the solar
system. And now, having shaken that off, the sun
is indeed ready to settle in with the.