Date: November 25th, 2012
Title: Encore: Stars at a Glance
Podcasters: Thomas Hofstätter and Leon Dombroski
Organization: :: The Hidden Space Project ::
This podcast originally aired on August 8, 2011
Description: Stars are like our Sun, but there are many variations of them. One thing is true, they all begin there life by the spark of nuclear fusion at their cores. Almost every dot in the night sky that we see are stars. All of those stars exist within our Milky Way Galaxy. Very rarely will a lone star actually exist in the spaces between galaxies, it is the norm for stars to only exist within galaxies.
Bio: Born in 1993 near Vienna, Austria, Europe. Upper High School with focus on Computer Science.Interested in extreme small and extreme big, devious and uninvestigated things. My main aim is to bring astronomy to public and to establish secular interest in astronomy, physics and mathematics. Host of :: The Hidden Space Project :: at http://hidden-space.at.tf.
If you have any questions, comments or suggestions to the podcast, feel free to write me an email to hidden-space (at) gmx (dot) at or visit me at my website at www.hidden-space.at.tf!
Sponsor:This episode of “365 Days of Astronomy” is sponsored by — NO ONE. Please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this web page, or contact us at firstname.lastname@example.org.
Hello and welcome to this episode of 365 Days of Astronomy. My name is Thomas Hofstätter and I am the host of :: The Hidden Space Project :: at www.hidden-space.at.tf.
[Leon:] And I’m Leon Dombroski from the state of Connecticut in the United States.
[Leon:] Stars are like our Sun, but there are many variations of them. One thing is true, they all begin there life by the spark of nuclear fusion at their cores. Almost every dot in the night sky that we see are stars. All of those stars exist within our Milky Way Galaxy. Very rarely will a lone star actually exist in the spaces between galaxies, it is the norm for stars to only exist within galaxies.
The Lifetime of a normal star looks as follows:
A large star behaves a little bit different:
[Leon:] Open clusters reside mostly within the disk of a galaxy while globular clusters exist outside the galaxy filling a space called the halo. This halo is actually part of the galaxy and it surrounds the entire galaxy. Of course, a star does not have to be in an open or globular cluster but almost always a star will be a part of a galaxy.
But how is a star born? The most abundant material in the Universe is Hydrogen. Clumped together in cold clouds, hydrogen atoms can join together to form molecular hydrogen. This only occurs at extremely low temperatures. These molecular clouds are very difficult to detect because no emission occurs. Much of the interstellar reddening (where a star or galaxy appears more red) occurs because of these molecular clouds. Barnard 68, a dark nebula, for instance is what a molecular cloud “looks” like. Notice the stars are barely visible behind this cloud. However, it is possible to view what’s behind the cloud using an infrared filter.
[Leon:] A cloud has to be “just right” before it can host a future star system. For successful gravitational collapse of a cloud to form a proto-star (a star that has not yet initiated fusion), two criteria must be met:
[Leon:] Smaller clouds within the large cloud can form stars. These molecular cloud fragments also fall under the Jeans criteria, and does affect the overall molecular clouds ability to continue self-gravitation, but that is an advanced topic.
So what can cause a molecular cloud to collapse?
The cloud is collapsing, so now what?
As the molecular contracts under its own gravity, conservation of momentum forces the cloud to take on a disk shape, and it begins to spin. The very center of the cloud remains circular while the outlying gas forms a disk. Material from this disk is ejected perpendicular to to the disk.
A proto-star that is less than 0.8 Solar masses becomes a Brown Dwarf and a proto-star that exceeds 100 Solar masses becomes a Wolf-Rayet star – a very unstable star that cannot hold on to its outer layers.
[Leon:] As the Hydrogen atoms at the core of the proto-star are forced together by heat and pressure, the Coulomb Barrier is reached. The Proton-Proton Chain begins with the fusing of hydrogen atoms into helium atoms – plus some gamma rays, neutrinos and photons.
So what is the equation that demonstrates the energy produced by this reaction? – E=mc2
[Leon:] A T-Tauri star – for instance – is a proto-star that has begun its fusion burning stage – with a bang and a shock wave that blows away any nearby debris close to the star.
Stellar Astrophysics – the study of the stellar process – is not an easy subject, but hopefully this information will bring you one step closer to fully understanding the processes of not only our Sun, but all of the stars in the night sky.
That’s it for today. I hope, you enjoyed it. If you have any questions, comments or suggestions, visit me at my website at www.hidden-space.at.tf.
Thanks for listening and clear-skies!
[Leon:] Good bye for now!
New stories are to come soon!
Text by Ricky Leon Murphy.
Modified by Thomas Hofstaetter.
End of podcast:
365 Days of Astronomy
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