Lives of Other Stars II

        I went on my evening walk and re-listened to “Live of Other Stars” Podcast. I was especially interested in Mass Loss of stars and one class of star, the Wolf-Rayet, have over 20 solar masses, are very hot, and their stellar winds exceed of 1000 MPH which eject a lot of matter giving it a high rate of Mass Loss. If you remember that large stars, with over five solar masses, Mass Loss plays an important role in determining if the star will become a Neutron star, a Black Hole, or even (some believe) a white dwarf. So there is more to this transition to a Neutron star, a Black Hole, or a white dwarf than I was led to believe. And it isn’t set in stone depending on just how massive a star is.

Lives of Other Stars

        I went for my evening walk re-listening to the lecture on “Lives of Other Stars”. Smaller stars with 0.26 solar masses, our Sun is one solar mass, use convection unlike larger star’s Radiative Transport , and mixes the hydrogen in their atmospheres like a lava lamp which causes these small stars to burn all their hydrogen efficiently into helium and are not hot enough to burn helium (what is called helium flash). Their life span can be over 100 billion years and bypasses the red giant stage and goes right to being a white dwarf with a helium core. Stars one and a half time larger than on solar mass also use convection and smoothly transitions to burn heavier elements. Stars with over five solar masses, depending on Mass Loss, go supernova turning into Neutron Stars or Black Holes. Depending on how large a star determines what elements the star eventually burns, the degenerate gas pressure which holds the core from collapsing, and what element ignites a supernova. Population three stars were the first stars to ever form, with over 250 solar masses, and used proton/proton chain reactions to fuse hydrogen into helium to form the first heavier elements. These stars had a life of a few million years and enriched the early universe with these first heavy elements so that smaller stars could form.

Nebulas

        I went for my evening walk and listened to astronomy lecture on Nebulas. A Nebula is interstellar dust consisting of hydrogen, helium, and other trace elements. Nebulas are formed by dying stars that blow out their atmospheres; from Red Giants or Supernovas. New stars are born in Nebulas. There are two kinds of nebula: reflecting and emission. A Reflecting Nebula reflects light from a nearby bright star, and its color is blue. An Emission Nebula is usually the process of new stars being born within and the light from these stars or protostars excites electrons in atoms of the Nebula to higher energies to emit photons. Emission Nebulas are red in color.

        My friend Kula called to ask about the Leonid Meteor Shower that peaks on the 17th and 18th of this month. I told her that the Moon would probably washout any meteors and the smoke from the fires would be another obstacle. I’m not going to bother with this one but I might go out to take a peak just in case!

Life Cycle of the Sun

        Went on my evening walk and listened to an astronomy lecture about the life cycle of our Sun. To make a long story short it will go through a few phases after it falls off the main sequence five billion years from now; burn most of its hydrogen fuel as its diameter expands to form a Red Giant. Helium replaces hydrogen in the core. Hydrogen still fuses a layer around the core as it condenses and heats up. At 100 million Kelvin helium starts to burn in the core producing carbon and oxygen. While all this is happening the outer layers are being breathed out forming a planetary nebula. When all the helium is turned into carbon, the core collapses down into a White Dwarf with electrons packed tightly together (what is called electron degeneracy). Basically a White Dwarf is a diamond and does not fuse matter but shines under its stored heat.