This week's questions are about stellar birth.
The answers should all be in Universe, chapter 20 (sections 1-2, 7-8)
the reason I know this is that I have shamelessly stolen the questions from the "review questions" at the end of the chapter
 

1. a) Why is the presence of a red nebula at some location in a galaxy an indication that stellar birth has taken
            place there recently?   connect the dots!

        b) is the presence of a blue reflection nebula an indication of recent star formation?  why or why not?

    2. Suppose that an interstellar cloud somewhere exists in hydrostatic equilibrium; remember that means
                that at every layer in the star, the gravity force inward is balanced by the net gas pressure force outwards.
                In order for this balance to change so that the cloud can collapse  to starhood,
                at least one of two things must happen.

                One of these things could be a drop in the gap pressure force outward.

                Explain in practical terms how a star could reasonably reduce its gas pressure outwards
                the obvious way to do that is to lower the temperature of the interstellar cloud, because
                temperature determines gas pressure (via the perfect gas law)!

         So how does an interstellar cloud manage to cool off in order to become a contracting protostar? 
        (since the generic answer to this question is pretty obvious
        {after all, how does anything cool off?} I need some specificity and details here...

        and note that I'm NOT asking about how an already-formed protostar is cooling off, but about
        how an interstellar cloud that wants to turn into a protostar is cooling down!
        

   3.  Briefly describe (or list) 3 mechanisms that compress the interstellar medium and thus
                trigger star formation.
                (as you know, review question 20(26) says there are 4; you needn't stop at 3, of course.)

I did my own work on this JIT.

Click on the  button to send the results to Kolena

or click   to start over.