Class Notes (784,412)
Canada (481,123)
Brock University (11,652)
POLI 1F90 (138)

Monday January 7 Wed Jan 9 Astro 1p02.docx
Monday January 7 Wed Jan 9 Astro 1p02.docx

3 Pages
Unlock Document

Brock University
Political Science
Bozidar Mitrovic

Monday January 7, 2013 Astro 1p02: Star formation: - to find out about the process of star formation one should look at the young stars - mass luminosity relation for main sequence stars is L(luminosity)= M*3.5 (mass of a star) - lifetime of a star = amount of fuel/energy output - M/L = M/M*3.5 = 1/M*2.5 - The youngest stars are located at the top left corner of the main sequence - they appear as bluish (high surface temp.) and they have very high luminosities - The observations show that such stars are surrounded by gas and dust of interstellar material (ISM) - Gas: 74% by mass is hydrogen (H) 24% by mass is helium (He) 2% by mass is all the other elements - dust: consists of core and mantle, 10-100nm across (1nm=10*-9 meters) o core – silicate material o ices of water, ammonia and methane Wednesday January 9 , 2013 - When the clouds of interstellar material are observed in the visible part of the spectrum (wave lengths: 400 nm – 700 nm), they are called nebulae - There are several types of nebulae: o Dark nebula  Starlight is absorbed by the dust particles in the nebula o Reflection nebula (Bluish in colour)  They are bluish for the same reason that the sky appears to be blue on a clear sunny day  Molecules (and dust) in the air scatter blue light more efficiently than the longer wave lengths  Red wave lengths can pass through the molecules where as the blue wave lengths get scattered by the molecules  The stars appears as reddish but the nebula itself is bluish in colour o Emission Nebula (Reddish in colour)  A hot (o-or b-type) star  UV-radiation is intense from a hot star  This process (of electron, UV photon to emitted photon) where a photon of one wavelength is absorbed by an atom and then the atom emits a photon of a different wavelength is called Fluorescence - The stars are formed in a particular type of dark nebula – the Giant Molecular Cloud (example: Eagle Nebula or M16) - Giant – because the
More Less

Related notes for POLI 1F90

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.