reAstrophysics fall trimester  2005 

 syllabus   &  course expectations  &   course links

 Astronomy Picture of the Day        the latest astrophysics discoveries
  what's up in the 
sky this week       Skywatcher's Diary for this month 

November 7
November 8
November 9
November 10
November 11
(always done before class)
brown dwarfs, planets, and superplanets

an updated version of pp.  33-34 on the green book: know the difference between stars, brown dwarfs, and planets

also, see web stuff below: know the types of extrasolar planets and how those planetary systems came to be
brown dwarf leftovers:

what's the difference between stars, BDs, and planets?

how do we find BDs?

why did it take so long?

how do they form?
like stars?
like planets?

stellar old age:

red giants:


what is this electron degeneracy thing?

why does the outer envelope of the star leave
(as a planetary nebula)?
what force pushes it off?

what is a red giant's lifetime?
(relative to m.s. lifetime?)

red giant --> planetary nebula evolution
why does the outer envelope of the star leave
(as a planetary nebula)?
what force pushes it off?

what is a red giant's lifetime?
(relative to m.s. lifetime?)

red giant --> planetary nebula evolution


what are the 5 most important properties of white dwarfs?

web stuff
summary of extrasolar planets properties

 the brown dwarf smoking gun gif


news & discoveries

interstellar sugar provides clue to origin of life


October 31
November 1
November 2
November 3
November 4
jit due by 9:30 am 
(always done before class)
what are the different kind of nebula?
which could lead to star formation in the future?
which indicate that star formation has recently taken place?

the  big question that I will ask you (after we take care of looking at the varioius calculations):
how does a cloud/nebula not in the process of contracting
(which includes the vast majority of clouds in the galaxy) turn into a cloud that is?

if you write down the equation for the total energy of the cloud
(KE + GE), the TWO answers should be apparent
(as they also are if you have done the reading)

and the green book pages 27-31

what changes occur in the appearance of a protostar as it progresses through its various phases?

how do astronomers know how long a protostar spends in various phases?
spend 20 minutes looking at disk and disk/jet observations
(and read the captions!)
on thursday and friday web links below

bring to class, on paper to hand in:

a) name of your nebula type

b) physical conditions:
temperature = ?  (Kelvin)
mass = ?   
(solar masses)
radius = ?  
reference page number from text where you got the above numbers

c) calculate

(1) the kinetic energy of the nebula (in Joules)

(2) the gravitational energy of the nebula (ditto)

(3) the total energy of the nebula (ditto)

(4) conclusion about whether the nebula is expanding or contracting from calculations above

Make sure that your calculation is done in SI units

Check your units!!

bring to class
(on paper that you will hand in):

1) yesterday's assignment

2) determination of the free-fall time of the sun
a) first completing the dimensional analysis problem that we started in class
(and finding tff in terms of G,M,and R)

b) substituting in the relevant numbers and finding the free fall time in years

3) calculating the gravitational lifetime of the sun
(using the physics we did in class yesterday) in years
final project

web stuff
  molecular clouds & cooling

the GMC at the heart Of Orion

Milky Way Molecule Map

Dark Bok Globules in IC 2944

JPL press release on first GMC caught in the act of collapse
( the NY Times article Oct. 10, 1995)


star formation:

star formation propagation
(grav collapse induced by shock wave from O/B stellar winds)

M16 before hubble
 Star-Birth in M16
the Eagle in 2005

shock-wave triggered starbirth
Hubble presents a family portrait of a parent and 6 offspring

star death/supernova:

Cygnus loop shock wave

spiral shock waves in galaxies:

M51 as seen by Hubble 2005

M83's emission nebulae and its spiral arms

  cloud-cloud collisions:

a bow shock near LL Orionis

galaxy collisions
the Antennae:
visible and infrared and x-ray
 how stellar disks form and evolve
(theory in pictures)

the first observations of jets and disks during stellar birth 

stellar Disks and Jets

  12-c-yr long jets

Stellar Disks Set Stage for
Planet Birth in New Hubble Images

disks without jets: planet building?:

5 years ago we had 1; now,  hundreds

the original discovery of proplyds in the

Orion Nebula

Orion Nebula Mosaic and Protoplanetary Disks

protoplanets within disks?:

making protoplanets at beta Pictoris
 photometry lab due
news & discoveries
2 new moons of Pluto?

Glimmer of first stars spied?.... Spitzer Press Release ....
others say "not so fast..."

astronomers on verge of seeing black hole?
 what we saw tonight on the roof:

Andromeda galaxy

Mars &

globular cluster M15


h and
c Persei double cluster

open cluster M38

double star Albireo

astro pages for october2005
astro pages for september2005
astro pages for august 2005