Astrophysics falltrimester  2006

 syllabus   &  course expectations

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

October 30
October 31
November 1
November 2
November 3

students return from extended

faculty have countless meetings
 see yesterday's reading


(always done before class)
once you return Monday night, it would be nice if you could spend 15 minutes

matching the steps on page 25 (green book) to

1) those pictured in the
starbirth summary table


2) the figures in Chapter 20 of the text


and pages 172, 177
 see yesterday's reading

the origin of the spiral shock wave in galaxies

things you should know the answer to before coming to class

see above

figures in chapter 20
and pages 172, 177

& those listed on page 25 of green book matched to the 5 starbirth steps ("step 6" could be main sequence stars with, perhaps, planets)
in the starbirth summary table

what two "things" can a non-contracting, non-expanding  interstellar cloud do
(or have done to it) so that its energy (presently zero) can become negative and therefore begin collapsing?
(looking at the terms in the calculation of total energy should immediately tell you!
further hint: if the cloud were an isolated, closed system, its energy would remain the same
(i.e., be conserved) and thus not change its expanding/constracting/sitting still status....
therefore these two "things" must involve an interaction with the outside world)

how in practice do these two "things happen" ?  I want details!
why do starbirth objects end up shaped like disks?

why do they produce jets?

what are the sources of shock waves that squeeze the clouds?

what is the energy source of protostars?

how long do the various phases of starbirth last and how do we know?

see yesterday's questions


what does the H-R diagram of a young cluster (with star birth still going on) look like?

what is the difference between protostars
pre-main-sequence stars?
(behavior?  state of matter? appearance?)

(written assignments
to be turned in)


bring to class
(on paper, ready to hand in at the beginning of class),
a) the name of your "starbirth-related" object

b) its properties
(T, M, R, and composition)
including page number references to text ore elsewhere and/or how they were calculated

c) the kinetic energy

d) the gravitational

e) the total energy

f) whether it is collapsing or expanding & why

g) does the theoretical calculations you did fit expectations?

last chance for corrections to your board presentations on starbirth objects
(there are still some incorrect entries on the board)
web stuff

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

the Antennae, a galaxy-galaxy collision

molecular clouds & cooling

molecules in space

interstellar and circumstellar molecules

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)

Stellar Disks Set Stage for
Planet Birth in New Hubble Images


the original discovery of proplyds in the

Orion Nebula


interstellar sugar provides clue to origin of life

 palomar print
interstellar lab due
news & discoveries
comet Swan visible in evening

 stellar sorting in a globular cluster

HII regions and star clusters in the Antennae

peeling back layers in
Cas A
 dead star creates havoc

Hubble views rare light echo
the amazing Hubble telescope
(NY Times editorial)

Hubble will be fixed
(yes, NASA finally decides in favor of science!)

October 23
October 24
October 25
October 26
October 27
jit due by 8am

we do a lab on interstellar matter;
bring your lab book

(always done before class)
Weighing in on the Neutrino Mass -- the experiment that won  the other half of the 2002 Nobel Prize in Physics


18(8-10) on sunspots



about different kinds of nebulae and their colors and spectra
finish reading chapter 18

check out at least 3 of the web links below
things you should know the answer to before coming to class

what the differences are between an emission nebula, a reflection nebula, a planetary nebula, and a supernova remnant

how is that a portion of the interstellar medium begins its journey toward starhood? to help answer this:

before the collapse begins, what two forces are in balance?

what property (or properties) of the  nebula (protostar-to-be) must change (and how?) so the collapse of the nebula can begin?

what are the  (generic) names of the various kinds of clouds or nebulas that show signs of incipient or recent

answers are all in the reading!

(written assignments
to be turned in)

web stuff
the first neutrino image of the sun

Sudbury Neutrino Observatory
detection  physics

the active sun in the ultraviolet

close-up of magnetic coronal loops

the magnetic corona

a typical coronal hole

hear the sun quake

see what helioseismology tells us

see the sun quake

the most amazing coronal mass ejection
(plus see a comet swallowed)

Seething Sunspot

the solar magnetic carpet

sunspot loops in the UV

CMEs on the active sun


of the week

what the space shuttle has done to science funding in the US


October 16
October 17
October 18
October 19
October 20
(always done before class)
in the sun:
on earth:

boiling water:
p. 188

in the oceans:
p. 188

in the atmosphere:
p. 187-188,
202, 250

in the mantle:
 p. 194-195

and pages 407-408

the neutrino section

the Mystery of the Missing Neutrinos  -- this experiment won half of the 2004 Nobel Prize in Physics

things you should know the answer to before coming to class

how did the temperature get to be so high at the center of the sun so that fusion could start?

 why doesn't the sun collapse under its own gravity?

why does the gas pessure increase with depth in the sun?

why does the gas temperature increase with depth in the sun?

how does the energy released in fusion get to the surface?
by what processes?

why does
the sun switch from photon diffusion to convection about 70% of the way to the surface?

what kind of problem would we do to find the time it takes for convection to move the energy through the outer 30% of the sun?

why does convection occur in boiling water on the stove?
why doesn't photon diffusion work? why not conduction?

how do we detect neutrinos?
what are the various ways?

why does the neutrino interact weakly with matter?

have we solved the problem of the sun's missing neutrinos?
be able to talk sensibly about the different ways of detecting neutrinos

how did we figure out that neutrinos made in the atmosphere were decaying (changing into something else) before they got to the ground
(second reading above)?

how did the affair of the atmospheric neutrinos (second reading above) help us with the first issue
(the missing solar neutrinos, first reading above)?

what was special about the sudbury detector (with heavy water) that allowed it to nail down the solution to the missing solar neutrinos?

(written assignments
to be turned in)

for your nuclear reaction:

write the reaction and balance the three quantum numbers, Q, B, Le

find the energy released in Mev
(make sure that
you start with
Ei = Ef, and no numbers until the end)

find the efficiency of your reaction

find out how long the sun would last (in years) if the sun's core were made completely of the initial reactants of your reaction

find the average acceleration of a convective cell

we derived this in class; you have to find/justify the numerical value

also find the time it takes the cell to reach the surface and the velocity it has when it gets there

web stuff
 first image of an extrasolar planet

statistics of exoplanets

jk's summary of extrasolar planets properties

brown dwarfs, planets, and superplanets

chart of the nucleides
(properties, including mass of atoms.... just type in the box, for example to find the mass of the C12 atom, type C12)

news & discoveries
Hubble finds 16 new planets far across the galaxy

weather on an extrasolar planet


October 9
October 10
October 11
October 12
October 13

make sure that you have your green book and the particle physics handout with you today

jit due by 8 am

(always done before class)


read the captions on green book, p. 14, so you know the evidence for Nemesis, the sun's binary companion

big bang day:
in honor of the Nobel prize award this year,
I will answer questions about the
3 K background radiation and its importance if you have them
(if not, we'll just go onto the next topic)
from the reading
(also, see web stuff below)
18(1) on the fusion going on inside the sun
read about nuclear physics in Walker:

32(1, 4)
Walker 32(6)

a short section on fusion

but block D hasn't covered binding energy yet
things you should know the answer to before coming to class
other ways to detect dark matter besides the rotation curves of spiral galaxies

see mass/inventory of universe link below
find the power law that relates luminosity to mass, using
figure 19-20

what things are in the nucleus?, what things feel the nuclear force? what is the range of the strong force? is there a formula for the magnitude of the force? how big is a nucleus?  how big is a proton? are the protons/neutrons touching? why are some nuclei stable and some not? what is binding energy?

what physics principle was used to calculate binding energy of tritium?

what physics principle was used to calculate the energy released during fusion?

bring an example of a bound gravitational system, a bound electrical system, and a bound nuclear system to class.... maybe you even know the binding energies of each?

(written assignments
to be turned in)

make a table summarizing the results of friday:


1: orbital speed  dependence on r
(e.g., linear, constant, etc)

2: where that dependence  occurs in the galaxy
(near center, near edge, most of galaxy)

3:  mass inside dependence on r

4: shape of  mass distribution
(e.g., spherical, with uniform density, ...)
5 pm homework:

for your planet
(and using ONLY the observable quantities:
period, radial velocity plot,
and spectral/luminosity
class of the star))

1) attach a printed copy of your planet's star's radial velocity curve

2) find the lower limit to your planet's mass

3) % difference between your value and the accepted
(it should be less than 2% unless your orbit is noticeably elliptical)

d) the planet's orbit size

e) % diff

f) a range for the planet's surface temperature (using a reasonable range for albedo)

g) the likely composition of your planet based on its formation temperature
(with justification!)

web stuff
mass/energy inventory of the universe

first image of an extrasolar planet

are periodic extinctions 
  statistically real?  a Scientific American debate

Hubble finds 16 new planets far across the galaxy


RW Mon lab due RW Mon lab due
of the week

Nobel prize cosmology for beginners

Nobel prize cosmology for astronomers-to-be


October 2
October 3
October 4
October 5
October 6
 jit due by 8 am
(always done before class)


8(6) on finding planets around other stars

24(3) on finidng black holes in binary systems
 25(1-3) can be read quickly
(basic stuff about what's our galaxy and how we figured out that we live in a galaxy)

the key sections are 25(4) and box 25-2

we still have to discuss the galaxy's rotation and dark matter
things you should know the answer to before coming to class know the different types of binary stars and how to detect them

how to determine the mass of a galaxy

why/how the shape of the rotation curve -- figure 25-16, page 566 -- tells us that the galaxy contains dark matter

how to tell the difference between a main sequence  star, a giant star,
and a supergiant star

(written assignments
to be turned in)

bring to class:

from the physics equations we had in class today
(N's version of K's 3rd law, with special units; the center of mass condition,
the formula for speed in a circular orbit),
show that

mB3/(mA+mB)2 = PvA3/(8p)3

hint: start with N's version of K3 and then eliminate aB
  using the seesaw condition; then eliminate aA in favor of vA for star A

bring to class:

a printed copy of your planet's star's
radial velocity curve

see the catalogs below
bring to class:

1) your grade record (4 homework scores and 2 lab scores)

2) RE-DO the calculation for the mass of the galaxy in box 25-2, EXCEPT you do it for the mass inside distance d (in kiloparsecs)
where d (in kpc) = 0.7 x (number that the first letter of your last name is in the order of the alphabet).... e.g., if my last name
is Kolena, the first letter of my last nameis K; K is the 11th letter of the alphabet, so I would find the mass inside the distance d = .7 x 11 kiloparsecs
= 7,700 pc...
you will of course need the orbit speed that goes with that distance
from the graph on page 566

3) block D only:
how your knew the units of G in the special units
(not just the answer please)

web stuff
the spectroscopic binary applet

the eclipsing binary applet 
Nobel prize cosmology for beginners

Nobel prize cosmology for astronomers-to-be
Princeton catalog of extrasolar planets

France catalog of extrasolar planets
news & discoveries

   september pages for astro 06