Galaxies and Stars

Day 2:

Kinds of Stars in Galaxies

Star Temperature & Luminosity

Star Type Temperature Luminosity

• Stellar Nebula 1000 k 10000• Protostar 3000 k 1000• Sun-like Star 5000 k 1• Massive Star 25000 k 100000• Red Giant 3000 k 100000• Variable Stage 10000 k 10000• Planetary Nebula 17000 K .1• White Dwarf 8000 K .001• Black Dwarf 5000 k .001

http://aspire.cosmic-ray.org

10,000

100

1

.001

.00001

25,000K 10,000K 6000K 3000K

The Hertzsprung-Russell Diagrampioneered independently by Elnar Hertzsprung and Henry Norris Russell

plots Luminosity as a function of Temperature

Temperature 273 K =0° C, 32° F and 373 K = 100° C, 212° F.

Lum

inos

ity1

= t

he b

right

ness

of

our

sun

5780K

Local Stars

10,000

100

1

.001

.00001

25,000K 10,000K 6000K 3000K

Temperature 273 K =0° C, 32° F and 373 K = 100° C, 212° F.

Lum

inos

ity1

= t

he b

right

ness

of

our

sun

10,000

100

1

.001

.00001

The Hertzsprung-Russell Diagrampioneered independently by Elnar Hertzsprung and Henry Norris Russell

plots Luminosity as a function of Temperature

Temperature 273 K =0° C, 32° F and 373 K = 100° C, 212° F.

Lum

inos

ity1

= t

he b

right

ness

of

our

sun

Animating the Star Life Cycle

1. What happens the sun over time?

2. Difference between yellow & blue star.

3. Eight yellow & blue stars over time.

4. What happens to 10000 stars over time?

5. Quiz

From Early Atoms to All the Elements

• Difference between elements is number of electrons (protons too).

• Elements are recognized in space by their spectral signature (a function of where their electrons are) Study spectra.

• Hydrogen & Helium created in big bang. How were the rest created?

Cooking Up the Elements

Locating the Elements

Activity

Making Molecules=Storing Energy

Energy is captured in chemical bonds and can be released when the bond is broken.– Covalent– Ionic– Metallic– Hydrogen

Covalent Bonds• Covalent bonding is an

intramolecular form of chemical bonding characterized by the sharing of one or more pairs of electrons between two components, producing a mutual attraction that holds the resultant molecule together. Atoms tend to share electrons in such a way that their outer electron shells are filled. Such bonds are always stronger than the intermolecular hydrogen bond and similar in strength to or stronger than the ionic bond.

Ionic Bonds• • Electron configurations of lithium and fluorine. Lithium has one electron in its

outer shell, held rather loosely because the ionization energy is low. Fluorine carries 7 electrons in its outer shell. When one electron moves from lithium to fluorine, each ion acquires the noble gas configuration. The bonding energy from the electrostatic attraction of the two oppositely-charged ions has a large enough negative value that the overall bonded state energy is lower than the unbonded state

Metallic Bonds• Metallic bonding involves the

delocalized sharing of free electrons among a lattice of metal atoms. Thus, metallic bonds may be compared to molten salts.

• The metallic bond accounts for many physical characteristics of metals, such as strength, malleability, ductility, conduction of heat and electricity, and lustre. See also chemical bond.

• Metallic bonding is the electrostatic attraction between the metal atoms or ions and the delocalised electrons. This is why atoms or layers are allowed to slide past each other, resulting in the characteristic properties of malleability and ductility.

Hydrogen Bonding

• Hydrogen bond is a type of attractive intermolecular force that exists between two partial electric charges of opposite polarity. Although stronger than most other intermolecular forces, the typical hydrogen bond is much weaker than both the ionic bond and the covalent bond.

Where can you make complex molecules?

But which planet has an atmosphere protective enough from radiation?

Which planet has liquid water which to dissolve and catalyze chemical reactions?

Which planet has a moon that creates tides to slosh the water around?

Assignment One: Illustrated Biography of an Element

8.5 x 11 b&w poster

1. Choose a molecule.

2. How was your molecule born?

3. Where does it spend most of its time?

4. What are its favorite molecular partners?

5. What does it spend most of its time doing?

6. Other fun facts

Due Monday, July 17, 11:50 am