The aismnw. Stars C and D have the same brightness.from ea (-\tl "Whatwould you need to know to deter-

mine their relative magnitudes?

Answer the following questions on a separate sheet of paper.

4. Explain how astronomers measure the distance to nearby stars. ,..y ";"'\'p"d OJ.4& P"'f("'G\/lG\)( (measul'.'e. now WlU.cn. .5+«r5 apf¥ar. -to move ClCiCfin~+- CI bGl~q,v ','5. "What are the main character"lstlcs used to classify stars? J s+ars that l4rlt- mtJch flJ~rIt siz.e ,-re.mperQ11.Ire elM brjf/fh~ss OlVV().,;6. How' would you classify the sun b'<1sedon each of these characteristics? mt.lS,s, ' 7., n1editAWi Sil£. s+ar, I"w; ~OOO "C very brf~h{- ~ 'h+,erm.edl ateAsmr

.•. Building VocabuRary l -T€mp-too!erd ". 1.1

. .- ';J',fil er~+e :pf"l ~rr:ri€'SSFrom the list below, choose the ,term that best completes each sentence. J!

galaxy universe light-year'parallax giant star apparent magnitudeabsolute magnitude Hertzsprung-Russell diagram main sequence

7. A star's brightness as if it were a standard distance is its Qbso(yte maSf'iitude8. A huge group of stars, such as the Milky 'Nay, is a(n) ~ I0.)('1 .

.9. The unit used to measure distances between stars is a(n) ~n+ -year.10. The region of the Hertzsprung-Russell diagram with the most stars is the

((lain 5e~uence11. A graph of stars showing temperature on the x-axis and brightness on the

y-a..'Cisis a(n) Heftz.spOAYlj -:~Usse.lI cliGt5ram12. Parallax is used to determine the distance to nearby stars.

Characteristics of Stars

Use the following H-R diagram to answer questions 1-3.Write your answers in the spaces provided.

A 1. Which star has the greatest brightness?

2. vVh,ichhas the lowest brightness?

High AS

CO eO

L F.ow~~ ~~ ~~High Temperature Low

13. The \.Anive.rse is all of space and everything in it. ,

14. The brightness of a star as s~en from Earth is its apparent ntt3n J+Uclelh(jJh~.t"S515. Because of its large size, the star Aldebaran is often called a(n)

, jiAA+15fQr !.mt! i'l 5-rar

Lives of Stars

Fill in each blank with the correct letter from the diagram., . ..........~: .: '.. '" ..

" :··':Gas;:,'·,, • :~::. &:',:"•.• : '-, :">,' 04st ", ' • -, ,... '" :.: ..: 3 : : : ..: -, '

.... A'·' ..Time-------------------------------- ~e 1. Red giant or supergiant

8 . 2. Where fusion begins

A 3. Part of a nebula

£ 4. vVhite dwarf, neutron star, or black hole

C S. The stage the sun is in

Fill in the blank.

B

---- ...•) 0c

---1) •

E

Birth of star- )0o

6. How long a star lives and what it becomes at the end of its life dependprimarily on its mass

.• Building Vocabulary

From the list below, choose the term that best matches each phrase.

e 7. pulsar a. exerts s~h a strong gravitationalpull that no electrornag-

C 8. white dwarfnetic radiation can escape

b. a huge cloud of gas or dust in space

b 9. nebula c. what an average-sized star becomes at the end of its life

d d. the earliest stage of a star's life10. protostar e. emits pulses of radio waves

h 11. supernova f. shines brightly in the center of a distant galaxy because of

Sthe friction of material spiraling around it

12. neutron star formed from the leftover material after a giant starg.Q 13. black hole explodes, with three times the mass of the sun, but a diarn-

feter of only about 20 kilometers

14. quasar h. an explosion that occurs at the end of a giant star's life

iagram

GoaD 0 Reinforce your understanding of the Hertzsprung-Russell diagram.

Think Abotllt ItThe Hertzsprung-Russell diagram shows a plot of many stars' temperature against luminosity. Note that thehottest temperatures are to the left. Luminosity is compared to our Sun, which has a luminosity of 1.

1000000

10000

c::::l

C/J

~0.9 100"0(j)

CoQ.

E0ol::-.c:;;0c:'E:::l-l

1100

_1_10000 o B F 6000

A MKG25000 300010000

Temperature (0C)

What to DoAfter studying the diagram, answer the following questions.

Questions1. On the above diagram, locate and label the main sequence, white dwarfs, red giants, and supergiants.

2. Our Sun is a G2 star, about a quarter of the way along the G category. Locate our Sun on the diagram.

3. What colour stars are most numerous?Red stars

Stellar Evolution

Goal • Reinforce your understanding of how stars evolve.

What to DoWhile reading "The Evolution of Stars" on page 468 of SCIENCEPOWERTM 9, answer the following questions.

2.

3. r,

4.

5.

6.

7.

8.

9.

11. "What determines the outcome of a supernova?

-r~ oLJ-COY'vL12.- Df-- u. SU.ptlfLDVa.. 4fendS 6Yl Ik12. Describe the two end results of the cores of massive stars.

14-- 6iJLux M6S IAP~) 3 resLd-is,k 6~r 0 vcr 3 601Cd' fv\.-t.$ us

i ¥f

Stages in the Formationof Star§

GoaR •• Reinforce your understanding of the stages in the formation of stars,

What te DoUsing the list of terms below, complete the following concept map on the formation of a Star.You can use termsmore than once. Write the correct term in each space.

centre O'as increases stableo·compress gravitational roam sequence temperaturedust helium . nebula 10 billionfusion hydrogen pressure 10000000°C

1. D--t <): and crus. J

t t :in a n eblJ. 10.

2. As the cloud begins to .CoNprtsS, the temperature f Il.Crease.-)

3. When the k V'.~(o.lur< in the centre reaches 10 01;I) O1J0 4C.}iell UW\, be~.

4. The increased pres >I,.t.rf... . and the energy production stops the grul/lf-a.·hirta..,! collapse-of the

star. The sur becomes sk,('! e.. and begins to shine brightly.

5. On a Hertzsprung-Russell diagram, the sur is now located on the 1IY761 n ;j4y Ul/l C~I

The Sun -~e.llowI tnfifmediQ+e sm~= H-\'eo/cle --" 10 b,Uiof' '1ears~ "V 4-.Co b,\Hon yeors old

~,

•. Understanding lVila,inI'~;eas

Label the diagram of the sun below.

4. .cn .tJ

-) htdo seen du(i"jan eclipse

• Building Vocabulary

Match each term with its definition by writing the letter of the correct definitionin the right column on the line beside the term in the le~ column. , .

f' a. the layer of the sun s atmosphere that makes light.,. 7. solar flare , b. the layer of the sun's atmosphere that has a r~ci~h~gLCl'tf

~) 8. core c. the layer of the sun's atmosphere that looks like a11,~19during an eclipse

d. areas of gas on the sun that are cooler than the gases, around them

9. chromosphere

__ d..;.... _10. sunspote. reddish loops of gas that l!uk sunspots in pairs or groups

f. explosions that occur when the loops b~~ -sunspotssuddenly connect

g. a stream of p'artides produced by the corona~:;;; .

h. the ~r of the sun

L the joining of h}'drogen atoms to form heliu~- -- .. ~~. ~-.

11. corona---12. nuclear fusion---

__ 0...,;..._ 13. photosphere

e. 15. pro minenC-et

Au. _l(Q.~ - vvnUl sdQ( PQ("-HcAes en+« co("f+,'s atmosphere- AurorQ 13oreQ'i~ -+ Nor-H1e.rn l-tjh-f-s

~yorQ Aus-fra'i5~ Southern L\qtl+-S - ~)

Characteristics of Stars and their lifecycles (Answers)

1. All stars are born in a nebula _2. The force of gravity is the major factor in the

formation of stars.3. A nebula is a huge collection of dust and gas attracted by the

force ofgravity _4. An example of a dark nebula where stars are born is _the Eagle

nebula or pillars of creation _5. There are several characteristics that can be used to describe stars

such as _size or mass_, _temperature and colour , and_brightness or tuminosity _

6. A star can vary in size from very small called _a dwarf , tomid-size called _intermediate mass or main sequence.: _ andmassive called _super giant"---_---:- _

7. The unit used to measure the size of stars is solar mass__The Sun is 1 _solar mass. _

.8. An example of a super massive star is _Bete/eguese or Rigel orAntares, _

9. Astronomers determine the temperature of stars by their_colour . The coolest stars are _red , theirtemperature is about_3500 °C_ and an example would be__ Betelgeuse~ _

1O.Very hot stars are _blue-white in colour. Their temperatureis about 10000 °C_and an example is _Rigel __11. Brightness or _luminosity is another characateristic ofstars. An example of a super bright star is __ Rigel or EtaCarinae, _12. Using these star characteristics, the Sun would be yellow_(colour), _above average in size (1solar mass)_size, _6000_°C, and_above average in brightness.13. A graph plotting the characteristics of stars is called a___ Hertzsprung-Russell diagram.14. Brightness or luminosity is plotted on the Y- axis and

" temperature is plotted on the X- axis.15.The diagonal or S shape region in the centre of the H-R diagram is

called the __ main sequence and this shows starsin the prime of their lives .

.16.ln these stars, the force of Jlravity pushing in equals theforce of nuclear _fusion__ pushing out and so the star is stable.

17. When a nebula grows and the force of gravity attracts more andmore dust and gas, the temperature warms and a-protostar is formed.

18. Eventually, the temperature reaches 10 000 000 °C and nuclear_fusion occurs. A star is born!

is.The length of time a star lives and its fate depends on its_mass. _

20.A small mass star such as a red dwarf has a verylong lifespan, about __ 100billion years becauseit uses its fuel up very slowly.

21. When a red dwarf runs out of fuel it becomes adwarf and then a black _dwarf _

22. An intermediate mass star, like the Sun lives for about_10billion_ years.

23.When it runs out of the fuel, the core will contract and the outerlayers of the star will expand to form a _red giant

while

24. The outer layers of the star will peel away forming a -planetarynebula . Examples of other stars that have already met this fateare _the Hourglass nebula_.,_the cars eyenebula or _thering nebula. _

25. Eventually, the core will become a _ white dwarf whichis found _on the bottom Pi§kt l'eFt- of the H-R diagramand then it will become a __ black dwarf _

26. A massive star such as __ a blue supergiant lives foronly 7 million years. These super massive stars "livefast and die young".

27. When a massive star runs out OF-hydrogenfuel, other elements arefused such as _He_, _C_ ,_81_' _. Eventually, the core containsiron and is extremely unstable, a huge explosion called a_supernova occurs.

28.The end state of such a massive star depends on the size of thecore. A smaller core of 1.4 to 3 solar masses will produce a_neutron star and a larger core of over 3 solar masseswill produce a _black hole. _

29. The most numerous stars are the red dwarfs andthis is because they _havesuch long lifespans. _