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Stellar Evolution Part III. 1. Planetary Nebulae. Dr. Bill Pezzaglia. Updated March 23, 2009. 2. I. Introduction. According to CNN the world will end Dec 21, 2012. 3. As usual, they got it wrong. The world will end: Dec 21, 5,000,002,012 The sun will…. 4. Planetary Nebulae.

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Planetary nebulae

Stellar Evolution Part III

1

Planetary Nebulae

Dr. Bill Pezzaglia

Updated March 23, 2009


I introduction

2

I. Introduction

According to CNN the world will end

Dec 21, 2012


As usual they got it wrong

3

As usual, they got it wrong

The world will end:

Dec 21,5,000,002,012

The sun will….


Planetary nebulae1

4

Planetary Nebulae

  • Introduction

  • Discovery

  • Spectra

  • Evolution

  • Summary


Ii discovery

5

II. Discovery

  • Messier’s Catalog

  • Herschel names them

  • Nebular Hypothesis Interpretation


A messier catalog

6

A. Messier Catalog

Charles Messier (1730-1817) was hunting for comets. People kept reporting the same fuzzy blobs that were NOT comets, so from 1758-1782 he made a catalog of about 100 of these fuzzy things to “ignore”.

In fact, these 110 objects are nebulae, star clusters and galaxies, which are the best things to look for in an amateur telescope!


Planetary nebulae

The Summer Triangle

Deneb

Cygnus

The Swan

Vega

M57 (1779)

Ring Nebula

In Lyra

1’ in diameter

Made of stars?

Lyra

The Harp

M27: July 12, 1764

Dumbbell Nebula

In Vulpecula

6’ in diameter

Aquila

The Eagle

Altair


B 1781 uranus discovered

8

B. 1781: Uranus Discovered

(accidentally!) by William Herschel using a 6 inch telescope


Herschel classifies nebulae

9

Herschel Classifies Nebulae

  • 1785 Catalog of 1000 objects

  • 1788 another 1000 objects

  • 1802 another 500 objects

  • Classifies objects into star clusters and nebulae. The “types” were:

  • Bright Nebulae

  • Faint Nebulae

  • Very faint Nebulae

  • Planetary Nebulae (Uranus-like in color & shape)

  • Very large Nebulae

  • Very compressed and rich star clusters

  • Compressed clusters of small and large(i.e., faint and bright) stars

  • Coarsely scattered clusters of stars


C nebular hypothesis

10

C. Nebular Hypothesis

  • Herschel (1786) thought that “Planetary Nebulae” might be a cloud of gas coalescing into a star to be surrounded by planets (hence the name)

  • “Nebular Hypothesis” had been theoretically proposed earlier (1734 Swedberg, 1755 Kant)


Iii the message in the light

11

III. The Message in the Light

  • Atomic Spectra Lines

  • Huggins & Nebulium

  • Central Stars are White Dwarfs


A 1 dark line spectra

12

A.1. Dark Line Spectra

  • 1802 Wollastan sees lines in solar spectra

  • 1814 Fraunhofer Labelsthem A, B, C, D

  • Later measures over 500 lines!


A 2 solar spectrum

13

A.2. Solar spectrum


A 3 bright line spectra

14

A.3. Bright Line Spectra

  • 1857 Bunsen’s burner, a clean flame with no color

  • 1859 Kirchhoff suggest using it to study spectra of elements in flame

  • Each element has a unique set of “bright line” (emission) spectra


A 4 kirchhoff s laws

15

A.4. Kirchhoff’s Laws


B 1786 herschel discovers

16

B. 1786 Herschel discovers:

Draco the Dragon

Ursa Major

H IV 37 (NGC6543)

Cats Eye Nebula

Ursa Minor

Polaris


B 2 william margaret huggins

17

B.2 William & Margaret Huggins

  • (1864) Spectra of Cat’s Eye Nebula shows single emission line in green

  • Implies it’s a gas, NOT made of stars (which would have absorption lines)

  • Unknown element “Nebulium” makes greenish color



B 2 william margaret huggins1

19

B.2 William & Margaret Huggins

  • (1864) Spectra of Cat’s Eye Nebula shows single emission line in green

  • Implies it’s a gas, NOT made of stars (which would have absorption lines)

  • Unknown element “Nebulium” makes greenish color

  • (1926) Bowen shows Nebulium is really Oxygen & Nitrogen under extraordinary conditions


C central star white dwarf

20

C. Central Star: White Dwarf!

  • 1800 Friedrich von Hahn discovers central star of Ring Nebula (very faint)

  • Central Stars have Hydrogen, Helium and sometimes Carbon & Oxygen lines.

  • 1918 Wright identifies as type “O” [VERY HOT 125,000 C], hence must be very very small to be so faint!


Iv evolution age

21

IV. Evolution & Age

  • Age of Planetary Nebula

  • Distance to Planetary Nebula

  • Did it explode?


A exploded stars

22

A. Exploded Stars

  • (1956) Iosif Shklovsky proposes that red giant stars explode and form a planetary nebular

  • In 100 years, M27 has expanded 2”

  • Today it is 5’=300” in size

  • How old is it?

  • (300”)(100 yr/2”)= 15,000 years


B 1 doppler effect with sound

23

B.1. Doppler Effect with Sound

1842 Christian Doppler shows “detected” frequency fd depends upon:

  • fs frequency of source

  • v relative speed between detector and source

  • c velocity of sound in medium

  • So if moving 10% speed of sound towards you, the frequency will be increased 10%


B 2 doppler effect with light

22

B.2. Doppler Effect with Light

Amount of shift of color is proportional to speed: v/c = /

A 10% shift in wavelength means 10% speed of light


C 1 size of dumbbell

25

C.1. Size of Dumbbell

  • (1970) Dumbbell has Doppler shift of 0.01%

  • (0.0001)c=(0.0001)(300000km/s)=30 km/sec

  • In 1 year expands:

  • In 15,000 years has expanded to size:

Billion km

15 trillion km(1.5 light year)


C 2 distance to dumbbell

26

C.2. Distance to Dumbbell

  • Recall the “parallax triangle”

  • Hence if the size is 100,000 AU and makes an angle of 300”, how far away is it?

333 parsecs


Review

27

Review

  • First Planetary Nebula Discovered was

  • (a) Ring Nebula

  • (b) Cats Eye Nebula

  • (c) Double Helix Nebula

  • (d) Dumbbell Nebula

  • (e) Orion Nebula


Planetary nebulae

Vega

Lyra

The Harp


Cats eye nebula

6

Cats Eye Nebula

Type: Planetary Nebula

Where: DRACO


Dumbell nebula

6

Dumbell Nebula

Catalog: M27

Type: Planetary Nebula

Where: VULPECULA


Double helix nebula

6

Double Helix Nebula

Type: Planetary Nebula

Where: AQUARIUS


Hourglass nebula

6

Hourglass Nebula

Type: Planetary Nebula

Where: MUSCA


Review1

33

Review

  • First Planetary Nebula was discovered by

  • (a) Huggins

  • (b) Herschel

  • (c) Fraunhofer

  • (d) Messier

  • (e) Kant


Review2

34

Review

  • Age of a planetary nebula is about

  • (a) 100 years

  • (b) 10,000 years

  • (c) 100,000 years

  • (d) 10 Million years

  • (e) 10 Billion years


Review3

35

Review

  • Size of a planetary nebula is about

  • (a) 1 AU

  • (b) 1 km

  • (c) 1 light year

  • (d) 1000x size of sun

  • (e) 1 MPC


Review4

36

Review

4. Planetary Nebula(a) are the disk of material left over from a star formation that will form its planets(b) are made of a close group of stars that are hard to resolve

(c) Are exploded stars

(d) are a nebula that has yet contracted to form a star(e) Are Uranus-like planets


V summary

37

V. Summary

  • Discovered by Messier (first one M27)

  • Herschel interprets as planetary systems forming


Vi references

2

VI References

  • Historial M27 http://www.maa.clell.de/Messier/Mdes/dm027.html

  • Huggins http://www.maa.clell.de/Messier/E/Xtra/Bios/huggins.html

  • History: http://en.wikipedia.org/wiki/Planetary_nebula#Observations