Planetary Nebulae Stellar Evolution Part III Dr. Bill Pezzaglia 1 Updated March 23, 2009

According to CNN the world will end 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….

4 Planetary Nebulae Introduction Discovery Spectra Evolution Summary

II. Discovery Messier’s Catalog Herschel names them 5 II. Discovery Messier’s Catalog Herschel names them Nebular Hypothesis Interpretation

A. Messier Catalog 6 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!

The Summer Triangle Cygnus M57 (1779) The Swan Ring Nebula Lyra 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

(accidentally!) by William Herschel using a 6 inch telescope B. 1781: Uranus Discovered 8 (accidentally!) by William Herschel using a 6 inch telescope

Herschel Classifies Nebulae 9 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 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 1802 Wollastan sees lines in solar spectra 12 1802 Wollastan sees lines in solar spectra 1814 Fraunhofer Labels them A, B, C, D Later measures over 500 lines!

A.2. Solar spectrum 13

A.3. Bright Line Spectra 14 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

B. 1786 Herschel discovers: 16 Draco the Dragon Ursa Major H IV 37 (NGC6543) Cats Eye Nebula Ursa Minor Polaris

B.2 William & Margaret Huggins 17 (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

Tom Lehrer: Elements

B.2 William & Margaret Huggins 19 (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 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 Age of Planetary Nebula 21 IV. Evolution & Age Age of Planetary Nebula Distance to Planetary Nebula Did it explode?

A. Exploded Stars 22 (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 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 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 (1970) Dumbbell has Doppler shift of 0.01% 25 (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 Recall the “parallax triangle” 26 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 First Planetary Nebula Discovered was (a) Ring Nebula (b) Cats Eye Nebula (c) Double Helix Nebula (d) Dumbbell Nebula (e) Orion Nebula

Vega Lyra The Harp

Type: Planetary Nebula Cats Eye Nebula 6 Type: Planetary Nebula Where: DRACO

Type: Planetary Nebula Dumbell Nebula 6 Catalog: M27 Type: Planetary Nebula Where: VULPECULA

Type: Planetary Nebula Double Helix Nebula 6 Type: Planetary Nebula Where: AQUARIUS

Type: Planetary Nebula Hourglass Nebula 6 Type: Planetary Nebula Where: MUSCA

Review 33 First Planetary Nebula was discovered by (a) Huggins (b) Herschel (c) Fraunhofer (d) Messier (e) Kant

Review 34 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

Review 35 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

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 Discovered by Messier (first one M27) Herschel interprets as planetary systems forming

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