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Stephen C.-Y. Ng McGill University. Outline Why study supernova? What is a supernova? Why does it explode? The aftermaths --- Supernova remnants Will.

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Presentation on theme: "Stephen C.-Y. Ng McGill University. Outline Why study supernova? What is a supernova? Why does it explode? The aftermaths --- Supernova remnants Will."— Presentation transcript:

1 Stephen C.-Y. Ng McGill University

2 Outline Why study supernova? What is a supernova? Why does it explode? The aftermaths --- Supernova remnants Will it destroy the Earth?

3 Where do they come from?

4 Mines?

5 Supernova Explosions!

6 Gold, Silver & More

7 Heavy Elements

8 Building Blocks of Life

9 Life from Exploding Stars! Without supernovae to disperse elements made in stars, no planets, no life!!

10 Why Study Supernova? They are cool most powerful explosions in the Universe J J  1,000,000,000,000,000,000,000,000,000 =

11 Why Study Supernova? They are important produce heavy elements beyond iron, e.g. gold, silver,… recycle materials into space, e.g carbon, oxygen,… shock wave triggers new star formation They can get you a Nobel prize SN Type Ia as standard candles for cosmology They are bombs shock wave physics They are cool most powerful explosions in the Universe

12 What is a Supernova? Nova= new star Naming: SN 2012A, …, SN2012Z, SN 2012aa,… SN 2012ab, …, SN 2012gh Death of a star, most powerful explosions: nuclear bombs brighter than a galaxy (~10 11 stars) more energy than the entire lifetime of a star SN 1994D

13 Historical Classification SN no H H Sino Si He no He Type IaType IbType IcType II

14 Physical Classification Thermonuclear Core Collapse SN no H H Sino Si He no He Type IaType IbType IcType II

15 Why do they explode? Stellar evolution Core collapse Thermonuclear

16 Life of a Sun-like Star Protostars White Dwarf Planetary Nebula Red Giant Sun-like Star Star-Forming Nebula

17 Life of a Massive Star Protostars Black Hole SUPERNOVA Red Supergiant Massive Star Star-Forming Nebula Neutron Star

18 self gravity gas pressure 2,000,000,000 x in 1 second! Pressure Balance

19 Stellar Alchemy

20 Life of a Sun-like Star Protostars White Dwarf Planetary Nebula Red Giant Sun-like Star Star-Forming Nebula

21 Massive Stars

22 Stellar Onion

23 Inert Iron Core

24 Stellar Onion not to scale

25 self gravity gas pressure Core Collapse

26 nuclear force Core Bounce

27 energy: J 99% neutrinos 1% kinetic energy 0.01% visible light produce heavy elements recycle light elements triggers new star formation

28 Compact Core

29

30 How about SN Type Ia?

31 White Dwarf Main Ingredient: White Dwarf

32 Mass Transfer

33 Accreting White Dwarf

34 Binary Merger

35 Standard Candles

36 When can I see a Supernova? Expect 1–2/century in our Galaxy, but long overdue: Cassiopeia A (~1680AD): peak magnitude = 6? too faint to see G (~1868AD): not visible on Earth, too far and obscured

37 SN AD July 4 Crab Nebula (Messier 1)

38 Crab Nebula Remnant of SN1054 Harbors the Crab Pulsar --- most energetic neutron star found in the Milky Way

39 Historical Supernovae Tycho’s SN 1572AD November as bright as Venus visible until 1574 SN AD May 1 brightest SN observed visible for ~18months Kepler’s SN 1604AD October 9 visible in day time for 3 weeks

40 Can I See One Now? Catch one in the act? Go extragalactic! As of today, 6065 extragalactic SNe observed

41 Extragalactic SNe SN 2004et in NGC 6946SN 1994D in NGC 4526

42 SN 1987A

43 1987 Feb 23, in the Large Magellanic Cloud closest (hence brightest) SN observed in 300 yr, since invention of modern telescope ~11 neutrinos detected, 3 hr prior to visible light complex environment Milky Way LMC SMC 168,000 light year

44 Observations Australia Telescope Compact Array Chandra X-ray Observatory OpticalX-rayRadio

45 Evolution

46 Expansion 35,000 km/s 4000 km/s

47 Next Supernova in the Milky Way A major event will be observed by every telescopes in all wavelengths radio, IR, optical, X-ray,  -ray,... Multimessenger astronomy beyond EM radiation neutrino telescopes gravitational wave detectors

48 ~100,000 light years across Artist’s Conception of our Milky Way Galaxy Will it destroy the Earth? location of our solar system Nearest candidate (IK Pegasi): over 150 light years away! Supernova: within 30 light years

49 Summary Supernovae are important: produce everything on Earth Explosion mechanisms: core collapse of massive stars thermonuclear detonations of white dwarfs The next supernova? we are safe

50 SNR G

51 Triple-ring Structure

52 Triple Ring Nebula Morris & Podsiadlowski (2007)


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