Real Life Death Stars: Measuring Rocks on Alien Planets by Tearing Them Apart

Outreach talk, 40 min. January 2016: Astronomy Days, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.

Transcript

1. Real-Life Death Stars: Measuring Rocks on Alien Planets by Tearing Them Apart JJ Hermes Hubble Fellow University of North Carolina at Chapel Hill jjhermes.web.unc.edu
2. Kitt Peak National Observatory, Arizona
3. My History: The University of Texas at Austin • Undergrad in Physics & Astronomy, 2002-2007 • Ph.D. in Astronomy, 2008-2013 • I have spent >220 nights at McDonald Observatory
4. My History: The University of Warwick • I did my first Postdoctoral Research Fellowship in England – There I learned to include a ‘u’ in words like colour • Astronomers tend to have postdoc appointments for 2-7(!) years before settling in at a faculty job teaching at a university William Herschel Telescope, Canary Islands, Spain
5. My History: The University of North Carolina • Currently I am a Hubble Fellow at the University of North Carolina at Chapel Hill, another postdoctoral research job
6. V = 13.3 mag Star Wars: A New Hope © Disney
7. We Have Found Thousands of Planets Outside Our Solar System
8. “So What Might Alien Life Look Like?” “The Search for Life Beyond Earth…”
9. This is still the stuff of science fiction JD Hancock
10. “What Are Rocks Like on Alien Worlds?” Alien World = Extrasolar Planets (Planets Outside Our Solar System)
11. They are mostly composed of: Iron, Oxygen, Silicon, Magnesium … and Water! Alien Worlds are Just Like Rocks on Earth Earth “Alien Rocks”
12. “So How Do We Know Anything About Alien Rocks?”
13. Light Is the Only Way Know About Anything Outside Our Solar System
14. You Need to Know Two Things: 1. Each Atom Has Its Own Fingerprint 2. Very Old Stars are a Blank Canvas Henry Bloomfield
15. Each Atom Has Its Own Fingerprint Passing SunlightThrough a Prism: Each Line is from an ELEMENT! Boston University
16. La-Lu 57-71 Ac-Lr 89-103 Tc Lr Pm Np Pu Am Cm Bk Cf Es Fm Md No Bh Rf Db Sg Hs Mt 1 2 3 4 5 6 7 1.0079 1 4.0026 2 20.180 10 14.007 7 39.948 18 35.453 17 18.998 9 15.999 8 83.798 36 131.29 54 (222) 86 12.011 6 C 10.811 B 5 26.982 Al 13 28.086 Si 14 30.974 P 15 32.065 S 16 6.941 Li 3 9.0122 Be 4 22.990 Na 11 24.305 Mg 12 39.098 K 19 40.078 Ca 20 44.956 Sc 21 47.867 Ti 22 50.942 V 23 51.996 Cr 24 54.938 Mn 25 55.845 Fe 26 58.933 Co 27 58.693 Ni 28 63.546 Cu 29 65.38 Zn 30 69.723 Ga 31 72.64 Ge 32 74.922 As 33 78.96 Se 34 79.904 35 85.468 Rb 37 87.62 Sr 38 88.906 Y 39 91.224 Zr 40 92.906 Nb 41 95.96 Mo 42 132.91 Cs 55 137.33 Ba 56 138.91 La 57 178.49 Hf 72 180.95 Ta 73 183.84 W 74 (223) Fr 87 (226) Ra 88 (227) Ac 89 (98) 43 126.90 I 53 101.07 Ru 44 102.91 Rh 45 106.42 Pd 46 107.87 Ag 47 112.41 Cd 48 186.21 Re 75 190.23 Os 76 192.22 Ir 77 195.08 Pt 78 196.97 Au 79 200.59 Hg 80 204.38 Tl 81 207.2 Pb 82 208.98 Bi 83 (209) Po 84 (210) At 85 114.82 In 49 118.71 Sn 50 121.76 Sb 51 127.60 Te 52 H He Ne N Ar Cl F O Kr Xe Rn Br IA IIA IIIB IVB VB VIB VIIB IB IIB IVA VA VIA VIIA VIIIB VIIIA 1 5 4 2 3 13 14 15 16 17 18 6 7 8 9 10 11 12 IIIA 174.97 Lu 71 140.12 Ce 58 232.04 Th 90 231.04 Pa 91 238.03 U 92 140.91 Pr 59 144.24 Nd 60 (262) 103 (145) 61 (237) 93 (244) 94 (243) 95 (247) 96 (247) 97 (251) 98 (252) 99 (257) 100 (258) 101 (259) 102 150.36 Sm 62 151.96 Eu 63 157.25 Gd 64 158.93 Tb 65 162.50 Dy 66 164.93 Ho 67 167.26 Er 68 168.93 Tm 69 173.05 Yb 70 (2 ) 72 107 (26 ) 7 104 (26 ) 8 105 (2 ) 71 106 (277) 108 (2 ) 76 109 (2 1) 8 Ds 110 (2 ) 80 Rg 111 10.811 B 5 13 IIIA (2 ) 85 Cn 112 118 113 114 115 116 117 ( ) . . . ( ) . . . (2 ) 87 ( ) . . . (2 ) 91 ( ) . . . Uut Fl Uup Lv Uus Uuo Copyright Eni G © 2012 eneralić HYDROGEN HELIUM NEON NITROGEN ARGON CHLORINE FLUORINE OXYGEN KRYPTON XENON RADON CARBON BORON ALUMINIUM SILICON PHOSPHORUS SULPHUR LITHIUM BERYLLIUM SODIUM MAGNESIUM POTASSIUM CALCIUM SCANDIUM TITANIUM VANADIUM CHROMIUM MANGANESE COBALT NICKEL COPPER ZINC GALLIUM GERMANIUM ARSENIC SELENIUM BROMINE RUBIDIUM STRONTIUM YTTRIUM ZIRCONIUM NIOBIUM MOLYBDENUM CAESIUM BARIUM LANTHANUM HAFNIUM TANTALUM TUNGSTEN FRANCIUM RADIUM ACTINIUM TECHNETIUM IODINE RUTHENIUM RHODIUM PALLADIUM SILVER CADMIUM RHENIUM OSMIUM IRIDIUM PLATINUM GOLD THALLIUM LEAD BISMUTH POLONIUM ASTATINE INDIUM TIN ANTIMONY TELLURIUM PERIOD GROUP IRON MERCURY LUTETIUM CERIUM THORIUM PROTACTINIUM URANIUM PRASEODYMIUM NEODYMIUM LAWRENCIUM PROMETHIUM NEPTUNIUM PLUTONIUM AMERICIUM CURIUM BERKELIUM CALIFORNIUM EINSTEINIUM FERMIUM MENDELEVIUM NOBELIUM SAMARIUM EUROPIUM GADOLINIUM TERBIUM DYSPROSIUM HOLMIUM ERBIUM THULIUM YTTERBIUM BOHRIUM RUTHERFORDIUM DUBNIUM SEABORGIUM HASSIUM MEITNERIUM BORON ATOMIC NUMBER ELEMENT NAME SYMBOL RELATIVE ATOMIC MASS (1) GROUP NUMBERS CHEMICAL ABSTRACT SERVICE (1986) GROUP NUMBERS IUPAC RECOMMENDATION (1985) Lanthanide Actinide ROENTGENIUM PERIODIC TABLE OF THE ELEMENTS LANTHANIDE ACTINIDE DARMSTADTIUM h .com ttp://www.periodni COPERNICIUM UNUNTRIUM FLEROVIUM UNUNPENTIUM LIVERMORIUM UNUNSEPTIUM UNUNOCTIUM Relative atomic masses are expressed with five significant figures. For elements that have no stable nuclides, the value enclosed in brackets indicates the mass number of the longest-lived isotope of the element. However three such elements (Th, Pa and U) do have a characteristic terrestrial isotopic composition, and for these an atomic weight is tabulated. (1) Pure Appl. Chem., , No. , (200 ) 81 11 2131-2156 9 Hydrogen
17. La-Lu 57-71 Ac-Lr 89-103 Tc Lr Pm Np Pu Am Cm Bk Cf Es Fm Md No Bh Rf Db Sg Hs Mt 1 2 3 4 5 6 7 1.0079 1 4.0026 2 20.180 10 14.007 7 39.948 18 35.453 17 18.998 9 15.999 8 83.798 36 131.29 54 (222) 86 12.011 6 C 10.811 B 5 26.982 Al 13 28.086 Si 14 30.974 P 15 32.065 S 16 6.941 Li 3 9.0122 Be 4 22.990 Na 11 24.305 Mg 12 39.098 K 19 40.078 Ca 20 44.956 Sc 21 47.867 Ti 22 50.942 V 23 51.996 Cr 24 54.938 Mn 25 55.845 Fe 26 58.933 Co 27 58.693 Ni 28 63.546 Cu 29 65.38 Zn 30 69.723 Ga 31 72.64 Ge 32 74.922 As 33 78.96 Se 34 79.904 35 85.468 Rb 37 87.62 Sr 38 88.906 Y 39 91.224 Zr 40 92.906 Nb 41 95.96 Mo 42 132.91 Cs 55 137.33 Ba 56 138.91 La 57 178.49 Hf 72 180.95 Ta 73 183.84 W 74 (223) Fr 87 (226) Ra 88 (227) Ac 89 (98) 43 126.90 I 53 101.07 Ru 44 102.91 Rh 45 106.42 Pd 46 107.87 Ag 47 112.41 Cd 48 186.21 Re 75 190.23 Os 76 192.22 Ir 77 195.08 Pt 78 196.97 Au 79 200.59 Hg 80 204.38 Tl 81 207.2 Pb 82 208.98 Bi 83 (209) Po 84 (210) At 85 114.82 In 49 118.71 Sn 50 121.76 Sb 51 127.60 Te 52 H He Ne N Ar Cl F O Kr Xe Rn Br IA IIA IIIB IVB VB VIB VIIB IB IIB IVA VA VIA VIIA VIIIB VIIIA 1 5 4 2 3 13 14 15 16 17 18 6 7 8 9 10 11 12 IIIA 174.97 Lu 71 140.12 Ce 58 232.04 Th 90 231.04 Pa 91 238.03 U 92 140.91 Pr 59 144.24 Nd 60 (262) 103 (145) 61 (237) 93 (244) 94 (243) 95 (247) 96 (247) 97 (251) 98 (252) 99 (257) 100 (258) 101 (259) 102 150.36 Sm 62 151.96 Eu 63 157.25 Gd 64 158.93 Tb 65 162.50 Dy 66 164.93 Ho 67 167.26 Er 68 168.93 Tm 69 173.05 Yb 70 (2 ) 72 107 (26 ) 7 104 (26 ) 8 105 (2 ) 71 106 (277) 108 (2 ) 76 109 (2 1) 8 Ds 110 (2 ) 80 Rg 111 10.811 B 5 13 IIIA (2 ) 85 Cn 112 118 113 114 115 116 117 ( ) . . . ( ) . . . (2 ) 87 ( ) . . . (2 ) 91 ( ) . . . Uut Fl Uup Lv Uus Uuo Copyright Eni G © 2012 eneralić HYDROGEN HELIUM NEON NITROGEN ARGON CHLORINE FLUORINE OXYGEN KRYPTON XENON RADON CARBON BORON ALUMINIUM SILICON PHOSPHORUS SULPHUR LITHIUM BERYLLIUM SODIUM MAGNESIUM POTASSIUM CALCIUM SCANDIUM TITANIUM VANADIUM CHROMIUM MANGANESE COBALT NICKEL COPPER ZINC GALLIUM GERMANIUM ARSENIC SELENIUM BROMINE RUBIDIUM STRONTIUM YTTRIUM ZIRCONIUM NIOBIUM MOLYBDENUM CAESIUM BARIUM LANTHANUM HAFNIUM TANTALUM TUNGSTEN FRANCIUM RADIUM ACTINIUM TECHNETIUM IODINE RUTHENIUM RHODIUM PALLADIUM SILVER CADMIUM RHENIUM OSMIUM IRIDIUM PLATINUM GOLD THALLIUM LEAD BISMUTH POLONIUM ASTATINE INDIUM TIN ANTIMONY TELLURIUM PERIOD GROUP IRON MERCURY LUTETIUM CERIUM THORIUM PROTACTINIUM URANIUM PRASEODYMIUM NEODYMIUM LAWRENCIUM PROMETHIUM NEPTUNIUM PLUTONIUM AMERICIUM CURIUM BERKELIUM CALIFORNIUM EINSTEINIUM FERMIUM MENDELEVIUM NOBELIUM SAMARIUM EUROPIUM GADOLINIUM TERBIUM DYSPROSIUM HOLMIUM ERBIUM THULIUM YTTERBIUM BOHRIUM RUTHERFORDIUM DUBNIUM SEABORGIUM HASSIUM MEITNERIUM BORON ATOMIC NUMBER ELEMENT NAME SYMBOL RELATIVE ATOMIC MASS (1) GROUP NUMBERS CHEMICAL ABSTRACT SERVICE (1986) GROUP NUMBERS IUPAC RECOMMENDATION (1985) Lanthanide Actinide ROENTGENIUM PERIODIC TABLE OF THE ELEMENTS LANTHANIDE ACTINIDE DARMSTADTIUM h .com ttp://www.periodni COPERNICIUM UNUNTRIUM FLEROVIUM UNUNPENTIUM LIVERMORIUM UNUNSEPTIUM UNUNOCTIUM Relative atomic masses are expressed with five significant figures. For elements that have no stable nuclides, the value enclosed in brackets indicates the mass number of the longest-lived isotope of the element. However three such elements (Th, Pa and U) do have a characteristic terrestrial isotopic composition, and for these an atomic weight is tabulated. (1) Pure Appl. Chem., , No. , (200 ) 81 11 2131-2156 9 Helium
18. La-Lu 57-71 Ac-Lr 89-103 Tc Lr Pm Np Pu Am Cm Bk Cf Es Fm Md No Bh Rf Db Sg Hs Mt 1 2 3 4 5 6 7 1.0079 1 4.0026 2 20.180 10 14.007 7 39.948 18 35.453 17 18.998 9 15.999 8 83.798 36 131.29 54 (222) 86 12.011 6 C 10.811 B 5 26.982 Al 13 28.086 Si 14 30.974 P 15 32.065 S 16 6.941 Li 3 9.0122 Be 4 22.990 Na 11 24.305 Mg 12 39.098 K 19 40.078 Ca 20 44.956 Sc 21 47.867 Ti 22 50.942 V 23 51.996 Cr 24 54.938 Mn 25 55.845 Fe 26 58.933 Co 27 58.693 Ni 28 63.546 Cu 29 65.38 Zn 30 69.723 Ga 31 72.64 Ge 32 74.922 As 33 78.96 Se 34 79.904 35 85.468 Rb 37 87.62 Sr 38 88.906 Y 39 91.224 Zr 40 92.906 Nb 41 95.96 Mo 42 132.91 Cs 55 137.33 Ba 56 138.91 La 57 178.49 Hf 72 180.95 Ta 73 183.84 W 74 (223) Fr 87 (226) Ra 88 (227) Ac 89 (98) 43 126.90 I 53 101.07 Ru 44 102.91 Rh 45 106.42 Pd 46 107.87 Ag 47 112.41 Cd 48 186.21 Re 75 190.23 Os 76 192.22 Ir 77 195.08 Pt 78 196.97 Au 79 200.59 Hg 80 204.38 Tl 81 207.2 Pb 82 208.98 Bi 83 (209) Po 84 (210) At 85 114.82 In 49 118.71 Sn 50 121.76 Sb 51 127.60 Te 52 H He Ne N Ar Cl F O Kr Xe Rn Br IA IIA IIIB IVB VB VIB VIIB IB IIB IVA VA VIA VIIA VIIIB VIIIA 1 5 4 2 3 13 14 15 16 17 18 6 7 8 9 10 11 12 IIIA 174.97 Lu 71 140.12 Ce 58 232.04 Th 90 231.04 Pa 91 238.03 U 92 140.91 Pr 59 144.24 Nd 60 (262) 103 (145) 61 (237) 93 (244) 94 (243) 95 (247) 96 (247) 97 (251) 98 (252) 99 (257) 100 (258) 101 (259) 102 150.36 Sm 62 151.96 Eu 63 157.25 Gd 64 158.93 Tb 65 162.50 Dy 66 164.93 Ho 67 167.26 Er 68 168.93 Tm 69 173.05 Yb 70 (2 ) 72 107 (26 ) 7 104 (26 ) 8 105 (2 ) 71 106 (277) 108 (2 ) 76 109 (2 1) 8 Ds 110 (2 ) 80 Rg 111 10.811 B 5 13 IIIA (2 ) 85 Cn 112 118 113 114 115 116 117 ( ) . . . ( ) . . . (2 ) 87 ( ) . . . (2 ) 91 ( ) . . . Uut Fl Uup Lv Uus Uuo Copyright Eni G © 2012 eneralić HYDROGEN HELIUM NEON NITROGEN ARGON CHLORINE FLUORINE OXYGEN KRYPTON XENON RADON CARBON BORON ALUMINIUM SILICON PHOSPHORUS SULPHUR LITHIUM BERYLLIUM SODIUM MAGNESIUM POTASSIUM CALCIUM SCANDIUM TITANIUM VANADIUM CHROMIUM MANGANESE COBALT NICKEL COPPER ZINC GALLIUM GERMANIUM ARSENIC SELENIUM BROMINE RUBIDIUM STRONTIUM YTTRIUM ZIRCONIUM NIOBIUM MOLYBDENUM CAESIUM BARIUM LANTHANUM HAFNIUM TANTALUM TUNGSTEN FRANCIUM RADIUM ACTINIUM TECHNETIUM IODINE RUTHENIUM RHODIUM PALLADIUM SILVER CADMIUM RHENIUM OSMIUM IRIDIUM PLATINUM GOLD THALLIUM LEAD BISMUTH POLONIUM ASTATINE INDIUM TIN ANTIMONY TELLURIUM PERIOD GROUP IRON MERCURY LUTETIUM CERIUM THORIUM PROTACTINIUM URANIUM PRASEODYMIUM NEODYMIUM LAWRENCIUM PROMETHIUM NEPTUNIUM PLUTONIUM AMERICIUM CURIUM BERKELIUM CALIFORNIUM EINSTEINIUM FERMIUM MENDELEVIUM NOBELIUM SAMARIUM EUROPIUM GADOLINIUM TERBIUM DYSPROSIUM HOLMIUM ERBIUM THULIUM YTTERBIUM BOHRIUM RUTHERFORDIUM DUBNIUM SEABORGIUM HASSIUM MEITNERIUM BORON ATOMIC NUMBER ELEMENT NAME SYMBOL RELATIVE ATOMIC MASS (1) GROUP NUMBERS CHEMICAL ABSTRACT SERVICE (1986) GROUP NUMBERS IUPAC RECOMMENDATION (1985) Lanthanide Actinide ROENTGENIUM PERIODIC TABLE OF THE ELEMENTS LANTHANIDE ACTINIDE DARMSTADTIUM h .com ttp://www.periodni COPERNICIUM UNUNTRIUM FLEROVIUM UNUNPENTIUM LIVERMORIUM UNUNSEPTIUM UNUNOCTIUM Relative atomic masses are expressed with five significant figures. For elements that have no stable nuclides, the value enclosed in brackets indicates the mass number of the longest-lived isotope of the element. However three such elements (Th, Pa and U) do have a characteristic terrestrial isotopic composition, and for these an atomic weight is tabulated. (1) Pure Appl. Chem., , No. , (200 ) 81 11 2131-2156 9 Sodium
19. V = 13.3 mag Alwyn Ladell
20. This is Called “Spectroscopy” Passing SunlightThrough a Prism: This dark line here is from CALCIUM Boston University
21. You Need to Know Two Things: 1. Each Atom Has Its Own Fingerprint 2. Very Old Stars are a Blank Canvas Henry Bloomfield
22. But each one contributes less than 0.000000000000001% of the Sun’s metals Comets crash into our Sun all the time.
24. All stars like the Sun eventually run out of fuel. When they do, they lose all their envelope and only the core remains: a white dwarf star.
27. Sun White Dwarf (60% Mass of Sun) Earth (0.0003% Mass of Sun)
28. Under Gravity, Heaviest Elements Sink Sharyn Morrow A ‘Typical’ White Dwarf Carbon/Oxygen Core (r = 8500 km) Helium Layer (260 km) Outer Hydrogen Layer (30 km)
29. Most White Dwarfs: Only Hydrogen
30. Some White Dwarfs Show Metals
31. Mark Garlick
33. The Abundances Resemble Earth and Meteorites Jay Farihi 2011
34. Earth Rocks Falling on White Dwarfs Iron, Oxygen, Silicon, Magnesium Xu et al. 2014
35. Earth Rocks Falling on White Dwarfs Iron, Oxygen, Silicon, Magnesium Xu et al. 2014 Mike Jura, UCLA
38. Today Boris Gänsicke
39. 5.5 billion years from now Boris Gänsicke
40. The life cycle of the Sun 9 billion years from now Boris Gänsicke
41. 1. Take a solar system. There are likely billions in our Galaxy. 2. As the host star evolves, the orbits of planets expand. Some may scatter and collide. 3. Ancient solar systems have leftover debris. We can see it if it gets close to a white dwarf.
42. Saturn: Familiar Debris Rings
43. White Dwarfs: Debris Rings on Steroids
44. V = 13.3 mag Star Wars: A New Hope © Disney
45. V = 13.3 mag Star Wars: A New Hope © Disney
46. Mark Garlick
47. Mark Garlick A. Vanderburg et al. 2015; Gänsicke et al. 2016
48. Mark Garlick
49. We can measure the bulk abundances of rocks in extrasolar planetary systems
50. What about water?
51. Mark Garlick
52. Oxygen Excess: Water-Rich Material! Rocks = MgO, Al2 O3 , SiO2 , CaO, TiO2 , Cr2 O3 , MnO, FeO, Fe2 O3 , ... Anything Else = CO2 , H2 O Farihi et al. 2013; Raddi et al. 2015 Very little Carbon, so excess Oxygen likely H2 O! White Dwarf GD 61 Two specific white dwarfs have rocks, maybe worlds, that are roughly 25-40% water!
53. Billions of planets likely exist in the Galaxy “The Search for Life Beyond Earth…” Many of these planets are rocky, like Earth Using ancient stars, we can learn that these alien rocks are composed of the same material as Earth… including water!
54. Sheila Sund