The Explosive Lives of Stars: Producing Elements in the Cauldrons of - PowerPoint PPT Presentation

The Explosive Lives of Stars: Producing Elements in the Cauldrons of the Cosmos Catherine M. Deibel Department of Physics & Astronomy Louisiana State University Conference for Women in Undergraduate Physics 01/18/14 1

13.7 Billion (13,700,000,000) years ago the universe began with THE BIG BANG Conference for Women in Undergraduate Physics 01/18/14 2

The first atoms • A fraction (1/10,000,000,000,000,000,000,000,000,000,000) of a second after the BIG BANG electrons are created Conference for Women in Undergraduate Physics 01/18/14 3

The first atoms • One millionth of a second (.000001 seconds) after the BIG BANG protons and neutrons are formed Conference for Women in Undergraduate Physics 01/18/14 4

The first atoms • 3 minutes after the BIG BANG the first atoms form Conference for Women in Undergraduate Physics 01/18/14 5

After the Big Bang Conference for Women in Undergraduate Physics 01/18/14 6

What about everything else? Aluminum (Al) Sodium (Na) Oxygen (O) in water (H 2 O) Calcium (Ca) Gold (Au) Conference for Women in Undergraduate Physics 01/18/14 7

Where does the rest of the Periodic Table come from? Conference for Women in Undergraduate Physics 01/18/14 8

Beyond the Periodic Table . . . • Adding or subtracting neutrons makes different isotopes • A hydrogen nucleus is one proton – Adding one neutron to hydrogen makes the isotope deuterium – Then adding one proton makes the isotope 3 He – Then adding one neutron makes the isotope 4 He • Total number of protons (“atomic number”) = Z • Total number of neutrons = N • N + Z = A, “atomic mass number” or number of nucleons 1 H Conference for Women in Undergraduate Physics 01/18/14 9

Beyond the Periodic Table . . . • Adding or subtracting neutrons makes different isotopes • A hydrogen nucleus is one proton – Adding one neutron to hydrogen makes the isotope deuterium – Then adding one proton makes the isotope 3 He – Then adding one neutron makes the isotope 4 He • Total number of protons (“atomic number”) = Z • Total number of neutrons = N • N + Z = A, “atomic mass number” or number of nucleons 1 H 2 H Conference for Women in Undergraduate Physics 01/18/14 9

Beyond the Periodic Table . . . • Adding or subtracting neutrons makes different isotopes • A hydrogen nucleus is one proton – Adding one neutron to hydrogen makes the isotope deuterium – Then adding one proton makes the isotope 3 He – Then adding one neutron makes the isotope 4 He • Total number of protons (“atomic number”) = Z • Total number of neutrons = N • N + Z = A, “atomic mass number” or number of nucleons 3 He 1 H 2 H Conference for Women in Undergraduate Physics 01/18/14 9

Beyond the Periodic Table . . . • Adding or subtracting neutrons makes different isotopes • A hydrogen nucleus is one proton – Adding one neutron to hydrogen makes the isotope deuterium – Then adding one proton makes the isotope 3 He – Then adding one neutron makes the isotope 4 He • Total number of protons (“atomic number”) = Z • Total number of neutrons = N • N + Z = A, “atomic mass number” or number of nucleons A X or Z A X 3 4 He He 1 H 2 protons + neutrons H Conference for Women in Undergraduate Physics 01/18/14 9

Beyond the Periodic Table . . . • Keep adding protons and neutrons to make thousands of isotopes Conference for Women in Undergraduate Physics 01/18/14 10

Where does the rest of the Periodic Table come from? Conference for Women in Undergraduate Physics 01/18/14 11

Where does the rest of the Periodic Table come from? Conference for Women in Undergraduate Physics 01/18/14 11

Different Nuclei are produced in different stars Conference for Women in Undergraduate Physics 01/18/14 12

Conference for Women in Undergraduate Physics 01/18/14 !" D.K. Galloway et al. , ApJ 601 466 (2004).

Neutron Stars • Neutron stars are extremely compact, dense objects ( ! ~ 10 14 g/cm 2 ) Conference for Women in Undergraduate Physics 01/18/14 14

Neutron Stars • Neutron stars are extremely compact, dense objects ( ! ~ 10 14 g/cm 2 ) Conference for Women in Undergraduate Physics 01/18/14 14

Conference for Women in Undergraduate Physics 01/18/14 !# D.K. Galloway et al. , ApJ 601 466 (2004).

X-Ray Burst Z+2 Z+2 Z+2 Nucleosynthesis N N+1 N+2 Proton capture: (p, γ ) Z+1 Z+1 Z+1 N N+1 N+2 Proton decay: ( γ ,p) Beta decay: Z Z Z ( β + ) N N+1 N+2 Alpha capture: ( α , γ ) Z-1 Z-1 ( α , p) N N+1 18 Conference for Women in Undergraduate Physics 01/18/14

X-Ray Burst Nucleosynthesis www.jinaweb.org Conference for Women in Undergraduate Physics 01/18/14 19

How do nuclei react? • $%&'()*( a reaction rate ? (i.e. What is the probability of two nuclei reacting in the stellar plasma?) • Thermal distribution of nuclei in stellar plasma: Maxwell-Boltzmann distribution • The probability of the interaction between two nuclei: nuclear cross section • Temperature dependent - di fg erent temperatures in stars probe di fg erent energies in nucleus Conference for Women in Undergraduate Physics 01/18/14 20

Reaction Rates • !"#$%&'()*+( !"#$%&&'()&*+,"--./01*20345)- (%&(,%)*()*+( -46&%"2.62)11.1%65)-.. '%-+.()*+( 2%"65)-.2"*% • !"/(/+."&0&)(/+012"&(/0)+.3 - ! exp ( -E ) - ! nuclear spin, J - ! nuclear widths , " E x , J p 0,1,2 • 4,"(,05.()"(.)6$5(/+012"&.(/0)+.(0&$(1/"..(.+12"&.3 α - 7%/+1)#58(9+0.6/%&'()*+(/+012"&(/0)+(%).+#: - ;&$%/+1)#58($+)+/9%&%&'($%<+/+&)(1"9="&+&).(":()*+( /+012"&(/0)+ g.s. g.s. 34 Ar g.s. 33 Cl • +>'>( "+ ?(@ ! A=B "" C# 30 S Conference for Women in Undergraduate Physics 01/18/14 21

Studying Nuclear Reactions in the Laboratory • Using accelerators with different types of detectors we can measure what nuclear reactions happen in stars • A particle beam is accelerated and impinges on a target DETECTOR • Outgoing particles are detected beam " target Conference for Women in Undergraduate Physics 01/18/14 22

Studying Nuclear Reactions in the Laboratory • Charged particles can be manipulated by magnetic fields and separated by – charge – mass – energy • Detected using – ionization chambers – silicon detectors – CsI detectors – gamma detectors Conference for Women in Undergraduate Physics 01/18/14 23

HELIcal Orbit Spectrometer Prototype • Beam of radioactive nuclei directed Target fan Si array Si array through center of solenoid • Impinges on a target of light nuclei (e.g. Beam Recoil Detector hydrogen, helium, etc.) • Reaction products measured by detectors • Reaction products tell us: – excitation energy levels – spins of levels – reaction rate information States in 18 O from 14 O( 6 Li, d ) 18 O Excited States in 18 O (MeV) Conference for Women in Undergraduate Physics 01/18/14 24

33 Cl( p, ! ) 30 S Measurement Rotatable arm Conference for Women in Undergraduate Physics 01/18/14 25

( ! , p )-process waiting points: 30 S( ! , p ) 33 Cl Measurement J.L. Fisker et al., ApJ 608, L61 • ( ! ,p ) reactions on waiting points (2004). ( 22 Mg, 26 Si, 30 S, and 34 Ar) may have significant effects on type I X-ray bursts 30 S( ! 0 , p ) 33 Cl – final elemental abundances – energy generation (b) 10 2 – double-peaked luminosity profiles Cross Section (mb) 10 1 ( ! 0 , p ) NON-SMOKER • Measured cross sections converted ( ! 0 , p 0 ) data 10 0 (probability of reacting) larger than theoretical predictions: 4 5 6 c. m. Energy (MeV) – reaction rate is bigger! C.M. Deibel ett al , submitted (2011). Conference for Women in Undergraduate Physics 01/18/14 26

Experiments for X-ray bursts Array for Nuclear Astrophysics Studies with Exotic Nuclei (ANASEN) Up to 1300 cm 2 of 1-mm-thick Si backed with 2-cm-thick CsI Up to 3 rings of 12 modules in barrel formation Active target+detector Annular gas proportional Annular array for forward/ counter surrounds beam axis backward angles IC ANASEN Conference for Women in Undergraduate Physics 01/18/14 27

Conference for Women in Undergraduate Physics 01/18/14 28

Embarrassing truths about NA a.k.a. why we stay employed Cowan & Sneden, Nature 440 (2006) 1151. • Supernova models don’t explode • We don’t know where all the heavy elements are made • Most reactions that happen in stars have not been studied Z>55 pattern matches solar Conference for Women in Undergraduate Physics 01/18/14 29

Embarrassing truths about NA a.k.a. why we stay employed • Supernova models don’t explode • We don’t know where all the heavy elements are made • Most reactions that happen in stars have not been studied • But the future is bright . . . Conference for Women in Undergraduate Physics 01/18/14 30

Embarrassing truths about NA a.k.a. why we stay employed • Supernova models don’t explode • We don’t know where all the heavy elements are made • Most reactions that happen in stars have not been studied • But the future is bright . . . Conference for Women in Undergraduate Physics 01/18/14 30