Download - Week 10 Thursday

Transcript

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Week 10 Thursday

1

Today’s Agenda • Chemical composition of stars • Stellar interiors • Energy generation in the core • Group Problem! • Fusion

Announcements / Reminders • HW 7 due Friday 1min before midnight • Read Chapters 16.1-2 & 17 for next week

• HEAP talk at 4pm on Thursday • Theoretical dark matter candidate particle

• Colloquium at 2pm on Friday • Condensed matter theory, material properties in

Earth’s mantleVideo of Friday’s colloquium & Q&A on careers:

https://uofu.box.com/s/hve526edej6p4m7wax1lgot59wc6ff0d

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Luminosity vs Temperature

2

Te↵ =

✓L

4⇡R2�SB

◆1/4

<latexit sha1_base64="Qg76vXVSNIMzFyEInaCxdFLywRg=">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</latexit>

dPdr

= −GM( < r)ρ

r2

Hydrostatic Equilibrium

Ideal Gas Law

P = nkT =ρkTμmp

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Characterizing Composition of Stars

3

ρ = ρH + ρHe + ρmetalsX ≡ ρH/ρY ≡ ρHe/ρZ ≡ ρmetals/ρ = 1 − X − Y

X⊙ = 0.734, Y⊙ = 0.250, Z⊙ = 0.016

XBB ∼34

, YBB ∼14

, ZBB ∼ 0

P = nkT =ρkTμmp

Mean molecular mass

μH = {1 neutral12 ionized μHe = {

4 neutral43 ionized

μ(ionized) =ρ

nmp= (2X +

34

Y +12

Z)−1

μ⊙(ionized) = 0.60

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Stellar Interiors (same as atmospheres)

4

dPdr

= −GM( < r)ρ(r)

r2

ΔPΔr

≈ −G⟨M⟩⟨ρ⟩

⟨r⟩2

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Energy Generation

5

First idea: light is the latent heat from the formation of the Sun due to the conversion of gravitational potential energy to kinetic energy (heat) during collapse

U = − qGM2

Rq is a factor of order unity that depends on the density distribution ρ(r)

Lifetime of a star is simply this energy divided by the rate that energy is emitted,

i.e., the luminositytKH ≡

UL

tKH,⊙ =U⊙

L⊙≈ 50 Myr

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Group Problem

6

Mars is now tectonically dead, because it has cooled sufficiently that heat from its formation is no longer available to drive convention and activity like plate tectonics.

Using Lord Kelvin & Helmholtz’s arguments, should 🌎 Earth 🌍 still be tectonically active today?

If the answer is no, why do we have earthquakes, volcanoes, and active plate tectonics???

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Fusion possible b/c of QM

7

⇠ 10�15 m

<latexit sha1_base64="uxpj9RG6nRXf+3U0hVNdVG1OEOk=">AAAB/nicbVDLSsNAFL3xWesrKq7cDBbBjSWRirorunFZwT6giWUynbRDZ5IwMxFKiPgrblwo4tbvcOffOH0stPXAhcM593LvPUHCmdKO820tLC4tr6wW1orrG5tb2/bObkPFqSS0TmIey1aAFeUsonXNNKetRFIsAk6bweB65DcfqFQsju70MKG+wL2IhYxgbaSOve8pJpDr3Gcn7ln+mHlSIJF37JJTdsZA88SdkhJMUevYX143JqmgkSYcK9V2nUT7GZaaEU7zopcqmmAywD3aNjTCgio/G5+foyOjdFEYS1ORRmP190SGhVJDEZhOgXVfzXoj8T+vnerwws9YlKSaRmSyKEw50jEaZYG6TFKi+dAQTCQztyLSxxITbRIrmhDc2ZfnSeO07FbKl7eVUvVqGkcBDuAQjsGFc6jCDdSgDgQyeIZXeLOerBfr3fqYtC5Y05k9+APr8wfnVZTW</latexit>

U ⇡ e2

4⇡✏0r= 1.4 MeV

<latexit sha1_base64="HXrVEMHO4vCuZtK2UWAJkJdDFxY=">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</latexit>

hEi = 3

2kTc ⇡ 2 keV

<latexit sha1_base64="kSWUmCBIYeMezcsy/xNmxrysRJ4=">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</latexit>

Particles are waves!

�prot =h

p=

h

mpv⇡ 10�13 m

<latexit sha1_base64="hQ2MwdbBP2fGvR/QF5iiz2PRN5c=">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</latexit>

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Proton-proton chain: Tc < 1.8 x 107 K

8

4 p ! 4He + 2� + 2e

++ 2⌫e

<latexit sha1_base64="CGCAV6XeEsEgqT8h9bLTwli5Rus=">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</latexit>

e+ + e� ! 2�

<latexit sha1_base64="ZmUmrXlXZdquEx3ksKbbKkzQDVU=">AAACEnicbZDLSgMxFIYzXmu9VV26CRZBKZaZUlB3RTcuK9gLdGo5k2amocnMkGSUMvQZ3Pgqblwo4taVO9/G9CJo6w+Bj/+cw8n5vZgzpW37y1pYXFpeWc2sZdc3Nre2czu7dRUlktAaiXgkmx4oyllIa5ppTpuxpCA8Thte/3JUb9xRqVgU3uhBTNsCgpD5jIA2Vid3nLpSYDq8LeAC/uET7EoW9DRIGd3jkhuAENDJ5e2iPRaeB2cKeTRVtZP7dLsRSQQNNeGgVMuxY91OQWpGOB1m3UTRGEgfAtoyGIKgqp2OTxriQ+N0sR9J80KNx+7viRSEUgPhmU4BuqdmayPzv1or0f5ZO2VhnGgakskiP+FYR3iUD+4ySYnmAwNAJDN/xaQHEog2KWZNCM7syfNQLxWdcvH8upyvXEzjyKB9dICOkINOUQVdoSqqIYIe0BN6Qa/Wo/VsvVnvk9YFazqzh/7I+vgGY9Octg==</latexit>

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

Neutrino Detector

9

Super Kamiokande, Japan

ASTR/PHYS 3070: Foundations Astronomy Fall 2021: Week 10b

CNO cycle: Tc > 1.8 x 107 K

10

Carbon, Nitrogen, Oxygen used as catalysts

12C+ 4p ! 12

C+4He

<latexit sha1_base64="EiQHo6B8JAsIvgzrwF2/CA8mCFo=">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</latexit>

plus photons, neutrinos, and positrons

Triple Alpha Process4He +

4He ! 8

Be + �

<latexit sha1_base64="z1U41dTU0S4U8InqyfIlvkaONS4=">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</latexit>

8Be +

4He ! 12

C+ �

<latexit sha1_base64="5eKNmArGNXDUdrUkbqifD+/vwNc=">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</latexit>

Decays quickly, needs T > 108 K and high density so it encounters another helium nucleus (alpha

particle) before it does