APOD 13Mar18 - University of Delawareowocki/phys333/Lec12-07Apr.pdf• Use the class Zoom number:...

APOD 13Mar18

Assignments for Thurs. 09 Apr.

• Complete work on HW4.pdf; it’s due 5 p.m. Tuesday April 07.

• Midterm exam scheduled for Tues. April 14• On parts I and II of DocOnotes.pdf• online, in class format; 1 page note sheet & calculators allowed• “Mock” exam Thurs. April 09• View student instructional video at https://bit.ly/2J007J2

• Office hours: officially Monday 4:00-5:00, Thursday 2:00-3:00 • Also after class today• Use the class Zoom number: 464-648-097• Private sessions by email request to [email protected]

Convective instability

Sources of opacity

<= Much stronger

So in cool stars with neutral H near the surface,b-f opacity BLOCKS radiative diffusion.

This makes surface layersunstable to CONVECTION

dTdr rad

> dTdr ad

Solar convection

granulation super-granulation

Conditions for H-fusion

mpvth2

2= kT = e

2

r=e2

hmpvth

T =µvth

2

2k=2µe4

kh2= 17MK

Clicker QuestionAbout what core temperature is need for H fusion burning into He?

A. 15,000 K

B. 15 MK

C. 15 x 109 K

D. 1 MK

E. It depends on the star’s mass.

Clicker QuestionWhat is the likely final fate and remnant of a star with 2 Msun?

A. Planetary Nebula & Black Hole

B. Planetary Nebula & Neutron Star

C. Planetary Nebula & White Dwarf

D. Supernova & Black Hole

E. Supernova & Neutron Star

2 Ways to Fuse H into He

PP chainM < 2Msun

CNO cycleM > 2Msun

M< 8 Msun

Life cycle of low-mass star

H shell-burning: TAMS => Red Giant

Triple- burning of He into C

He capture

Stellar degeneracy

for CO

M< 8 Msun

Life cycle of low-mass star

> 8 Msun

8 Msun < M < 30Msun

1.4 Msun < M < 2.1 Msun

> 2.1 Msun

> 30Msun

Life cycle of high-mass star

< 8 Msun

> 8 Msun

< 1.4 Msun

8 Msun < M < 30Msun

1.4 Msun < M < 2.1 Msun

> 2.1 Msun

> 30Msun

< 8 Msun

> 8 Msun

< 1.4 Msun

8 Msun < M < 30Msun

1.4 Msun < M < 3 Msun

> 3 Msun

> 30Msun

https://www.ligo.caltech.edu/video/ligo20160211v1

LIGO

10−21 km = 10−18m =10−3 fmInterferometry arm = few km

1/1000 the size of a proton

Sensitivity = 10-21

First detection 14Sep15: 100 years after Einstein’s GRBH+BH: 35 Msun + 30 Msun => 62 Msun

𝛥Msun c2 = 3Msun c2 = Energy gravitational wave!L~ 3 Msun c2/0.1sec > L of all stars in universe!

GW150914

GW170817 & GRB 170817A

Seen in gamma-rays 1.7 sec after GW And later in all bands of EM waves:X-ray, UV, optical, IR, Radio

https://en.wikipedia.org/wiki/Neutron_star_merger

https://public.nrao.edu/gallery/animation-of-neutron-star-merger-and-aftermath/

APOD 13Mar18 - University of Delawareowocki/phys333/Lec12-07Apr.pdf• Use the class Zoom number:...

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