1. NEUTRON STARS

2. • Proposed by Walter Baade & Fritz Zwicky in
1934
• Jocelyn Bell Burnell and Antony Hewish in
1967 – LGM-1
• Now more than 2000 discovered
HISTORY OF DISCOVERY

4. THE LIFE AND DEATH
OF STARS

6. SMALLER STARS (LIKE OUR SUN)
( Don’t worry, we have around 5
billions years left yet … )

8. ALL ABOUT MASS OF CORE REMNANT
< 1.4 Solar Masses = White dwarf
1.4 - ~3 Solar Masses = Neutron star
> 3 Solar Masses = Black hole

9. MASS OF ORIGINAL STAR
< 10 Solar masses = White dwarf
10 – 29 Solar masses = Neutron star
> 29 Solar masses = Black hole

10. SOME OTHER SCENARIOS….
• Some stars may just vanish to black hole instantly
• Some huge stars blow up entirely, leaving NOTHING
• Some may form Quark Stars

11. NEUTRON STAR
• All empty space of atoms squeezed away
• Density of an atom core
• Tight structure of neutrons
• Matchbox of material = 13m tonnes
• Cube of Earth 135m square

12. VERY DENSE!

13. VERY DENSE!

14. VERY, VERY DENSE!

15. STRUCTURE OF NEUTRON STARS

16. BENDING LIGHT

17. SPIN RATE
Conservation
of angular
momentum

18. SPIN RATE
Spin Up -
Angular
momentum
transferred
from accreting
material

19. SPIN RATE
• MSP – fastest 700x / second!
• 24% the speed of light!
• Upper limit 1500 x ?
• Slow as they age and stop accreting
• Slowest yet found – 6.7 hrs

20. TYPES OF NEUTRON STARS
• “Quiet” neutron stars, non emitting
• Binary pair
• Pulsars
• Magnetars

21. BINARY PAIR

22. PULSARS

23. PULSARS
• Highly magnetic, emit beams of energy
• Very, very precise spin rates
• Spinning from every few seconds, to
700 x per second
• 23% of the speed of light!
• Potential uses as deep space GPS signals
• Pulsar clock built in Gdańsk

24. PULSARS

25. CRAB NEBULA & PULSAR

28. MAGNETARS
• Even more powerful magnetic field
• Rotate more slowly ( 1 – 10 seconds )
• Strong bursts of x-rays and gamma rays
• Magnetic fields tend to decay after 10,000 years
• 30m estimated inactive magnetars in Milky Way

29. MAGNETARS

30. HOW COMMON?
• Estimated at 1bn in Milky Way
• Only 2000 found so far
• Many are old and have slowed, lost energy
• Nearest to us ~280 light years away

31. WHAT HAPPENS TO YOU
IF YOU GET CLOSE TO NEUTRON STAR?

33. QUESTIONS?