Pulsars ASTR2110 Sarazin. Crab Pulsar in X-rays

Size: px
Start display at page:

Download "Pulsars ASTR2110 Sarazin. Crab Pulsar in X-rays"

Transcription

1 Pulsars ASTR2110 Sarazin Crab Pulsar in X-rays

2 Test #2 Monday, November 13, 11-11:50 am Ruffner G006 (classroom) Bring pencils, paper, calculator You may not consult the text, your notes, or any other materials or any person You may bring a 3x5 card with equations ~2/3 Quantitative Problems (like homework problems) ~1/3 Qualitative Questions Multiple Choice, Short Answer, Fill In the Blank questions No essay questions

3 Test #1 (Cont.) Equation/Formula Card: You may bring one 3x5 inch index card with equations and formulae written on both sides. DO NOT LIST pc, AU, M, L, R DO NOT INCLUDE ANY QUALITATIVE MATERIAL (text, etc.)

4 Material: Test #2 (Cont.) Chapters 5, 7, , 14, 15, 17, 18, 23.3 Binary Stars, the Sun, Atomic Physics, Stellar Spectra and Atmospheres, Stellar Interiors, Nuclear Energy, Stellar Evolution, Stellar Remnants, General Relativity, Black Holes, Stellar Deaths, Neutron Stars and Pulsars (Quantitative problems only) (Qualitative problems only) Homeworks 6-9 Know pc, AU, M, L, R

5 Material: Test #2 (Cont.) Chapters 5, 7, , 14, 15, 17, 18, 23.3 Binary Stars, the Sun, Atomic Physics, Stellar Spectra and Atmospheres, Stellar Interiors, Nuclear Energy, Stellar Evolution, Stellar Remnants, General Relativity, Black Holes, Stellar Deaths, Neutron Stars and Pulsars (Quantitative problems only) Homeworks 6-9 Know pc, AU, M, L, R

6 Test #2 (Cont.) No problem set week of November 6 13 to allow study for test Review Session: Discussion session Friday, November 10, 3-4 pm

7 Pulsars ASTR2110 Sarazin Crab Pulsar in X-rays

8 Pulse Profile: Radio

9 Pulsars: Properties mid 1968 Periods: P = seconds d P / dt < sec/sec, very good clock dp/dt > 0, pulses slowing very slightly Pulse duration >~ 20 ms

10 Pulsars = Rotating Neutron Stars

11 Crab Pulsar

12 Crab Pulsar 1968 P = sec dp/dt = 4 x t slow ~ P/(dP/dt) ~ 2000 years ~ time since supernova Decrease in rotational kinetic energy = energy from Crab Nebula

13 Crab Pulsar Rotational kinetic energy = (1/2) I Ω 2 = (1/2) I (2π/P) 2 I = moment of inertia ~ M R 2 ~10 45 gm cm 2 Decrease in rotational kinetic energy ~ 2 x erg/s ~ energy from Crab Nebula Energy for pulsar, nebula due to rotational kinetic energy of neutron star 1.4 M 8 10 km

14 Pulsar Model Neutron stars formed by collapse of core of star to ~10 km Core rotating, magnetic field Angular Momentum Conservation Core rotation speeds up to P ~ sec Magnetic field frozen-in Magnetic field increases to ~10 12 G = pulsar ~10 14 G = magnetar New NSs rotate rapidly, highly magnetized

15 Pulsar Model (Cont.) Most astrophysical objects have magnetic fields which are (at least) slightly miss-aligned with their rotation axis. Earth, Sun, other planets, most stars Rotating magnets = changing B field = generator NS with P ~ sec, B ~ G generates V!! Pull particles [electrons, positrons, protons(?)] from NS Beams of particles shoot out along field lines, radiate Rotating beams of emission, lighthouse

16 Pulsar Model

17 Pulsar Model

18 Pulsar Model

19 Fermi Gamma-Only Pulsars

20 How Does Pulsar Power Crab Nebula? Pulsar Wind Nebulae red = optical blue = X-ray

21 Crab Chandra Xray Pulsar Wind Nebulae

22 Pulsar Wind Nebulae

23 Pulsar Wind Nebulae Vela Pulsar Chandra Xray

24 Related Neutron Stars

25 P-Pdot diagram Related Neutron Stars

26 P-Pdot diagram Age (dash) Magnetic field (dashdot) Spin-down luminosity (dash-dot) Line of Death (solid) Related Neutron Stars

27 Young radio pulsars Crab, Vela Often still in supernova remnants (stars) Related Neutron Stars

28 Young radio pulsars Crab, Vela Often still in supernova remnants (stars) Related Neutron Stars Crab pulsar

29 Young radio pulsars Crab, Vela Often still in supernova remnants (stars) Related Neutron Stars Vela pulsar

30 Young radio pulsars Crab, Vela Often still in supernova remnants (stars) Related Neutron Stars

31 Young radio pulsars Crab, Vela Often still in supernova remnants (stars) Normal, middle aged radio pulsars Related Neutron Stars

32 Life history of normal radio pulsar Born fast, strong magnetic field Slow down, B gets weaker Stops emitting pulses Related Neutron Stars

33 Millisecond Radio Pulsars Very fast rotation Very weak magnetic field Very Accurate Clocks Many in globular clusters Most are binaries (circles) Related Neutron Stars

34 Millisecond Pulsars in Globular Cluster

35 Millisecond Radio Pulsars Very fast rotation Very weak magnetic field Very Accurate Clocks Many in globular clusters Most are binaries (circles) Not on life track of normal radio pulsars How are they made? Related Neutron Stars

36 Magnetars Very Strong Magnetic Field Slow rotation NOT RADIO PULSARS X-ray Sources Soft Gamma Repeaters Powered by magnetic energy, not rotation Related Neutron Stars

37 Magnetars Very Strong Magnetic Field Slow rotation NOT RADIO PULSARS X-ray Sources Soft Gamma Repeaters Powered by magnetic energy, not rotation Related Neutron Stars

38 Magnetars Very Strong Magnetic Field Slow rotation NOT RADIO PULSARS X-ray Sources Soft Gamma Repeaters Powered by magnetic energy, not rotation Related Neutron Stars

39 Magnetars Very Strong Magnetic Field Slow rotation NOT RADIO PULSARS X-ray Sources Soft Gamma Repeaters Powered by magnetic energy, not rotation Related Neutron Stars

40 Anti-Magnetars Weak Magnetic Field Fast rotation? NOT RADIO PULSARS X-ray Sources Central source in Cas-A SNR Related Neutron Stars

41 Anti-Magnetars Weak Magnetic Field Fast rotation? NOT RADIO PULSARS X-ray Sources Central source in Cas-A SNR Related Neutron Stars

42 End of Material for Test 2

43 Compact Binaries ASTR2110 Sarazin

44 Neat Dead Stars White Dwarf (WD) Neutron Star (NS) Black Hole (BH) But, dead, so no energy = no light?

45 Binary Stars! 1/2 of stars are in binaries More massive star will die first Second star will become a giant, dump gas onto stellar corpse Accreting WDs = Cataclysmic Variables = CVs Accreting NSs or BHs = X-ray Binaries

46 Stellar Evolution in Close Binaries Close a radius of giant star ~ AU, P year Tidal Evolution Close strong tidal distortion of stars

47 Stellar Evolution in Close Binaries Close a radius of giant star ~ AU, P year Tidal Evolution Close strong tidal distortion of stars Tidal Friction Synchronize rotation, orbit Circular orbit Rotation axes aligned Rotation axes = orbital axis P rot = P orb Lowest energy state Moon is an example, many others in the Solar System

48 Roche Geometry Go to rotating frame on CM, P = P rot = P orb everything is stationary Need to include centrifugal acceleration, Coriolis effect Define effective potential energy as gravity of two stars plus centrifugal acceleration

49 Roche Potential PE = Potential Energy orbital plane

50 Shapes of Stars in Binaries Single non-rotating star = sphere What is shape of star with rotation, and/or in binary? At surface, P = 0 no pressure forces along surface No gravitational + centrifugal force parallel to surface or material would move F

51 Shapes of Stars in Binaries No gravitational + centrifugal force parallel to surface ΔPE = F ds along surface = 0 PE = constant on stellar surface, including all gravity and centrifugal forces Stellar surfaces are equipotentials

52 Roche Potential PE = Potential Energy orbital plane

53 Roche Potential Project equipotentials onto orbital plane

54 Shapes of Stars in Binaries Small stars = spheres Larger stars distorted, egg-shaped Equipotentials in orbital plane

55 Shapes of Stars in Binaries Small stars = spheres Larger stars distorted, egg-shaped

56 Shapes of Stars in Binaries Small stars = spheres Larger stars distorted, egg-shaped Roche lobe = separate regions for two stars Roche lobes meet at Inner Lagrangian Point L1 Equipotentials in orbital plane (5 Lagrangian points, where force = 0)

57 Mass Transfer in Binaries Higher mass star bigger Roche lobe If a star expands, material will first pass through L1 to other star Mass Transfer If M tot = M 1 + M 2 = constant and angular momentum is conserved, mass transfer decreases size of Roche lobe of losing star R 1 minimum when M 1 /M tot = 0.4 Mass transfer continues until more massive star becomes least massive

58 Stellar Evolution in Binaries 1. Two stars form in a close binary a R 1 (giant), M 1 M 2 2. Tidal Friction Synchronize rotation, orbit 3. Star 1 evolves first, becomes giant, overflows Roche lobe, mass transfer to star 2 4. Mass transfer continues until M 1 < (2/3) M 2 More massive star (initially) becomes least massive

59 Algol Paradox In many close binary star systems, there is a lower mass evolved star and a higher mass main sequence star. Algol: eclipsing binary with lower mass K giant star and higher mass B main sequence star Mystery (originally): why didn t the more massive star become a giant first?

Black Holes ASTR 2110 Sarazin. Calculation of Curved Spacetime near Merging Black Holes

Black Holes ASTR 2110 Sarazin. Calculation of Curved Spacetime near Merging Black Holes Black Holes ASTR 2110 Sarazin Calculation of Curved Spacetime near Merging Black Holes Test #2 Monday, November 13, 11-11:50 am Ruffner G006 (classroom) Bring pencils, paper, calculator You may not consult

More information

Evolution of High Mass stars

Evolution of High Mass stars Evolution of High Mass stars Neutron Stars A supernova explosion of a M > 8 M Sun star blows away its outer layers. The central core will collapse into a compact object of ~ a few M Sun. Pressure becomes

More information

7. BINARY STARS (ZG: 12; CO: 7, 17)

7. BINARY STARS (ZG: 12; CO: 7, 17) 7. BINARY STARS (ZG: 12; CO: 7, 17) most stars are members of binary systems or multiple systems (triples, quadruples, quintuplets,...) orbital period distribution: P orb = 11 min to 10 6 yr the majority

More information

Chapter 14. Outline. Neutron Stars and Black Holes. Note that the following lectures include. animations and PowerPoint effects such as

Chapter 14. Outline. Neutron Stars and Black Holes. Note that the following lectures include. animations and PowerPoint effects such as Note that the following lectures include animations and PowerPoint effects such as fly ins and transitions that require you to be in PowerPoint's Slide Show mode (presentation mode). Chapter 14 Neutron

More information

FORMATION AND EVOLUTION OF COMPACT BINARY SYSTEMS

FORMATION AND EVOLUTION OF COMPACT BINARY SYSTEMS FORMATION AND EVOLUTION OF COMPACT BINARY SYSTEMS Main Categories of Compact Systems Formation of Compact Objects Mass and Angular Momentum Loss Evolutionary Links to Classes of Binary Systems Future Work

More information

Chapter 14: The Bizarre Stellar Graveyard. Copyright 2010 Pearson Education, Inc.

Chapter 14: The Bizarre Stellar Graveyard. Copyright 2010 Pearson Education, Inc. Chapter 14: The Bizarre Stellar Graveyard Assignments 2 nd Mid-term to be held Friday Nov. 3 same basic format as MT1 40 mult. choice= 80 pts. 4 short answer = 20 pts. Sample problems on web page Origin

More information

The Milky Way - 2 ASTR 2110 Sarazin. Center of the Milky Way

The Milky Way - 2 ASTR 2110 Sarazin. Center of the Milky Way The Milky Way - 2 ASTR 2110 Sarazin Center of the Milky Way Final Exam Tuesday, December 12, 9:00 am noon Ruffner G006 (classroom) You may not consult the text, your notes, or any other materials or any

More information

Stellar Interiors ASTR 2110 Sarazin. Interior of Sun

Stellar Interiors ASTR 2110 Sarazin. Interior of Sun Stellar Interiors ASTR 2110 Sarazin Interior of Sun Test #1 Monday, October 9, 11-11:50 am Ruffner G006 (classroom) You may not consult the text, your notes, or any other materials or any person Bring

More information

Accretion in Binaries

Accretion in Binaries Accretion in Binaries Two paths for accretion Roche-lobe overflow Wind-fed accretion Classes of X-ray binaries Low-mass (BH and NS) High-mass (BH and NS) X-ray pulsars (NS) Be/X-ray binaries (NS) Roche

More information

Neutron Stars. Properties of Neutron Stars. Formation of Neutron Stars. Chapter 14. Neutron Stars and Black Holes. Topics for Today s Class

Neutron Stars. Properties of Neutron Stars. Formation of Neutron Stars. Chapter 14. Neutron Stars and Black Holes. Topics for Today s Class Foundations of Astronomy 13e Seeds Phys1403 Introductory Astronomy Instructor: Dr. Goderya Chapter 14 Neutron Stars and Black Holes Cengage Learning 2016 Topics for Today s Class Neutron Stars What is

More information

21. Neutron Stars. The Crab Pulsar: On & Off. Intensity Variations of a Pulsar

21. Neutron Stars. The Crab Pulsar: On & Off. Intensity Variations of a Pulsar 21. Neutron Stars Neutron stars were proposed in the 1930 s Pulsars were discovered in the 1960 s Pulsars are rapidly rotating neutron stars Pulsars slow down as they age Neutron stars are superfluid &

More information

Compact Binaries - 3 ASTR2110 Sarazin

Compact Binaries - 3 ASTR2110 Sarazin Compact Binaries - 3 ASTR2110 Sarazin Zoology of Binary Stars X-ray Binary Pulsar Spin-Up Accreted material has high angular momentum Spins up neutron star (true of ~all X-ray binary pulsars) Millisecond

More information

Neutron Stars. We now know that SN 1054 was a Type II supernova that ended the life of a massive star and left behind a neutron star.

Neutron Stars. We now know that SN 1054 was a Type II supernova that ended the life of a massive star and left behind a neutron star. Neutron Stars Neutron Stars The emission from the supernova that produced the crab nebula was observed in 1054 AD by Chinese, Japanese, Native Americans, and Persian/Arab astronomers as being bright enough

More information

Chapter 18 The Bizarre Stellar Graveyard

Chapter 18 The Bizarre Stellar Graveyard Chapter 18 The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf? White Dwarfs White

More information

Stellar Spectra ASTR 2110 Sarazin. Solar Spectrum

Stellar Spectra ASTR 2110 Sarazin. Solar Spectrum Stellar Spectra ASTR 2110 Sarazin Solar Spectrum Test #1 Monday, October 9, 11-11:50 am Ruffner G006 (classroom) You may not consult the text, your notes, or any other materials or any person Bring pencils,

More information

Distribution of X-ray binary stars in the Galaxy (RXTE) High-Energy Astrophysics Lecture 8: Accretion and jets in binary stars

Distribution of X-ray binary stars in the Galaxy (RXTE) High-Energy Astrophysics Lecture 8: Accretion and jets in binary stars High-Energy Astrophysics Lecture 8: Accretion and jets in binary stars Distribution of X-ray binary stars in the Galaxy (RXTE) Robert Laing Primary Compact accreting binary systems Compact star WD NS BH

More information

The Bizarre Stellar Graveyard

The Bizarre Stellar Graveyard The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf? White Dwarfs White dwarfs

More information

A100 Exploring the Universe: Stellar Remnants. Martin D. Weinberg UMass Astronomy

A100 Exploring the Universe: Stellar Remnants. Martin D. Weinberg UMass Astronomy A100 Exploring the Universe: Stellar Remnants Martin D. Weinberg UMass Astronomy astron100-mdw@courses.umass.edu March 24, 2015 Read: S3, Chap 18 03/24/15 slide 1 Exam #2: March 31 One week from today!

More information

11/1/16. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard

11/1/16. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard Important Stuff (Section 001: 9:45 am) The Second Midterm is Thursday, November 10 The Second Midterm will be given in a different room: Willey 175 Bring 2 pencils and a photo-id. In accordance with the

More information

Astronomy 421. Lecture 23: End states of stars - Neutron stars

Astronomy 421. Lecture 23: End states of stars - Neutron stars Astronomy 421 Lecture 23: End states of stars - Neutron stars 1 Outline Neutron stars Pulsars properties distribution emission mechanism evolution 2 Neutron stars Typical values: M ~ 1.4M R ~ 10 km ρ ~

More information

Pulsars. The maximum angular frequency of a spinning star can be found by equating the centripetal and gravitational acceleration M R 2 R 3 G M

Pulsars. The maximum angular frequency of a spinning star can be found by equating the centripetal and gravitational acceleration M R 2 R 3 G M Pulsars Pulsating stars were discovered in 1967 via radio dipole antennae by Jocelyn Bell and Anthony Hewish Pulse period of PSR 1919+21 is 1.337 s Most pulsars have periods between 0.25 s and 2 s The

More information

Chapter 13 Notes The Deaths of Stars Astronomy Name: Date:

Chapter 13 Notes The Deaths of Stars Astronomy Name: Date: Chapter 13 Notes The Deaths of Stars Astronomy Name: Date: I. The End of a Star s Life When all the fuel in a star is used up, will win over pressure and the star will die nuclear fuel; gravity High-mass

More information

Chapter 14: The Bizarre Stellar Graveyard

Chapter 14: The Bizarre Stellar Graveyard Lecture Outline Chapter 14: The Bizarre Stellar Graveyard 14.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf?

More information

The Stellar Graveyard

The Stellar Graveyard Life and Death of High Mass Stars (M > 8 M sun ) AST 101 Introduction to Astronomy: Stars & Galaxies Last stage: Iron core surrounded by shells of increasingly lighter elements. Announcements MIDTERM #2

More information

A100 Exploring the Universe: Stellar Remnants. Martin D. Weinberg UMass Astronomy

A100 Exploring the Universe: Stellar Remnants. Martin D. Weinberg UMass Astronomy A100 Exploring the Universe: Stellar Remnants Martin D. Weinberg UMass Astronomy astron100-mdw@courses.umass.edu October 28, 2014 Read: S3, Chap 18 10/28/14 slide 1 Exam #2: November 04 One week from today!

More information

Chapter 18 Reading Quiz Clickers. The Cosmic Perspective Seventh Edition. The Bizarre Stellar Graveyard Pearson Education, Inc.

Chapter 18 Reading Quiz Clickers. The Cosmic Perspective Seventh Edition. The Bizarre Stellar Graveyard Pearson Education, Inc. Reading Quiz Clickers The Cosmic Perspective Seventh Edition The Bizarre Stellar Graveyard 18.1 White Dwarfs What is a white dwarf? What can happen to a white dwarf in a close binary system? What supports

More information

Neutron Stars. Chapter 14: Neutron Stars and Black Holes. Neutron Stars. What s holding it up? The Lighthouse Model of Pulsars

Neutron Stars. Chapter 14: Neutron Stars and Black Holes. Neutron Stars. What s holding it up? The Lighthouse Model of Pulsars Neutron Stars Form from a 8-20 M Sun star Chapter 14: Neutron Stars and Black Holes Leftover 1.4-3 M Sun core after supernova Neutron Stars consist entirely of neutrons (no protons) Neutron Star (tennis

More information

6 th lecture of Compact Object and Accretion, Master Programme at Leiden Observatory

6 th lecture of Compact Object and Accretion, Master Programme at Leiden Observatory 6 th lecture of Compact Object and Accretion, Master Programme at Leiden Observatory Accretion 1st class study material: Chapter 1 & 4, accretion power in astrophysics these slides at http://home.strw.leidenuniv.nl/~emr/coa/

More information

ASTR Midterm 2 Phil Armitage, Bruce Ferguson

ASTR Midterm 2 Phil Armitage, Bruce Ferguson ASTR 1120-001 Midterm 2 Phil Armitage, Bruce Ferguson SECOND MID-TERM EXAM MARCH 21 st 2006: Closed books and notes, 1 hour. Please PRINT your name and student ID on the places provided on the scan sheet.

More information

The Stellar Graveyard Neutron Stars & White Dwarfs

The Stellar Graveyard Neutron Stars & White Dwarfs The Stellar Graveyard Neutron Stars & White Dwarfs White Dwarfs White dwarfs are the remaining cores of low-mass (M < 8M sun ) stars Electron degeneracy pressure supports them against gravity Density ~

More information

Chapter 18 The Bizarre Stellar Graveyard. White Dwarfs. What is a white dwarf? Size of a White Dwarf White Dwarfs

Chapter 18 The Bizarre Stellar Graveyard. White Dwarfs. What is a white dwarf? Size of a White Dwarf White Dwarfs Chapter 18 The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf? White Dwarfs White

More information

READ: Chapter 11.1, 11.2 (11.2.1, only), 11.3(

READ: Chapter 11.1, 11.2 (11.2.1, only), 11.3( HW READ: Chapter 11.1, 11.2 (11.2.1,11.2.2 only), 11.3( 11.3.1,11.3.2 only), 11.4,11.5 Question 11.2(HW#15) Problems 1(HW#16) (part a: recall: basic KE=1/2mv 2,Part tb: recall momentum conservation M f

More information

Degenerate Matter and White Dwarfs

Degenerate Matter and White Dwarfs Degenerate Matter and White Dwarfs Summary of Post-Main-Sequence Evolution of Sun-Like Stars Formation of a Planetary Nebula Fusion stops at formation of C,O core. Core collapses; outer shells bounce off

More information

Ch. 16 & 17: Stellar Evolution and Death

Ch. 16 & 17: Stellar Evolution and Death Ch. 16 & 17: Stellar Evolution and Death Stars have lives: born, evolve, die Mass determines stellar evolution: Really Low Mass (0.08 to 0.4 M sun ) Low Mass: (0.4 to 4 M sun ) Long lives High Mass (4

More information

Astronomy. Chapter 15 Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes

Astronomy. Chapter 15 Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes Astronomy Chapter 15 Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes are hot, compact stars whose mass is comparable to the Sun's and size to the Earth's. A. White dwarfs B. Neutron stars

More information

The April Brooks Observatory sessions

The April Brooks Observatory sessions The April Brooks Observatory sessions Because of our poor weather this semester, additional observing sessions have been scheduled for ASTR 1010, beginning at 8:45 PM each evening: Sunday, April 13 through

More information

Astronomy Ch. 22 Neutron Stars and Black Holes. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Astronomy Ch. 22 Neutron Stars and Black Holes. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Name: Period: Date: Astronomy Ch. 22 Neutron Stars and Black Holes MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) In a neutron star, the core

More information

11/1/17. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard

11/1/17. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard 11/1/17 Important Stuff (Section 001: 9:45 am) The Second Midterm is Thursday, November 9 The Second Midterm will be given in a different room: Willey 175 Bring 2 pencils and a photo-id. In accordance

More information

Dr. Reed L. Riddle. Close binaries, stellar interactions and novae. Guest lecture Astronomy 20 November 2, 2004

Dr. Reed L. Riddle. Close binaries, stellar interactions and novae. Guest lecture Astronomy 20 November 2, 2004 Dr. Reed L. Riddle Close binaries, stellar interactions and novae Guest lecture Astronomy 20 November 2, 2004 Gravitational Tides Look at the forces acting on one body orbiting another - more pull on closer

More information

This class: Life cycle of high mass stars Supernovae Neutron stars, pulsars, pulsar wind nebulae, magnetars Quark-nova stars Gamma-ray bursts (GRBs)

This class: Life cycle of high mass stars Supernovae Neutron stars, pulsars, pulsar wind nebulae, magnetars Quark-nova stars Gamma-ray bursts (GRBs) This class: Life cycle of high mass stars Supernovae Neutron stars, pulsars, pulsar wind nebulae, magnetars Quark-nova stars Gamma-ray bursts (GRBs)!1 Cas$A$ All$Image$&$video$credits:$Chandra$X7ray$ Observatory$

More information

Supernovae, Neutron Stars, Pulsars, and Black Holes

Supernovae, Neutron Stars, Pulsars, and Black Holes Supernovae, Neutron Stars, Pulsars, and Black Holes Massive stars and Type II supernovae Massive stars (greater than 8 solar masses) can create core temperatures high enough to burn carbon and heavier

More information

Neutron Stars. Neutron Stars and Black Holes. The Crab Pulsar. Discovery of Pulsars. The Crab Pulsar. Light curves of the Crab Pulsar.

Neutron Stars. Neutron Stars and Black Holes. The Crab Pulsar. Discovery of Pulsars. The Crab Pulsar. Light curves of the Crab Pulsar. Chapter 11: Neutron Stars and Black Holes A supernova explosion of an M > 8 M sun star blows away its outer layers. Neutron Stars The central core will collapse into a compact object of ~ a few M sun.

More information

Analyzing X-Ray Pulses from Stellar Cores Pencil & Paper Version

Analyzing X-Ray Pulses from Stellar Cores Pencil & Paper Version Analyzing X-Ray Pulses from Stellar Cores Pencil & Paper Version Purpose: To determine if two end products of stellar evolution GK Per and Cen X-3 could be white dwarfs or neutron stars by calculating

More information

Neutron Stars. Neutron Stars Mass ~ 2.0 M sun! Radius ~ R sun! isolated neutron stars first seen only recently (1997)

Neutron Stars. Neutron Stars Mass ~ 2.0 M sun! Radius ~ R sun! isolated neutron stars first seen only recently (1997) Neutron Stars 1 2 M core > 1.4 M - collapse past WD! sun nuclei packed tightly together! protons absorb electrons; only neutrons left! collapse halted by neutron degeneracy pressure How do you find something

More information

Astronomy 114. Lecture 22: Neutron Stars. Martin D. Weinberg. UMass/Astronomy Department

Astronomy 114. Lecture 22: Neutron Stars. Martin D. Weinberg. UMass/Astronomy Department Astronomy 114 Lecture 22: Neutron Stars Martin D. Weinberg weinberg@astro.umass.edu UMass/Astronomy Department A114: Lecture 22 02 Apr 2007 Read: Ch. 23,24 Astronomy 114 1/20 Announcements PS#5 due Wednesday

More information

Physics 314 (Survey of Astronomy) Exam 1

Physics 314 (Survey of Astronomy) Exam 1 Physics 314 (Survey of Astronomy) Exam 1 Please show all significant steps clearly in all problems. Please give clear and legible responses to qualitative questions. See the last page for values of constants.

More information

Chapter 13: The Stellar Graveyard

Chapter 13: The Stellar Graveyard Chapter 13: The Stellar Graveyard Habbal Astro110 http://chandra.harvard.edu/photo/2001/1227/index.html Chapter 13 Lecture 26 1 Low mass star High mass (>8 M sun ) star Ends as a white dwarf. Ends in a

More information

Planetary Nebulae evolve to White Dwarf Stars

Planetary Nebulae evolve to White Dwarf Stars Planetary Nebulae evolve to White Dwarf Stars Planetary Nebulae When Red Giant exhausts its He fuel the C core contracts Low & medium-mass stars don t have enough gravitational energy to heat to core 6

More information

Chapter 13 2/19/2014. Lecture Outline Neutron Stars. Neutron Stars and Black Holes Neutron Stars. Units of Chapter

Chapter 13 2/19/2014. Lecture Outline Neutron Stars. Neutron Stars and Black Holes Neutron Stars. Units of Chapter 13.1 Neutron Stars Lecture Outline Chapter 13 Neutron Stars and After a Type I supernova, little or nothing remains of the original star. After a Type II supernova, part of the core may survive. It is

More information

Lecture 23 Stellar Evolution & Death (High Mass) November 21, 2018

Lecture 23 Stellar Evolution & Death (High Mass) November 21, 2018 Lecture 23 Stellar Evolution & Death (High Mass) November 21, 2018 1 2 High Mass Stars (M > 5 M ) Section 13.3 Bennett, The Essential Cosmic Perspective, 7 th ed. High mass stars have: More mass Greater

More information

Atomic Physics 3 ASTR 2110 Sarazin

Atomic Physics 3 ASTR 2110 Sarazin Atomic Physics 3 ASTR 2110 Sarazin Homework #5 Due Wednesday, October 4 due to fall break Test #1 Monday, October 9, 11-11:50 am Ruffner G006 (classroom) You may not consult the text, your notes, or any

More information

3/13/18. Things to do. Synchrotron Radiation. Today on Stellar Explosions

3/13/18. Things to do. Synchrotron Radiation. Today on Stellar Explosions ASTR 1040: Stars & Galaxies Prof. Juri Toomre TAs: Peri Johnson, Ryan Horton Lecture 17 Tues 13 Mar 2018 zeus.colorado.edu/astr1040-toomre Ring Nebula Today on Stellar Explosions Revisit Pulsars spinning

More information

First: Some Physics. Tides on the Earth. Lecture 11: Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes A2020 Prof. Tom Megeath. 1.

First: Some Physics. Tides on the Earth. Lecture 11: Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes A2020 Prof. Tom Megeath. 1. Lecture 11: Stellar Remnants: White Dwarfs, Neutron Stars, and Black Holes A2020 Prof. Tom Megeath First: Some Physics 1. Tides 2. Degeneracy Pressure Concept 1: How does gravity cause tides? R F tides

More information

Lecture Outlines. Chapter 22. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.

Lecture Outlines. Chapter 22. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc. Lecture Outlines Chapter 22 Astronomy Today 8th Edition Chaisson/McMillan Chapter 22 Neutron Stars and Black Holes Units of Chapter 22 22.1 Neutron Stars 22.2 Pulsars 22.3 Neutron-Star Binaries 22.4 Gamma-Ray

More information

Unstable Mass Transfer

Unstable Mass Transfer Unstable Mass Transfer When the mass ratios are large, or when the donor star has a deep convective layer (so R M-1/3), mass loss will occur on a dynamical timescale. The result will be common envelope

More information

Astronomy 100 Spring 2006 Lecture Questions Twelve Weeks Review

Astronomy 100 Spring 2006 Lecture Questions Twelve Weeks Review Astronomy 100 Spring 2006 Lecture Questions Twelve Weeks Review 16-1 Fusion in the Sun The solar corona has temperatures roughly the same as temperatures in the Sun's core, where nuclear fusion takes place.

More information

Gravity simplest. fusion

Gravity simplest. fusion Gravity simplest fusion The life of a star has a complex relationship with gravity: 1. Gravity is what brings the original dust together to make a star 2. Gravity wants to crush the star Gravity pulls

More information

Astronomy 110: SURVEY OF ASTRONOMY. 11. Dead Stars. 1. White Dwarfs and Supernovae. 2. Neutron Stars & Black Holes

Astronomy 110: SURVEY OF ASTRONOMY. 11. Dead Stars. 1. White Dwarfs and Supernovae. 2. Neutron Stars & Black Holes Astronomy 110: SURVEY OF ASTRONOMY 11. Dead Stars 1. White Dwarfs and Supernovae 2. Neutron Stars & Black Holes Low-mass stars fight gravity to a standstill by becoming white dwarfs degenerate spheres

More information

Physics HW Set 3 Spring 2015

Physics HW Set 3 Spring 2015 1) If the Sun were replaced by a one solar mass black hole 1) A) life here would be unchanged. B) we would still orbit it in a period of one year. C) all terrestrial planets would fall in immediately.

More information

Final States of a Star

Final States of a Star Pulsars Final States of a Star 1. White Dwarf If initial star mass < 8 MSun or so. (and remember: Maximum WD mass is 1.4 MSun, radius is about that of the Earth) 2. Neutron Star If initial mass > 8 MSun

More information

Today. Logistics. Visible vs. X-ray X. Synchrotron Radiation. Pulsars and Neutron Stars. ASTR 1040 Accel Astro: Stars & Galaxies

Today. Logistics. Visible vs. X-ray X. Synchrotron Radiation. Pulsars and Neutron Stars. ASTR 1040 Accel Astro: Stars & Galaxies ASTR 1040 Accel Astro: Stars & Galaxies Today Binary mass transfer Joys of nearest supernova: SN 1987A How mass transfer from binary companion can spin-up pulsar White dwarf supernovae from mass transfer

More information

Test #3 Next Tuesday, Nov. 8 Bring your UNM ID! Bring two number 2 pencils. Announcements. Review for test on Monday, Nov 7 at 3:25pm

Test #3 Next Tuesday, Nov. 8 Bring your UNM ID! Bring two number 2 pencils. Announcements. Review for test on Monday, Nov 7 at 3:25pm Test #3 Next Tuesday, Nov. 8 Bring your UNM ID! Bring two number 2 pencils Announcements Review for test on Monday, Nov 7 at 3:25pm Neutron Star - Black Hole merger Review for Test #3 Nov 8 Topics: Stars

More information

Chapter 18 Lecture. The Cosmic Perspective Seventh Edition. The Bizarre Stellar Graveyard Pearson Education, Inc.

Chapter 18 Lecture. The Cosmic Perspective Seventh Edition. The Bizarre Stellar Graveyard Pearson Education, Inc. Chapter 18 Lecture The Cosmic Perspective Seventh Edition The Bizarre Stellar Graveyard The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to

More information

White dwarfs are the remaining cores of dead stars. Electron degeneracy pressure supports them against the crush of gravity. The White Dwarf Limit

White dwarfs are the remaining cores of dead stars. Electron degeneracy pressure supports them against the crush of gravity. The White Dwarf Limit The Bizarre Stellar Graveyard Chapter 18 Lecture The Cosmic Perspective 18.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to a white dwarf in a close binary system? Seventh

More information

Death of Stars Part II Neutron Stars

Death of Stars Part II Neutron Stars Death of Stars Part II Neutron Stars 1 REMEMBER THIS!? 2 Guiding Questions 1. What led scientists to the idea of a neutron star? 2. What are pulsars, and how were they discovered? 3. How did astronomers

More information

MIDTERM #2. ASTR 101 General Astronomy: Stars & Galaxies. Can we detect BLACK HOLES? Black Holes in Binaries to the rescue. Black spot in the sky?

MIDTERM #2. ASTR 101 General Astronomy: Stars & Galaxies. Can we detect BLACK HOLES? Black Holes in Binaries to the rescue. Black spot in the sky? ASTR 101 General Astronomy: Stars & Galaxies Can we detect BLACK HOLES? NEXT Friday 04/03: MIDTERM #2 [Image by A. Hamilton] Black spot in the sky? Black Holes in Binaries to the rescue Black Holes in

More information

Special Relativity. Principles of Special Relativity: 1. The laws of physics are the same for all inertial observers.

Special Relativity. Principles of Special Relativity: 1. The laws of physics are the same for all inertial observers. Black Holes Special Relativity Principles of Special Relativity: 1. The laws of physics are the same for all inertial observers. 2. The speed of light is the same for all inertial observers regardless

More information

Astro 1050 Fri. Apr. 10, 2015

Astro 1050 Fri. Apr. 10, 2015 Astro 1050 Fri. Apr. 10, 2015 Today: Continue Ch. 13: Star Stuff Reading in Bennett: For Monday: Finish Chapter 13 Star Stuff Reminders: Ch. 12 HW now on Mastering Astronomy, due Monday. Ch. 13 will be

More information

Termination of Stars

Termination of Stars Termination of Stars Some Quantum Concepts Pauli Exclusion Principle: "Effectively limits the amount of certain kinds of stuff that can be crammed into a given space (particles with personal space ). When

More information

10/25/2010. Stars, Galaxies & the Universe Announcements. Stars, Galaxies & the Universe Lecture Outline. Reading Quiz #9 Wednesday (10/27)

10/25/2010. Stars, Galaxies & the Universe Announcements. Stars, Galaxies & the Universe Lecture Outline. Reading Quiz #9 Wednesday (10/27) Stars, Galaxies & the Universe Announcements Reading Quiz #9 Wednesday (10/27) HW#8 in ICON due Friday (10/29) by 5 pm - available Wednesday 1 Stars, Galaxies & the Universe Lecture Outline 1. Black Holes

More information

The Neutron Star Zoo. Stephen C.-Y. Ng ( 吳志勇 ) HKU

The Neutron Star Zoo. Stephen C.-Y. Ng ( 吳志勇 ) HKU The Neutron Star Zoo Stephen C.-Y. Ng ( 吳志勇 ) HKU Overview Introduction to neutron stars Different classes of neutron stars: Radio Pulsars MSPs Magnetars DINS CCOs Unification 6/12/2017 NAOC Stephen Ng

More information

Neutron Stars. Melissa Louie

Neutron Stars. Melissa Louie Neutron Stars Melissa Louie 11-08-10 Outline History, Formation, Properties Detection Pulsars Crab Nebula Pulsar Pulsar Timing Pulsars in Binary Systems Isolated Neutron Stars J185635-3754 Summary 2 The

More information

The Nature of Pulsars! Agenda for Ast 309N, Nov. 1. To See or Not to See (a Pulsar) The Slowing & Fading of Pulsars!

The Nature of Pulsars! Agenda for Ast 309N, Nov. 1. To See or Not to See (a Pulsar) The Slowing & Fading of Pulsars! Agenda for Ast 309N, Nov. 1 Quiz 7 Card 10/30 feedback More on pulsars and other neutron stars Begin: the saga of interacting binary systems Card: questions for review Reading: - Kaler, ch. 7 Wheeler,

More information

Life and Evolution of a Massive Star. M ~ 25 M Sun

Life and Evolution of a Massive Star. M ~ 25 M Sun Life and Evolution of a Massive Star M ~ 25 M Sun Birth in a Giant Molecular Cloud Main Sequence Post-Main Sequence Death The Main Sequence Stars burn H in their cores via the CNO cycle About 90% of a

More information

Active Galactic Nuclei-I. The paradigm

Active Galactic Nuclei-I. The paradigm Active Galactic Nuclei-I The paradigm An accretion disk around a supermassive black hole M. Almudena Prieto, July 2007, Unv. Nacional de Bogota Centers of galaxies Centers of galaxies are the most powerful

More information

Components of Galaxies Stars What Properties of Stars are Important for Understanding Galaxies?

Components of Galaxies Stars What Properties of Stars are Important for Understanding Galaxies? Components of Galaxies Stars What Properties of Stars are Important for Understanding Galaxies? Temperature Determines the λ range over which the radiation is emitted Chemical Composition metallicities

More information

Neutron Stars, Black Holes, Pulsars and More

Neutron Stars, Black Holes, Pulsars and More Neutron Stars, Black Holes, Pulsars and More October 30, 2002 1) Star Clusters 2) Type II Supernova 3) Neutron Stars 4) Black Holes 5) More Gravity Announcements Extra Credit there is an extra credit assignment

More information

ASTR 200 : Lecture 20. Neutron stars

ASTR 200 : Lecture 20. Neutron stars ASTR 200 : Lecture 20 Neutron stars 1 Equation of state: Degenerate matter We saw that electrons exert a `quantum mechanical' pressure. This is because they are 'fermions' and are not allowed to occupy

More information

The Death of Stars. Today s Lecture: Post main-sequence (Chapter 13, pages ) How stars explode: supernovae! White dwarfs Neutron stars

The Death of Stars. Today s Lecture: Post main-sequence (Chapter 13, pages ) How stars explode: supernovae! White dwarfs Neutron stars The Death of Stars Today s Lecture: Post main-sequence (Chapter 13, pages 296-323) How stars explode: supernovae! White dwarfs Neutron stars White dwarfs Roughly the size of the Earth with the mass of

More information

Protostars on the HR Diagram. Lifetimes of Stars. Lifetimes of Stars: Example. Pressure-Temperature Thermostat. Hydrostatic Equilibrium

Protostars on the HR Diagram. Lifetimes of Stars. Lifetimes of Stars: Example. Pressure-Temperature Thermostat. Hydrostatic Equilibrium Protostars on the HR Diagram Once a protostar is hot enough to start, it can blow away the surrounding gas Then it is visible: crosses the on the HR diagram The more the cloud, the it will form stars Lifetimes

More information

Lecture 13: Binary evolution

Lecture 13: Binary evolution Lecture 13: Binary evolution Senior Astrophysics 2017-04-12 Senior Astrophysics Lecture 13: Binary evolution 2017-04-12 1 / 37 Outline 1 Conservative mass transfer 2 Non-conservative mass transfer 3 Cataclysmic

More information

High Mass Stars and then Stellar Graveyard 7/16/09. Astronomy 101

High Mass Stars and then Stellar Graveyard 7/16/09. Astronomy 101 High Mass Stars and then Stellar Graveyard 7/16/09 Astronomy 101 Astronomy Picture of the Day Astronomy 101 Something Cool Betelgeuse Astronomy 101 Outline for Today Astronomy Picture of the Day Something

More information

Astronomy 104: Second Exam

Astronomy 104: Second Exam Astronomy 104: Second Exam Stephen Lepp October 29, 2014 Each question is worth 2 points. Write your name on this exam and on the scantron. Short Answer A The Sun is powered by converting hydrogen to what?

More information

Protostars evolve into main-sequence stars

Protostars evolve into main-sequence stars Understanding how stars evolve requires both observation and ideas from physics The Lives of Stars Because stars shine by thermonuclear reactions, they have a finite life span That is, they fuse lighter

More information

Mass loss from stars

Mass loss from stars Mass loss from stars Can significantly affect a star s evolution, since the mass is such a critical parameter (e.g., L ~ M 4 ) Material ejected into interstellar medium (ISM) may be nuclear-processed:

More information

Dr G. I. Ogilvie Lent Term 2005 INTRODUCTION

Dr G. I. Ogilvie Lent Term 2005 INTRODUCTION Accretion Discs Mathematical Tripos, Part III Dr G. I. Ogilvie Lent Term 2005 INTRODUCTION 0.1. Accretion If a particle of mass m falls from infinity and comes to rest on the surface of a star of mass

More information

Pulsars - a new tool for astronomy and physics

Pulsars - a new tool for astronomy and physics 1 Reading: Chapter 24, Sect. 24.5-24.6; Chap. 20, Chap. 25, Sec. 25.1 Exam 2: Thursday, March 22; essay question given on Tuesday, March 20 Last time:death of massive stars - supernovae & neutron stars

More information

Stellar-Mass Black Holes and Pulsars

Stellar-Mass Black Holes and Pulsars Stellar-Mass Black Holes and Pulsars Anthony Rushton Work group 2 leader (ESO ALMA fellow) 2010-06-24 Overview of Work Group 2 Stellar-mass black holes and pulsars Two work group leaders: Anthony Rushton

More information

Cosmology - Redshift and Radiation ASTR 2120 Sarazin

Cosmology - Redshift and Radiation ASTR 2120 Sarazin Cosmology - Redshift and Radiation ASTR 2120 Sarazin Test #1 Monday, February 26, 11-11:50 am ASTR 265 (classroom) Bring pencils, paper, calculator You may not consult the text, your notes, or any other

More information

Stellar remnants II. Neutron Stars 10/18/2010. (progenitor star 1.4 < M< 3 Msun) Stars, Galaxies & the Universe Announcements

Stellar remnants II. Neutron Stars 10/18/2010. (progenitor star 1.4 < M< 3 Msun) Stars, Galaxies & the Universe Announcements Stars, Galaxies & the Universe Announcements Exam #2 on Wednesday Review sheet and study guide posted by Thursday Use office hours and Astronomy Tutorial hours Covers material since Exam #1 (plus background

More information

For instance, due to the solar wind, the Sun will lose about 0.1% of its mass over its main sequence existence.

For instance, due to the solar wind, the Sun will lose about 0.1% of its mass over its main sequence existence. 7/7 For instance, due to the solar wind, the Sun will lose about 0.1% of its mass over its main sequence existence. Once a star evolves off the main sequence, its mass changes more drastically. Some stars

More information

10/26/ Star Birth. Chapter 13: Star Stuff. How do stars form? Star-Forming Clouds. Mass of a Star-Forming Cloud. Gravity Versus Pressure

10/26/ Star Birth. Chapter 13: Star Stuff. How do stars form? Star-Forming Clouds. Mass of a Star-Forming Cloud. Gravity Versus Pressure 10/26/16 Lecture Outline 13.1 Star Birth Chapter 13: Star Stuff How do stars form? Our goals for learning: How do stars form? How massive are newborn stars? Star-Forming Clouds Stars form in dark clouds

More information

Astronomy Notes Chapter 13.notebook. April 11, 2014

Astronomy Notes Chapter 13.notebook. April 11, 2014 All stars begin life in a similar way the only difference is in the rate at which they move through the various stages (depends on the star's mass). A star's fate also depends on its mass: 1) Low Mass

More information

NEUTRON STARS, GAMMA RAY BURSTS, and BLACK HOLES (chap. 22 in textbook)

NEUTRON STARS, GAMMA RAY BURSTS, and BLACK HOLES (chap. 22 in textbook) NEUTRON STARS, GAMMA RAY BURSTS, and BLACK HOLES (chap. 22 in textbook) Neutron Stars For carbon detonation SN probably no remnant For core-collapse SN remnant is a neutron-degenerate core neutron star

More information

29:50 Stars, Galaxies, and the Universe Second Hour Exam November 10, 2010 Form A

29:50 Stars, Galaxies, and the Universe Second Hour Exam November 10, 2010 Form A 29:50 Stars, Galaxies, and the Universe Second Hour Exam November 10, 2010 Form A There are 20 questions (Note: There will be 32 on the real thing). Read each question and all of the choices before choosing.

More information

Quasars, Pulsars, Gamma- Ray Bursts! Oh, my! Collapsars, magnetars, X- ray pulsars, γ-ray pulsars, millisecond radio pulsars...

Quasars, Pulsars, Gamma- Ray Bursts! Oh, my! Collapsars, magnetars, X- ray pulsars, γ-ray pulsars, millisecond radio pulsars... Quasars, Pulsars, Gamma- Ray Bursts! Oh, my! Collapsars, magnetars, X- ray pulsars, γ-ray pulsars, millisecond radio pulsars... Giacconi et al. (1962) Rocket carried 3 Geiger counters to 225km - one counter

More information

Objectives. HR Diagram

Objectives. HR Diagram Objectives HR Diagram Questions from Yesterday Centripetal Force perpendicular to the rotation axis Acts to slow down collapse Strongest 90 deg from rotation axis Particles with an angle < 90 feel the

More information

AST-1002 Section 0459 Review for Final Exam Please do not forget about doing the evaluation!

AST-1002 Section 0459 Review for Final Exam Please do not forget about doing the evaluation! AST-1002 Section 0459 Review for Final Exam Please do not forget about doing the evaluation! Bring pencil #2 with eraser No use of calculator or any electronic device during the exam We provide the scantrons

More information

Relativistic Astrophysics Neutron Stars, Black Holes & Grav. W. ... A brief description of the course

Relativistic Astrophysics Neutron Stars, Black Holes & Grav. W. ... A brief description of the course Relativistic Astrophysics Neutron Stars, Black Holes & Grav. Waves... A brief description of the course May 2, 2009 Structure of the Course Introduction to General Theory of Relativity (2-3 weeks) Gravitational

More information

Neutron Stars. are as small as a city (~10 km) But as massive as the Sun!

Neutron Stars. are as small as a city (~10 km) But as massive as the Sun! Neutron Stars are as small as a city (~10 km) But as massive as the Sun! Extra-Terrestrial Mystery...! In 1967, graduate student Jocelyn Bell helped build a radio telescope in England.! She found a source

More information