1. White Dwarf If initial star mass < 8 M Sun or so. (and remember: Maximum WD mass is 1.4 M Sun, radius is about that of the Earth) 2. Neutron Star If.

Slides:



Advertisements
Similar presentations
White Dwarf Stars Low mass stars are unable to reach high enough temperatures to ignite elements heavier than carbon in their core become white dwarfs.
Advertisements

© 2010 Pearson Education, Inc. Chapter 18 The Bizarre Stellar Graveyard.
1 Stellar Remnants White Dwarfs, Neutron Stars & Black Holes These objects normally emit light only due to their very high temperatures. Normally nuclear.
Lecture 26: The Bizarre Stellar Graveyard: White Dwarfs and Neutron Stars.
Supernovae and nucleosynthesis of elements > Fe Death of low-mass star: White Dwarf White dwarfs are the remaining cores once fusion stops Electron degeneracy.
9A Black Holes and Neutron Stars Dead Stars Copyright – A. Hobart.
Chapter 18 Lecture The Cosmic Perspective Seventh Edition © 2014 Pearson Education, Inc. The Bizarre Stellar Graveyard.
Chapter 13 The Bizarre Stellar Graveyard
Copyright © 2009 Pearson Education, Inc. Chapter 13 The Bizarre Stellar Graveyard.
YSS - Intro. to Observational Astrophysics (ASTR 205). Class #10 The Bizarre Stellar Graveyard (Chapter 13) Professor: José Maza June 20, 2011 Professor:
The Radio Afterglow produced by the Giant Flare from the Magnetar SGR Greg Taylor (NRAO/KIPAC) with: J. Granot, B. M. Gaensler, C. Kouveliotou,
Ryo Yamazaki (Osaka University, Japan) With K. Ioka, F. Takahara, and N. Shibazaki.
Stellar Deaths II Neutron Stars and Black Holes 17.
Neutron Stars and Black Holes Please press “1” to test your transmitter.
1. black hole - region of space where the pull of gravity is so great that even light cannot escape. Possible end of a very massive star.
Mass transfer in a binary system
Neutron Stars and Black Holes
Neutron Stars and Black Holes
 When found in stars between 8 and 25x M sun, what happens to the core?  Cores are stopped by the outer layers of the star  Cores recontract and remain.
Neutron Stars and Black Holes Chapter 14. The preceding chapters have traced the story of stars from their birth as clouds of gas in the interstellar.
(Recalling the Death of a High-Mass Star…). Neutron stars, although they have 1–3 solar masses, are so dense that they are very small. This image.
Life and Evolution of a Massive Star M ~ 25 M Sun.
White Dwarfs and Neutron Stars White dwarfs –Degenerate gases –Mass versus radius relation Neutron stars –Mass versus radius relation –Pulsars, magnetars,
Supernova and Neutron Stars
10 Black Holes and Neutron Stars Dead Stars Copyright – A. Hobart.
Neutron stars - Chapter Neutron stars The remains of cores of some massive stars that have become supernovae. Cores are a degenerate gas of mostly.
13 Black Holes and Neutron Stars Dead Stars Copyright – A. Hobart.
1. White Dwarf If initial star mass < 8 M Sun or so. (and remember: Maximum WD mass is 1.4 M Sun, radius is about that of the Earth) 2. Neutron Star If.
This set of slides This set of slides covers the supernova of white dwarf stars and the late-in-life evolution and death of massive stars, stars > 8 solar.
The Stellar Graveyard.
Question The pressure that prevents the gravitational collapse of white dwarfs is a result of ______.  A) Conservation of energy  B) Conservation of.
Outline ● Novae (detonations on the surface of a star) ● Supernovae (detonations of a star) ● The Mystery of Gamma Ray Bursts (GRBs) ● Sifting through.
Chapter 10 – part 3 - Neutron stars and Black Holes Neutron stars.
Nebulas are made up of gas left behind by stars forming or exploding There are different classes of Nebulas The classes are: Reflection Nebulae, Emission.
Clicker Question: The age of a cluster can be found by: A: Looking at its velocity through the galaxy. B: Determining the turnoff point from the main sequence.
Neutron Stars and Black Holes Chapter 14. Formation of Neutron Stars Compact objects more massive than the Chandrasekhar Limit (1.4 M sun ) collapse beyond.
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.
1 Stellar Remnants White Dwarfs, Neutron Stars & Black Holes These objects normally emit light only due to their very high temperatures. Normally nuclear.
Neutron Stars Pulsars. Neutron Stars In 1967, it was believed (by some) that the first intelligent signal from outer space had been discovered. A graduate.
Remnant of a Type II supernova explosion Iron core collapses until neutrons are squeezed tightly together During the explosion core remains intact, outer.
Plasma universe Fluctuations in the primordial plasma are observed in the cosmic microwave background ESA Planck satellite to be launched in 2007 Data.
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.
Death of Stars III Physics 113 Goderya Chapter(s): 14 Learning Outcomes:
Historical SN and their properties Total energy released ~10 54 erg in a few hours.
Lecture Outline Chapter 14: The Bizarre Stellar Graveyard © 2015 Pearson Education, Inc.
YSS - Intro. to Observational Astrophysics (ASTR 205). Class #10 The Bizarre Stellar Graveyard (Chapter 13) Professor: José Maza July 3, 2012 Professor:
Death of Stars II Physics 113 Goderya Chapter(s): 14
Goal: To understand special stars. Objectives: 1)To learn about Neutron Stars 2)To learn about Pulsars 3)To understand Stars that erupt.
I.Death of Stars White Dwarfs Neutron Stars Black Holes II.Cycle of Birth and Death of Stars (borrowed in part from Ch. 14) Outline of Chapter 13 Death.
Chapter 13 The Bizarre Stellar Graveyard White Dwarfs Our goals for learning: What is a white dwarf? What can happen to a white dwarf in a close.
Gamma-Ray Bursts. Short (sub-second to minutes) flashes of gamma- rays, for ~ 30 years not associated with any counterparts in other wavelength bands.
White dwarfs cool off and grow dimmer with time. The White Dwarf Limit A white dwarf cannot be more massive than 1.4M Sun, the white dwarf limit (or Chandrasekhar.
Chapter 13 Neutron Stars and Black Holes. Optical, Infrared and X-ray Image of Cassiopeia A.
Announcements Exam 3 is scheduled for Wednesday April 8. Will be pushed back to Monday April 13 Tentatively will cover the rest of Chapter 4, all of Chapters.
Copyright © 2010 Pearson Education, Inc. Clicker Questions Chapter 13 Neutron Stars and Black Holes.
Astronomy: A Beginner’s Guide to the Universe Seventh Edition © 2013 Pearson Education, Inc. Neutron Stars and Black Holes Chapter 13 Clickers.
Chapter 10 The Bizarre Stellar Graveyard. The Products of Star Death White Dwarfs Neutron Stars Black Holes.
© 2010 Pearson Education, Inc. The Bizarre Stellar Graveyard.
Units to cover 66, 67,68. Homework 9 Unit 64, problems 4, 5, 9 Unit 65, problems 4, 10 Unit 66, problem 6.
Gamma-Ray Bursts Please press “1” to test your transmitter.
© 2017 Pearson Education, Inc.
Black holes, neutron stars and binary star systems
Neutron Stars and Black Holes
Ch Exploding Stars & Black Holes
Neutron Stars In a type II supernova the shock wave does not start at the very center of the collapsing core. After the explosion, the inner ball of neutrons.
Evolution of the Solar System
The Death of a Star.
Final states of a star: 1. White Dwarf
The Death of a Star.
Presentation transcript:

1. White Dwarf If initial star mass < 8 M Sun or so. (and remember: Maximum WD mass is 1.4 M Sun, radius is about that of the Earth) 2. Neutron Star If initial mass > 8 M Sun and < 25 M Sun. 3. Black Hole If initial mass > 25 M Sun. Final States of a Star

Pulsars Discovery of LGM1 by Jocelyn Bell and Tony Hewish (Cambridge) in Nobel Prize to Hewish in Pulse periods observed from sec to 10 seconds - DEMO Explanation: "beamed" radiation from rapidly spinning neutron star. Usually neutron stars are pulsars for 10 7 years after supernova.

The Crab Pulsar

Neutron Stars Leftover core from Type II supernova - a tightly packed ball of neutrons. Diameter: 20 km only! Mass: (?) M Sun Density: g / cm 3 ! Surface gravity: higher Escape velocity: 0.6c Rotation rate: few to many times per second!!! Magnetic field: x Earth's! A neutron star over the Sandias?

An Isolated Neutron Star T ~ 2 million K Size ~ 30 km

The Lighthouse model of a pulsar

Pulsars are incredibly accurate clocks! Example: period of the first discovered "millisecond pulsar" is: P = sec It is slowing down at a rate of x sec/sec The slowing-down rate is slowing down at a rate of: 0.98 x /sec

Multi-wavelength observations of Pulsars

Pulsar Exotica Binary pulsars: two pulsars in orbit around each other. Einstein predicted that binary orbits should "decay", i.e. the masses would spiral in towards each other, losing energy through "gravitational radiation". Confirmed by binary pulsar. year Curve: prediction of decaying orbit. Points: measurements. Planets around pulsars: A pulsar was found in 1992 to have three planets! Masses about 3 M Earth, 1 M Earth, and 1 M Moon ! Millisecond pulsars: periods of 1 to a few msec. Probably accreted matter from a binary companion that made it spin faster. Gamma-ray Bursts: some pulsars produce bursts of gamma-rays, called Soft Gamma-Ray Repeaters or SGRs

Time history of the 4 confirmed SGRs: Woods & Thompson 2004

Soft Gamma-Ray Repeaters X-ray image " E iso ~ a few10 44 erg in gamma-rays Where does this energy come from? - Accretion? No sign of a disk - Rotation? Not enough energy available - Magnetic fields? Yes

Clicker Question: What is our basic model for a pulsar? A: a rotating white dwarf B: a rotating neutron star C: a rotating black hole D: an oscillating star

Clicker Question: What is the diameter of a 2 M sun neutron star? A: 20 km B: 2000 km C: 14,000 km (size of the Earth) D: 1,400,000 km (size of the Sun)

Clicker Question: Which of the following is true about a binary pulsar system? A: It will last forever. B: They can only be found in star forming regions C: The total mass of the two pulsars must be more than 10 solar masses. D: Each of the pulsars was produced by a massive star that exploded in a Supernova event.

Giant Flares from SGRs " Initial spike:  t ~ 0.3 s, E iso ~ a few10 44 erg – hard spectrum – ~ ms rise time " Pulsating tail – Lasts a few min. – Modulated at the NS rotation period – Softer spectrum " Only 2 previous events ever recorded: in 1979 (SGR in LMC) & 1998 (SGR ) The 1998 August 27 giant flare from SGR

The 2004 Dec. 27 Giant Flare RHESSI Swift " was ~ 5 o from the sun  It’s distance ≈ 15 kpc " E iso ~ erg (Palmer et al. 2005) (Hurley et al. 2005)

Rise time: < 1 ms Swift (Palmer et al. 2005)

Sudden Ionospheric Disturbance (SID) Cambell et al Washington, USA to Alberta, CA

The Fossil Record is Marked by Mass Extinction Events Extinction Genus loss End Ordovician 60% End Devonian 57% End Permian 82% End Triassic 53% End Cretaceous 47% From Solé & Newman 2002

Effects of a nearby GRB on Earth Melott et al. 2004

Raphaeli 2001 B ~ 0.3  G Gaensler et al 2005

Growth of the Radio Afterglow VLA 8.5 GHz Size at t+7 days cm (1000 AU) Velocity to t + 30 days ~ 0.8 c Decrease in v exp

Image Evolution VLA 8.5 GHz E ~ 10^45 ergs One-sided (anisotropic) outflow Taylor et al 2005

Radio Light Curves bump (Gaensler et al. 2005; Gelfand et al. 2005)

From Cameron et al Radio Afterglow has a Steep Spectrum ~ -0.6 at t+7 days down to 220 MHz Flux > 1 Jy at early times and low frequencies.

Adapted from Duncan and Thompson 1992

Clicker Question: The energy source for the repeated gamma-ray bursts (SGRs) from some neutron stars is what? A: fusion of hydrogen on the surface B: energy released by material accreting onto the surface. C: the result of reconfigurations of the strong magnetic fields D: changes in the rotation rate of the neutron star.

Clicker Question: What happens to a neutron star that acquires a mass of more than 3 M sun ? A: It will split into two or more neutron stars B: It will explode and blow itself to bits C: It will collapse to form a black hole D: It will produce a type II supernova, leaving a single neutron star.

NS Merger Model for short GRBs Mean redshift ~ 0.25 for short hard bursts (SHB) No supernova association expected SHBs often found at outskirts of galaxy (implies large peculiar velocities) SHBs found in - Elliptical galaxies - galaxies with low star formation rates

Neutron Star merger

WR104 - Looking Down the Barrel of a GRB system 8000 lt-years from us