Charles Hakes Fort Lewis College1

Charles Hakes Fort Lewis College2

Charles Hakes Fort Lewis College3 “Dead” Stars

Charles Hakes Fort Lewis College4 Outline Test 3 Friday Lab Notes Dead (?) Stars Review (?)

Charles Hakes Fort Lewis College5 Test 3 Review Spectroscopy (Wein, Stefan) and Doppler Shift The Sun (structure, fusion) Magnitude Parallax Interstellar Medium Stellar Evolution Dead Stars

Charles Hakes Fort Lewis College6 Lab Notes Constellation presentation this week Telescope lab Star identification lab? Observatory Field Trip? Parallax

Charles Hakes Fort Lewis College7 More Precisely 12-1 The Cycle of Stellar Evolution

Charles Hakes Fort Lewis College8 Supernovae On-line images Supernova in M Supernova in NGC Supernova in NGC Supernova in NGC Supernova in NGC Supernova in NGC

Charles Hakes Fort Lewis College9 Chapter 13 What is left after a Supernova?

Charles Hakes Fort Lewis College10 Figure Supernova Remnants

Charles Hakes Fort Lewis College11 Figure 13.1 Neutron Star - from a type II Supernova typically ~20 km diameter mass > M sun thimbleful would weigh 10 8 tons rotate very quickly have very strong magnetic fields.

Charles Hakes Fort Lewis College12 Figure 13.2 Pulsar Radiation The first observed neutron star was a pulsar Neutron stars rotate VERY quickly.

Charles Hakes Fort Lewis College13 Figure 13.3 Pulsar Model l lighthouse model - if the beam sweeps past the Earth, we see a pulse.

Charles Hakes Fort Lewis College14 At a distance of 1 A.U., which would have the greatest gravitational force? A) A 1 solar mass main sequence star B) A 1 solar mass white dwarf C) A 1 solar mass neutron star D) They all have the same force.

Charles Hakes Fort Lewis College15 At a distance of 1 A.U., which would have the greatest gravitational force? A) A 1 solar mass main sequence star B) A 1 solar mass white dwarf C) A 1 solar mass neutron star D) They all have the same force.

Charles Hakes Fort Lewis College16 At the surface of the object, which would have the greatest gravitational force? A) A 1 solar mass main sequence star B) A 1 solar mass white dwarf C) A 1 solar mass neutron star D) They all have the same force.

Charles Hakes Fort Lewis College17 At the surface of the object, which would have the greatest gravitational force? A) A 1 solar mass main sequence star B) A 1 solar mass white dwarf C) A 1 solar mass neutron star D) They all have the same force.

Charles Hakes Fort Lewis College18 A neutron star cannot be more than 3 M sun.

Charles Hakes Fort Lewis College19 A neutron star cannot be more than 3 M sun. Surface gravity will become so great that not even light can escape. (Escape velocity > c)

Charles Hakes Fort Lewis College20 A neutron star cannot be more than 3 M sun. Surface gravity will become so great that not even light can escape. (Escape velocity > c) Stars that began with > 25 M sun will probably become black holes.

Charles Hakes Fort Lewis College21 Black Holes Can black holes be made of things other than neutron stars? Any object of any mass has a radius that if it is compressed below that radius, light cannot escape. This is called the Schwarzschild radius. r S = 3km x M(solar masses)

Charles Hakes Fort Lewis College22 Black Holes Example Schwarzschild radii : Sun = 3km 3M solar Core = 9km Jupiter = 3m

Charles Hakes Fort Lewis College23 Black Holes Exercise - calculate the size required to compress a 70 kg person to make a black hole. recall: r S = 3km x M(solar masses)

Charles Hakes Fort Lewis College24 Black Holes Example Schwarzschild radii : Sun = 3km 3M solar Core = 9km Jupiter = 3m Earth = ~1cm Person = ~1x m M observable universe = ~r observable universe

Charles Hakes Fort Lewis College25 If the Sun were suddenly replaced by a one solar mass black hole: A) we would immediately escape into deep space, driven out by its radiation. B) our clocks would all stop. C) life here would be unchanged. D) we would still orbit it in a period of one year. E) all terrestrial planets would fall in immediately.

Charles Hakes Fort Lewis College26 If the Sun were suddenly replaced by a one solar mass black hole: A) we would immediately escape into deep space, driven out by its radiation. B) our clocks would all stop. C) life here would be unchanged. D) we would still orbit it in a period of one year. E) all terrestrial planets would fall in immediately.

Charles Hakes Fort Lewis College27 Practice Problem You observe a binary star system where the two stars are exactly the same temperature. The diameter of one star is 1.2 times the diameter of the second star. How many times more energy is emitted by the brighter star?

Charles Hakes Fort Lewis College28 Practice Problem You observe a binary star system where the two stars are exactly the same temperature. The diameter of one star is 1.2 times the diameter of the second star. How many times more energy is emitted by the brighter star? A x B. 1.2x C. 1.44x D. 2x

Charles Hakes Fort Lewis College29 Practice Problem You observe a binary star system where the two stars are exactly the same size. One star is 5500 K. The other star is 6100 K. How many times more energy is emitted by the brighter star?

Charles Hakes Fort Lewis College30 Practice Problem You observe a binary star system where the two stars are exactly the same size. One star is 5500 K. The other star is 6100 K. How many times more energy is emitted by the brighter star? A. 1.11x B. 1.23x C. 1.51x D. 600x

Charles Hakes Fort Lewis College31 Review Questions

Charles Hakes Fort Lewis College32 An ordinary star becomes a Red Giant when: A) A white dwarf companion star goes nova B) There is no Hydrogen remaining in the star C) Nutrino oscillations drive the outer layers D) The core becomes almost entirely Helium

Charles Hakes Fort Lewis College33 An ordinary star becomes a Red Giant when: A) A white dwarf companion star goes nova B) There is no Hydrogen remaining in the star C) Nutrino oscillations drive the outer layers D) The core becomes almost entirely Helium

Charles Hakes Fort Lewis College34 A main sequence star of 19 solar masses will eventually be a: A) A brown dwarf B) A white dwarf C) A type I supernova D) A type II supernova

Charles Hakes Fort Lewis College35 A main sequence star of 19 solar masses will eventually be a: A) A brown dwarf B) A white dwarf C) A type I supernova D) A type II supernova

Charles Hakes Fort Lewis College36 A supernova is observed with very little H in the spectrum. It is most likely a: A) type I B) type II C) type III D) not enough information

Charles Hakes Fort Lewis College37 A supernova is observed with very little H in the spectrum. It is most likely a: A) type I B) type II C) type III D) not enough information

Charles Hakes Fort Lewis College38 A source of light is approaching us at 3,000 km/s. All its waves are: A) Red shifted by 1% B) Blue shifted by 1% C) Not affected, as c is constant in all reference frames. D) Red shifted out of the visible into the infrared E) Blue shifted out of the visible into the ultraviolet

Charles Hakes Fort Lewis College39 A source of light is approaching us at 3,000 km/s. All its waves are: A) Red shifted by 1% B) Blue shifted by 1% C) Not affected, as c is constant in all reference frames. D) Red shifted out of the visible into the infrared E) Blue shifted out of the visible into the ultraviolet

Charles Hakes Fort Lewis College40 How could you determine the temperature of the photosphere of the Sun? A) only direct spacecraft measurement B) Newton’s Law C) Stefan’s Law D) Wein’s law

Charles Hakes Fort Lewis College41 How could you determine the temperature of the photosphere of the Sun? A) only direct spacecraft measurement B) Newton’s Law C) Stefan’s Law D) Wein’s law

Charles Hakes Fort Lewis College42 If a star has a parallax of 0.05”, then its distance must be A) 5 light years. B) 5 parsecs C) 20 light years. D) 20 parsecs. E) 200 parsecs

Charles Hakes Fort Lewis College43 If a star has a parallax of 0.05”, then its distance must be A) 5 light years. B) 5 parsecs C) 20 light years. D) 20 parsecs. E) 200 parsecs

Charles Hakes Fort Lewis College44 Assume your naked eye limiting magnitude is 4. With a 70mm diameter telescope (100x area of your pupil) which object would be barely visible? A) Seventh magnitude Titan, Saturn’s largest moon. B) Eighth magnitude Uranus. C) Ninth magnitude Barnard’s Star D) Eleventh magnitude Tethys, another Saturn moon E) Thirteenth magnitude Pluto

Charles Hakes Fort Lewis College45 Assume your naked eye limiting magnitude is 4. With a 70mm diameter telescope (100x area of your pupil) which object would be barely visible? A) Seventh magnitude Titan, Saturn’s largest moon. B) Eighth magnitude Uranus. C) Ninth magnitude Barnard’s Star D) Eleventh magnitude Tethys, another Saturn moon E) Thirteenth magnitude Pluto

Charles Hakes Fort Lewis College46 On the H-R diagram, red supergiants like Betelguese lie: A) top right B) top left C) about the middle D) lower left E) on the coolest portion of the main sequence

Charles Hakes Fort Lewis College47 On the H-R diagram, red supergiants like Betelguese lie: A) top right B) top left C) about the middle D) lower left E) on the coolest portion of the main sequence

Charles Hakes Fort Lewis College48 From inside out, which is the correct order? A) core, convective zone, radiative zone B) photosphere, radiative zone, corona C) radiative zone, convective zone, chromosphere D) core, chromosphere, photosphere E) convective zone, radiative zone, granulation

Charles Hakes Fort Lewis College49 From inside out, which is the correct order? A) core, convective zone, radiative zone B) photosphere, radiative zone, corona C) radiative zone, convective zone, chromosphere D) core, chromosphere, photosphere E) convective zone, radiative zone, granulation

Charles Hakes Fort Lewis College50 If Vega is apparent magnitude zero, and Deneb first magnitude, then A) Vega is about 100x brighter than Deneb.. B) Deneb is one magnitude brighter than Vega. C) Vega appears 2.5x brighter than Deneb. D) Deneb must be a main sequence star, and Vega a giant. E) Vega must be 2.5x more luminous than Deneb.

Charles Hakes Fort Lewis College51 If Vega is apparent magnitude zero, and Deneb first magnitude, then A) Vega is about 100x brighter than Deneb.. B) Deneb is one magnitude brighter than Vega. C) Vega appears 2.5x brighter than Deneb. D) Deneb must be a main sequence star, and Vega a giant. E) Vega must be 2.5x more luminous than Deneb.

Charles Hakes Fort Lewis College52 Three Minute Paper Write 1-3 sentences. What was the most important thing you learned today? What questions do you still have about today’s topics?