1. LECTURE 18, NOVEMBER 2, 2010 ASTR 101, SECTION 2 INSTRUCTOR, JACK BRANDT jcbrandt@unm.edu 1ASTR 101-3, FALL 2010

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7. a) its core begins fusing iron. b) its supply of hydrogen is used up. c) the carbon core detonates, and it explodes as a Type I supernova. d) helium builds up in the core, while the hydrogen-burning shell expands. e) the core loses all of its neutrinos, so all fusion ceases. Question 3 The Sun will evolve away from the main sequence when

8. a) its core begins fusing iron. b) its supply of hydrogen is used up. c) the carbon core detonates, and it explodes as a Type I supernova. d) helium builds up in the core, while the hydrogen-burning shell expands. e) the core loses all of its neutrinos, so all fusion ceases. Question 3 The Sun will evolve away from the main sequence when When the Sun’s core becomes unstable and contracts, additional H fusion generates extra pressure, and the star will swell into a red giant.

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15. a) red giants. b) pulsars. c) black holes. d) white dwarfs. e) red dwarfs. Question 1 Stars like our Sun will end their lives as

16. a) red giants. b) pulsars. c) black holes. d) white dwarfs. e) red dwarfs. Question 1 Stars like our Sun will end their lives as Low-mass stars eventually swell into red giants, and their cores later contract into white dwarfs.

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19. a) an asteroid. b) a planet the size of Earth. c) a planet the size of Jupiter. d) an object the size of the Moon. e) an object the size of a sugar cube. Question 8 In a white dwarf, the mass of the Sun is packed into the volume of

20. a) an asteroid. b) a planet the size of Earth. c) a planet the size of Jupiter. d) an object the size of the Moon. e) an object the size of a sugar cube. Question 8 In a white dwarf, the mass of the Sun is packed into the volume of The density of a white dwarf is about a million times greater than normal solid matter.

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25. a) mass transfer onto a white dwarf in a binary star system. b) repeated helium fusion flashes in red giants. c) rapid collapse of a protostar into a massive O star. d) the explosion of a low-mass star. e) the birth of a massive star in a new cluster. Question 11 A nova involves

26. a) mass transfer onto a white dwarf in a binary star system. b) repeated helium fusion flashes in red giants. c) rapid collapse of a protostar into a massive O star. d) the explosion of a low-mass star. e) the birth of a massive star in a new cluster. Question 11 A nova involves Sudden, rapid fusion of new fuel dumped onto a white dwarf causes the star to flare up, and for a short time become much brighter.

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32. a) the number of main sequence stars. b) the ratio of giants to supergiants. c) the luminosity of stars at the turnoff point. d) the number of white dwarfs. e) supernova explosions. Question 6 Astronomers determine the age of star clusters by observing

33. a) the number of main sequence stars. b) the ratio of giants to supergiants. c) the luminosity of stars at the turnoff point. d) the number of white dwarfs. e) supernova explosions. Question 6 Astronomers determine the age of star clusters by observing The H–R diagram of a cluster can indicate its approximate age. Turnoff point from the main sequence

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37. a) as a protostar. b) as a red giant. c) as a main-sequence star. d) as a white dwarf. e) evolving from type O to type M. Question 10 A star will spend most of its “shining” lifetime

38. a) as a protostar. b) as a red giant. c) as a main-sequence star. d) as a white dwarf. e) evolving from type O to type M. Question 10 A star will spend most of its “shining” lifetime In the main-sequence stage, hydrogen fuses to helium. Pressure from light and heat pushing out balances gravitational pressure pushing inward.

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