The section of the H–R diagram where the Cepheid variables reside is the a. birth line. b. zero-age main sequence. c. instability strip. d. horizontal branch. e. white dwarf region.
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a. |
birth line.
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b. |
zero-age main sequence.
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c. |
instability strip.
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d. |
horizontal branch.
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e. |
white dwarf region.
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- A helium flash occurs a. because helium is very explosive and cannot be controlled when the nuclear reactions occur. b. because degenerate electrons in the core do not allow the core to expand as it heats up. c. in Cepheid variables. d. in stars with masses less than 0.4 M. e. under none of the above conditions.Once carbon builds up in the Sun's core, astronomers expect our Sun to first become a red giant, then a .. Select one: A. neutron star B. red dwarf C. planetary nebula D. black hole E. pulsar1. A star with an original mass of 9MSun undergoes an active period where it experiences mass loss via a super-wind over 1.1 million years. Its new mass is 3MSun. What was the mass-loss rate each year the super-wind was active? (Enter your answer in MSun/yr.)
- What is the free-fall time of a 10 MSun main-sequence star? O 100 hours O 10 hours O 1 hour O 0.1 hoursCalculate the size of the Schwarzschild radius for the Sun. Choose the option below that most closely matches your answer. Select one: О а. 20 km O b. 1 km О с. 3m O d. 3 km О е. 10 kmPulsars result from a. expanding red giant stars b. white dwarf supernovas c. spinning neutron stars
- Which type of star would be the largest? a. M b. O c. B d. K e. AGiven that a pair of stars are found to be orbiting each other with a period of 11.86 [yrs] and a separation of 5.2 [AU], what is the binary star system's total mass (i.e.- M1+M2) expressed in units of our Sun's mass? a) 61.7 b) 39.5 c) .0162 d) 1 e) 1.0 x 10^30The star Firefly is located 3.0 pc away. If it had an absolute magnitude of 13.0, which value below is reasonable for its apparent magnitude? O A. 10.4 ОВ. 13.3 ОС. -26.7 O D. 15.0
- 5. The approximate relationship between the luminosity and the period of Cepheid variables is Lstar[in units Lsun] = 335 P [in units days]. Delta Cephei has a cycle period of 5.4 days and a parallax of 0.0033 arcseconds. A second Cepheid appears 1/1000 times as bright and has a period of 54days. How far away (in parsecs) is the second more distant Cepheid?Which of the following WOULD NOT characterizes the type(s) of star we would find at g, m, n, o, and p on the Hertzsprung-Russel Diagram (Figure 4) a. are all smaller than q,i,h. b. fuse hydrogen into helium. c. are called, “the main sequence”. d. fuse He into heavier elements. e. get smaller towards the right sideWhen a mass is transferred through the inner Lagrangian point in a binary system toward a white dwarf, the material forms a rapidly growing whirlpool of material known as a(n) a. accretion disk. b. Lagrangian point. c. Algol paradox. d. planetary nebula. e. supernova remnant.