14 Suppose you see two main-sequence stars of the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude? (Neglect any effects that might be caused by interstellar dust and gas.) A B C D Star 1 is 10 times more distant than Star 2. The luminosity of Star 1 is a factor of 100 less than the luminosity of Star 2. Star 1 is 100 times nearer than Star 2. Star 1 is 100 times more distant than Star 2. E Without first knowing the distances to these stars, you cannot draw any conclusions about how their true luminosities compare to each other.

14 Suppose you see two main-sequence stars of the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude? (Neglect any effects that might be caused by interstellar dust and gas.) A B C D Star 1 is 10 times more distant than Star 2. The luminosity of Star 1 is a factor of 100 less than the luminosity of Star 2. Star 1 is 100 times nearer than Star 2. Star 1 is 100 times more distant than Star 2. E Without first knowing the distances to these stars, you cannot draw any conclusions about how their true luminosities compare to each other.

Stars and Galaxies (MindTap Course List)

10th Edition

ISBN:9781337399944

Author:Michael A. Seeds

Publisher:Michael A. Seeds

Chapter12: Stellar Evolution

Section: Chapter Questions

Problem 6P

See similar textbooks

Similar questions

Which of the following can you determine about a star without knowing its distance, and which can you not determine: radial velocity, temperature, apparent brightness, or luminosity? Explain.
"51 Pegasi" is the name of the first normal star (besides the Sun) around which a planet was discovered. It is in the constellation Pegasus the horse. Its parallax is measured to be 0.064 arcsec. a. What is its distance from us? b. The apparent brightness is 1.79 × 10-10 J/(s·m2 ). What is the luminosity? How does that compare with that of the Sun? Look up the temperature: how do
12. A star with spectral type MO has a surface temperature of 3750 K and a radius of 0.63 Rsun: How many times more luminous is this star than the Sun? (if it is less luminous enter a number less than one) Answer: Submit All Answers Last Answer: 0.0923 Incorrect, tries 1/5. Hint: Use the Luminosity equation, which says that L is proportional to R^2 T^4. If you keep these as ratios compared to the sun, your L will also come out as a ratio compared to the Sun. This star has a mass of 0.4 Msun- Using the simple approximation that we made in class, what is the main sequence lifetime of this star? You may assume that the lifetime of the sun is 1010 yr. Answer: Submit All Answers Compare this to the lifetime of a MO star listed in Table 22.1 (computed using a more sophisticated approach). Is the value you calculated in the previous problem longer or shorter than what is reported in the table? (L for longer, S for shorter) (You only get one try at this problem.) Answer: Submit All Answers
. The spectrum of Star A peaks at 700 nm. The spectrum of Star B peaks at 470 nm. We know nothing about what stage of stellar evolution either of these stars are in. Which of the following are true? A. Star A has a higher luminosity than Star B. B. Star B has a higher luminosity than Star A. C. Star A is cooler than Star B. D. Not enough information to comment on their luminosities. E. B and C F. C and D
QUESTION 10 Which of the following Cepheid variable stars would appear to be the brightest from Earth? A Cepheid variable star that is 10,000 times as luminous as the sun. A Cepheid variable star with a period of 10 days. A Cepheid variable star with a period of 3 days. There is not enough information given.
2. If Vega is apparent magnitude zero, and Deneb first magnitude, then Vega must be 2.5× hotter than Deneb. Vega is 2.5× brighter than Deneb. Vega is about 100× brighter than Deneb. Deneb is one magnitude brighter than Vega. Deneb must be a main sequence star, and Vega a giant.
12: A star with spectral type A0 has a surface temperature of 9600 K and a radius of 2.2 RSun. How many times more luminous is this star than the Sun? (if it is less luminous enter a number less than one) Answer: 36.854 13:This star has a mass of 3.3 MSun. what is the main sequence lifetime of this star? You may assume that the lifetime of the sun is 1010 yr. Please answer question 13 thank you.
Assume that an O main-sequence star (40,000 K) and a G main-sequence star (5,500 K) have the same radius. How many times brighter is the O star? LO LG = Star B is located 2.6 times farther from earth than Star A, but both have the same apparent visual magnitude of 1 mag. Which star is intrinsically brighter?How many times brighter is the star? If a star has an apparent magnitude equal to its absolute magnitude, how far away is it in parsecs? pc
A group of graduate students, bored during a cloudy night at a the observatory, begin to make bets about the time different stars will take to evolve. If they have a cluster of stars which were all born roughly the same time, and want to know which star will become a red giant first, which of the following stars should they bet on? a. a star that would type O on the main sequence star b. a star about 1/2 the mass of our sun c. a star about 8% the mass of our sun d. all stars reach the red giant stage in roughly the same number of years
Which of the following binary star systems cannot exist? A. A 1 solar-mass main sequence star and a 4 solar mass red giant with a size 100 times smaller than the orbital distance. B. A 15 solar-mass main sequence star and a 10 solar mass red giant with a size 100 times smaller than the orbital distance. C. A 1 solar-mass main sequence star and a 4 solar-mass main sequence star. D. A 2 solar-mass main sequence star and a 1 solar mass red giant with a size a few times smaller than the orbital distance.
4. Suppose we observe a binary star system in which one star is much more massive than the other and both are on the main sequence. We measure that the smaller star orbits the larger at a distance of 10¹3 m with a speed of 10 m/s. a. What is the mass of the larger star? b. Which star has a higher luminosity? c. Which has a larger radius? d. Which is hotter?
1. Suppose you observe a tight eclipsing binary with orbital period of 3 days, and radial velocity semi-amplitude for both components of 80 kilometers/second. a. Without doing any calculation, you know that the mass ratio of the binary is 1:1. Explain why? b. What are the masses and orbital radii of the two stars? c. Suppose the binary is perfectly aligned so each eclipse the center of one star goes across the other. How often do you see an eclipse? d. Suppose one eclipse lasts for 3.5 hours. What is the radius of the stars?