Question 32Consider three Main Sequence stars, an O tar, an F star and a K star, each with anapparent magnitude of 2. Which star is the most luminous?They're all the same luminosity.The O starThe F starThe K starQuestion 33Consider three Main Sequence stars, an O star, an F star and a K star, each with anapparent magnitude of 2. Which star appears the brightest in the night sky?The O starThe F starO The K starO They all appear the same.Please answerboth

Question 32: Among O star, F star, and K star each with a magnitude of 2 . which one is most…

Answered: Question 32 Consider three Main…

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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
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