While Sirius, the Dog Star, is type AO, a start just a step hotter than M0 is a related what?
A.M1
B.K9
C.F5
D.AOK
E.B9
B. K9
K9 is followed by M0 in the temperature/spectral classification of stars. K's are hotter than M's, and K9 is the coolest of the K's
To determine the answer, we need to understand the temperature and spectral classification of stars. Stars are classified based on their temperature and spectral characteristics. The temperature/spectral classification system uses alphabetical letters (O, B, A, F, G, K, M) to categorize stars on a spectrum from hottest to coolest.
In this system, O-type stars are the hottest and M-type stars are the coolest. The temperature decreases from O to M. Now, we need to find a star that is just a step hotter than M0.
Looking at the options given:
A. M1 - This is a step cooler than M0, not hotter.
B. K9 - This is the correct answer. K9 is followed by M0 in the temperature/spectral classification of stars. K's are hotter than M's, and K9 is the coolest of the K's.
C. F5 - This is even hotter than K and is not just a step hotter than M0.
D. AOK - This is not a valid spectral classification.
E. B9 - B9 is cooler than K, so it's not just a step hotter than M0.
Therefore, the correct answer is B. K9.