Consider a relatively nearby, single star, that is, a star that is not a member of a binary system and has no known orbiting planets. listed below are a few properties of this star. classify each property as either something that we can observe or measure directly (with the aid of a telescope and instruments such as cameras or spectrographs) or something that we must infer indirectly (and hence is correct only if all of our assumptions are correct).
infer indirectly
a. color
b. parallax angle
c. spectral type
d. apparent brightness
e. luminosity
f. surface temperature
g. mass
h. radius