In: Physics
The Gaia satellite will measure parallaxes with an accuracy of 2
× 10−5 arcsec for stars with V < 15.
(a) What is the distance d of an M5 I supergiant with
log(L/Lʘ) = 5.50 and BC = −3.70 that has V = 12, if the
effect of interstellar extinction is ignored?
(b) What is the relative distance accuracy σ(d)/d of such a
star?
(c) Assuming that Teff is known, what is the relative
accuracy in radius σ(R)/R?