Download E3 STELLAR DISTANCES E4 COSMOLOGY

Student Notes
th
Source: Physics for the IB Diploma, 5 Ed, Tsokos
E3 STELLAR DISTANCES
E4 COSMOLOGY
Source: Physics for the IB Diploma, 5th Ed, Tsokos
EXAMPLE 1
The distance to the star Epsilon Eridani is
10.8 ly. What is it’s parallax angle?
[0.30”]
1
Source: http://frigg.physastro.mnsu.edu
Source: Stars and Planets Field Guide, Menze/Pasachoffl
EXAMPLE 2
Determine the apparent magnitude of a star
whose apparent brightness is 6.43 x 10-9 W
m-2.
[1.48]
EXAMPLE 3
Determine the apparent brightness of a star
having apparent magnitude m = 4.35.
[4.58 x 10-10 W m-2]
2
Source: Physics for the IB Diploma, 5th Ed, Tsokos
Source: Physics for the IB Diploma, 5th Ed, Tsokos
.
EXAMPLE 4
Calculate the absolute magnitude of a star
whose distance is 25.0 ly and whose
apparent magnitude is 3.45
[4.03]
EXAMPLE 5
Using the data above, determine the distance
to the star Sirius.
[2.7 pc]
3
EXAMPLE 6
A main sequence star emits most of its energy at λ = 2.4 x 10-7 m. Its apparent brightness is
measure at 4.3 x 10-9 W m-2. How far away is the star?
[28 pc]
EXAMPLE 7
Determine the distance between Earth and the star whose light curve is shown.
[520 pc]
4