PROBLEM SET #3

ASTR 1040

The spreadsheet carries a list of stars together with their apparent magnitudes, distances, and temperatures. For each one calculate the absolute magnitude and enter it in the blank column labeled M. Use the formula:

where d is the distance in parsecs to have Excel calculate M for you.

2. Use interpolation from the following table to estimate the spectral type of each star. Enter type in column Spectral Type. (If you don't know what interpolation means, look it up!)

Spectral Type                 Temperature (K)

O5                                   40,000
B0                                    28,000
B5                                    15,500
A0                                     9,900
A5                                     8,500
F0                                      7,400
F5                                      6,580
G0                                      6,030
G5                                      5,520
K0                                      4,900
K5                                      4,130
M0                                      3,480
M5                                      2,800
M8                                      2,400

3. Use Excel to make an H-R Diagram.  Or feel free to use some other computer software to make your plot.

4. Classify each star as main sequence (M), giant (G), or white dwarf (W) and enter that number in the column.

5. Use the fact that the Sun has an absolute magnitude of 4.5 and scaling from the Stefan-Boltzmann Law to calculate the radius of each star in Solar Radii.