(Added more info)

Need help with these.

Galaxy is NGC 6822

Ref star apparent magnitude is 15.25

Title Variable Star Mag + (15.25 - Reference Star Mag) 13.20 13.30 13.40 13.50 13.60 13.70 13.80 55,080 55,100 55, 120 55,140 55,160 55,180 55,200 55,220 55,240 55,260 55,280 Variable Star Mag + (15.25 - Reference Star Mag) + 20 18 16 14 12 Power Spectrum 10 8 6 4 N 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Period (sec) Question: The time between peaks (or troughs) is the period. Record the period (P). (1 point) days Question: Is this period consistent with the star being a Cepheid star? (1 point) Yes O NO Question: If so, calculate the star's average absolute magnitude (M) (think average luminosity) to 0.01 magnitudes? (1 point) Show your work. (1 point) Question: Half the distance between the peak and the trough is the average apparent magnitude (m) (think average brightness) of the star. Estimate this to 0.05 magnitudes. (1 point) Question: Calculate the distance (D) to the Cepheid star, and hence to the nearby galaxy, using its absolute and apparent magnitudes. (1 point) kpc Show your work. (1 point) Question: Wiki and record the true distance (D) to NGC 6822. (1 point) kpc Question: Calculate your percent error. (1 point) Question: Discuss significant sources of error. (2 points) Title Variable Star Mag + (15.25 - Reference Star Mag) 13.20 13.30 13.40 13.50 13.60 13.70 13.80 55,080 55,100 55, 120 55,140 55,160 55,180 55,200 55,220 55,240 55,260 55,280 Variable Star Mag + (15.25 - Reference Star Mag) + 20 18 16 14 12 Power Spectrum 10 8 6 4 N 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Period (sec) Question: The time between peaks (or troughs) is the period. Record the period (P). (1 point) days Question: Is this period consistent with the star being a Cepheid star? (1 point) Yes O NO Question: If so, calculate the star's average absolute magnitude (M) (think average luminosity) to 0.01 magnitudes? (1 point) Show your work. (1 point) Question: Half the distance between the peak and the trough is the average apparent magnitude (m) (think average brightness) of the star. Estimate this to 0.05 magnitudes. (1 point) Question: Calculate the distance (D) to the Cepheid star, and hence to the nearby galaxy, using its absolute and apparent magnitudes. (1 point) kpc Show your work. (1 point) Question: Wiki and record the true distance (D) to NGC 6822. (1 point) kpc Question: Calculate your percent error. (1 point) Question: Discuss significant sources of error. (2 points)