In: Physics
You have discovered a new galaxy and you think you have identified an Type II Cepheid star with a period of 30 days. You measure its brightness and with the Period-Luminosity function you calculate the distance to the galaxy d. However, you later find out that in fact the star you had identified is a Type I Cepheid. Is the galaxy further than, or, close to, us than we previously expected? By what factor should you multiply d to get the correct distance to the new galaxy? [Hint: check the diagram in the slides for the Distance Ladder lecture]