Using the Technique of Main- Sequence Fitting to Determine the Distance

question 40

Multiple Choice

Using the technique of main- sequence fitting to determine the distance to a star cluster requires that .

• A)we use ultraviolet and X- ray telescopes
• B)we have telescopes powerful enough to allow us to identify the spectral types of main- sequence stars of many masses in the cluster
• C)the cluster be near enough for us to measure the parallax of its stars
• D)we have a well- calibrated period- luminosity relation for Cepheid variable stars

---

Definitions:

Interest Rate

A percentage that measures the amount of interest due per period, as a proportion of the amount lent, deposited, or borrowed.

Equal Payments

A series of payments of the same amount made at regular intervals for a specified period of time.

Loan Date

The specific date on which a loan agreement goes into effect or when the loan funds are disbursed.

Interest Rate

The percentage of a loan amount charged by the lender to the borrower for the use of money, expressed as an annual percentage.