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How far away is a RR Lyrae variable star if it has a period of 0.5 days and a brightness of 2.3 x 10^-11 W/m^2?

1 Answer

1 vote

Answer:

The answer is d =10^6.43 Mpc

Step-by-step explanation:

Solution

To calculate the absolute magnitude of the star, we apply or use the relation with the period

Mv = - [ 2.76 (log₁₀ (P) - 1.0)] -4.16

Here P =+ 0.5 days

Mv = - 0.569

To calculate m, we have the following relation given below:

Mₓ = - 2.5 Log₁₀ (Fₓ/Fₓ,0)

Fₓ,0 = 1 w/m² (This is assumed)

Fₓ = 2.3 * 10^-11 W/m^2 (Given)

Thus

Mₓ = - 2.5 Log₁₀ (2.3 * 10^ ⁻11

Mₓ = 26.595

Now, applying the formula we have the following given below:

d = ₁₀ ( Mₓ -Mv + 5)/5

d =₁₀ (26.595 - 0.569 +5)/5

d =10^6.43 Mpc

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