VISUAL PHYSICS ONLINE

8.3 FROM THE UNIVERSE TO THE ATOM

COSMOLOGY, BIG BANG, STARS

P83 1904

Four stars, P, Q, R and S, are labelled on the Hertzsprung–Russell diagram.

(A)

Which is the brightest star?

(B)

Which star is the hottest?

(C)

Which star is in its latest stage of evolution?

(D)

Which star in in its earliest stage of evolution?

(E)

Which star is red in colour?

(F)

Which star is blue in colour?

(G)

State the type of each star.

(H)

Where would the Sun be located on the HR diagram?

Hertzsprung – Russell Diagram Link

View the solution below only after you have completed answering the question. The solution is not in a form that you would answer in an examination. The answers are often in more detail to help improve your appreciation and understanding of the physics.

Solution

(A)

The brightest star is R since it has the highest value of luminosity.

The absolute magnitude of a celestial object is a measure of its luminosity (visual brightness) on a logarithmic astronomical magnitude scale.

(B)

The hottest star is S.

(C)

Latest stage of evolution is star S.

(D)

Earliest stage of evolution is star P.

(E)

Star R is most likely to appear red.

(F)

Star S may be blue in colour or whitest if a white dwarf.

(G)

P main sequence

Q red giant

R red super giant

S most likely a white dwarf

(H)

see diagram