Question

A star's parallax angle is 0.8. How far away is the star in parsecs?

Answer 1

1.25 parsecs = 4.1 light years, nearly.

Explanation:

The formula is distance d = 1/(parallax angle in radian) AU

I assume that the uni of parallax angle is second.

Here, `d = 1/(0.8(pi/(3600 X 180 ))` AU

`=257831 AU=257831/206264.8 parsec= 1.25` parsec.

Had it been 0.77'', we would have got the distance of the nearest star 4.26 ly = 1.29 parsec of Proxima Centauri..