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How do you find the parsecs and light-years away a star is from the parallax angle? For example, Sirius has a 0.379s parallax angle. How would you get the parsecs and light-years away?

Answer 1

Olivia Aldridge

3-sd approximations: 2.64 parsec = 8.65 ly = 544000 AU..

Regarding your long-term recall:

If #alpha# radian is the parsec angle,

the formula for distance = 1/#alpha# AU.

Here, #alpha#=(0.379/3600)(#pi#/180) radian.=1.8374 E-06 radian.

d=1/1.8374 AU = 544000 AU, thus.

Conversions of units:

From AU units, d = 544000/62000 ly = 8.65 ly in lu units.

From AU units, d=544000/206265 parsec = 2.64 parsec in parsec units.

The 3-sda is used to round all results.

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Answer 2

Owen Atkinson

Distance (in parsecs) = 1 / Parallax angle (in arcseconds) Distance (in light-years) = Distance (in parsecs) * 3.262

For Sirius: Distance (in parsecs) = 1 / 0.379 = 2.64 parsecs Distance (in light-years) = 2.64 * 3.262 = 8.61 light-years

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.