A jet has an angular length of 10 seconds of arc and flows from a star at a distance of 2,000 pc. How far does this jet extend away from the star
A)20,000 pc
B)20,000 AU
C)20, 000 ly
D)20,000 miles
E)20,000 km

Question

Quizplus · Accepted Answer

To find the actual length of the jet in space, we use the small angle formula, which is $d = \frac{\theta}{206265} \times D$, where $d$ is the actual size of the object, $\theta$ is the angular size in arcseconds, and $D$ is the distance to the object in the same units as $d$. Here, $\theta = 10$ arcseconds and $D = 2000$ parsecs (pc). First, convert the distance from parsecs to astronomical units (AU), knowing that 1 pc ≈ 206,265 AU. So, $D = 2000 \times 206265$ AU.Then, $d = \frac{10}{206265} \times 2000 \times 206265$ AU simplifies to $d = 10 \times 2000$ AU = 20,000 AU.

A Jet Has an Angular Length of 10 Seconds of Arc