Step 1: Make figure from the given information

Diameter of the earth OB = 3* 10^{11} m

Radius of the earth = \frac{OB}{2} = 1.5 * 10^{11} m

Parallax angle \theta = 1 ''

\theta = 1 * \frac{1}{60* 60} * \frac{\pi}{180} = 4.847* 10^{-6} radians

Distance between the earth and star = BC = d

Step 2: Using the parallax method to find the large distance (d)

Formula: Parallax angle \theta = \frac{OB}{BC}

BC = \frac{OB}{\theta}

BC = \frac{1.5 * 10^{11}}{4.847* 10^{-6}}

BC = 3.09 * 10^{16}

Hence, 1 \text{ persec } = 3.09 * 10^{16} m

I found an answer from byjus.com

**Measurement** Of **Length** - Triangulation And **Parallax Method**

Know about **the** triangulation **method** of **measuring distance**, and **parallax** ... and
**the** obtained values are expressed in light-years or astronomical **units**. ...
**Distance measurement** by **parallax** is a special **application** of **the** principle of
triangulation. ... Here **the maximum** value of' 'd' is **the** radius of Earth and **the**
**distance** of **the** ...

For more information, see **Measurement** Of **Length** - Triangulation And **Parallax Method**

I found an answer from roman.gsfc.nasa.gov

2015 WFIRST-AFTA SDT Report

Mar 10, 2015 **...** port concludes: “If **used** for the WFIRST mission, the. 2.4-meter telescope ...
characterize **an Earth**-like planet **around** a nearby **star**. ... merits of inclined
geosynchronous and **Sun**-**Earth** L2 **orbits**. ... **points**, **most** notably (a) that the SN
**distance** scale is ... exposure time of the **baseline** survey is 174 sec per.

For more information, see 2015 WFIRST-AFTA SDT Report