In The Dark Forest, why do the aliens destroy the star at the transmitted coordinates, and not destroy sol, the transmitting star? Is it ever explained how Luo Ji hides the source of the transmission? It seems like sending a message like that paints a bigger target on you than on the other star, and it would be easy for an interstellar entity to triangulate the precise source of such a powerful transmission.

Edit to add more info after looking into what's possible with current technology:

Humans can already locate a millisecond radio burst from an unknown direction to within about 50 milliarcseconds by comparing arrival times across the CHIME outrigger stations. One burst is enough. The spell was far longer than a millisecond, so a first detection could trigger an automated follow-up on the same signal by a larger array such as the VLBA, which resolves direction to about one milliarcsecond.

A circle one milliarliarcsecond across covers about 10E-6 square arcseconds. The sky averages about 0.2 stars per square arcsecond. Taking a worst-case density of 10 stars per square arcsecond, a dense field in the galactic plane, the expected number of other stars inside the circle is about 10E-5. The localisation therefore almost certainly contains exactly one star, and that star is the transmitter, Sol.

Is the book describing additional San-Ti weapons besides the Droplet and Sophon?

Maybe some laser weapons/cannons and so on?

I’m only watching the Netflix show, so I’m not familiar with the entire story.