WGN America has renewed its period drama “Manhattan” for a second season.

The decision comes a few days before the show’s first-season finale on Sunday. The renewal is not a surprise, as “Manhattan” — the second of the original drama series WGN America has fielded this year — has been generally well-received by critics and generated a small but devoted following. WGN America also renewed its first offering, “Salem,” for a sophomore run.

Set against the backdrop of the development of nuclear weapons in Los Alamos, N.M., in the 1940s, “Manhattan” is averaging about 1.2 million viewers in Nielsen’s Live Plus 7 measure. At this early stage, WGN America can’t expect much in the way of ratings for its originals, so buzz and critical praise is vital. “Manhattan” star John Benjamin Hickey (pictured) in particular has been lauded for his work on the show.

“Manhattan” was created by Sam Shaw and is exec produced by Shaw and helmer Thomas Schlamme for Lionsgate TV, Skydance Television and Tribune Studios. Skydance’s Marcy Ross, David Ellison and Dana Goldberg also exec produce.

“ ‘Manhattan’ represents the kind of high-quality original series we aim to deliver at WGN America, and we couldn’t be more thrilled with the show’s widespread critical acclaim and its loyal audience,” said WGN America/Tribune Studios prexy-g.m. Matt Cherniss. “Sam, Tommy and the talented cast and creative team have so brilliantly brought to life the world of the Manhattan Project and we can’t wait to see what secrets and surprises await us in season two.”

Separately, Tribune Media on Tuesday announced plans for a stock buyback program of up to $400 million. Tribune shares at present trade on the OTC market although the company is in the process of setting up an IPO on a major exchange.