Zeta 2 Reticuli is not necessarily the star system in which the Nostromo found the derelict spacecraft.
Despite the published evidence otherwise, it does not seem certain that the planetoid, on which the Nostromo set down, is in the Zeta II Reticuli system.
In the 1979 sf-horror film, Alien, the Nostromo is diverted to investigate a transmission on its way back to Earth. When the crew scan the area, the navigator (Lambert) states the following (cited by source):
ON-SCREEN:
LAMBERT. I found it. Just short of Zeta II Reticuli. We haven't even reached the outer rim yet. [Alien. Dir. Ridley Scott. Perf. Sigourney Weaver, Ian Holm, Tom Skerritt. 20th Century Fox, 1979.]
IN THE SCREENPLAY:
LAMBERT Found it. Just short of Zeta II Reticuli. We haven't even reached the outer rim yet. [Hill, Walter and David Giler. Alien. Revised Final Script. Oct. 4, 1978.]
IN THE NOVELIZATION:
Several minutes of intense searching and computer-cooperation produced a tight grin of satisfaction on her face. "Found it . . . and us. We're just short of Zeta II Reticuli. We haven't even reached the outer populated ring yet. Too deep to grab onto a navigation beacon, let alone a Sol traffic relay." [Foster, Alan Dean, Dan O'Bannon, Ronald Shusett, and H. Roberts. Alien. New York: Warner , 1979. Print. p. 23]
Based on this evidence, it seems that the Nostromo exited hyperspace "just short of Zeta II Reticuli", but then proceeded to the source of the transmission elsewhere, apparently in a nearby star system, probably minor.
