In April, a team of scientists based at the University of Cambridge claimed that a planet orbiting a distant star bore a possible signature of life. The announcement kicked up a fierce debate among astronomers, with many skeptics arguing that the evidence was too ambiguous.

Now a NASA-led team has made a new set of observations of the planet known as K2-18b, which lies 124 light-years from Earth. They have provided a clearer picture of the planet — confirming the presence of water, perhaps even as a liquid ocean.

But the new observations have failed to confirm evidence for life. In the original study, the Cambridge team claimed that K2-18b appeared to have a gas in its atmosphere that on Earth is produced only by living things. The NASA study did not find strong evidence for that gas.

What’s more, the NASA team argues that even if the gas was on K2-18b, it might have formed through mere chemistry. What once seemed like a promising clue of life — a biosignature — might be a mirage.

“A key takeaway is that biosignatures are going to be hard, no matter what kind of planet we are talking about,” said Jacob Bean, an astronomer at the University of Chicago, who was not involved in the study.

The NASA team, working with the leader of the Cambridge group, posted its new results online last week. The scientists have submitted the study to a scientific journal for publication.