When Swarthmore College astronomer David Cohen studied the images he had requested from a NASA satellite telescope, he first wondered if someone had pointed it in the wrong direction.
In one corner of the well-known Southern Cross constellation, there were two stars where there should have been one.
It was no mistake. This month Cohen, along with colleagues at Swarthmore and West Chester University, reported the discovery of a "new" star.
It likely has been around for 10 million years or so but no one ever saw it - in part because the one next to it, Beta Crucis, is so much brighter.
In addition, the two stars are fairly close to each other, at least in relation to their distance from Earth - 352 light-years. Cohen said that trying to see the dimmer star with the naked eye would be like trying to see a firefly next to an automobile headlight at a distance of 60 miles.
The reason Cohen could see it is that NASA's high-resolution telescope, called Chandra, detects X-rays. The new star, though far less luminous than Beta Crucis, emits X-rays that are almost as bright.
It is possible that the new star is just passing through, but Cohen said the evidence so far indicates it is "very likely" to be a companion of Beta Crucis - and thus, a new member of the Southern Cross.
The constellation, which is visible in the Southern Hemisphere, is featured on the flags of Australia and several other countries below the equator.
But there's no need to change all those flags to reflect the new discovery.
"If people had X-ray spectacles," Cohen quipped, "then maybe."
- Tom Avril