Dr Molnar’ s interest was piqued at a conference in 2013, when Karen Kinemuchi, another astronomer,
presented some puzzling findings on a particular star seen by Kepler, a space telescope designed chiefly to hunt for exoplanets.
When Dr Molnar and his team observed the star—named KIC9832227—they discovered that it was a “ contact binary ”,
a pair of stars so close together that the smaller orbits within the atmosphere of the larger.
They also found that the smaller star was orbiting more quickly—and thus closer to its bigger companion—than it had been when Dr Kinemuchi made her measurements.
Further observations confirmed that the smaller star was indeed spiralling towards its companion.
Based on observations of another contact binary, V1309 Scorpii, which became a nova in 2008,
the researchers were able to offer a prediction of the time of impact that, they hope, should be accurate to within about seven months.
(The most likely date is a fifth of the way through 2022—ie, mid-March.)
Successfully predicting a nova will be of interest to more than just amateur skywatchers.
Astronomers have built mathematical models to describe what happens during such events, but testing them against reality is hard.
All previous novas have been detected after the fact.
Anyone wanting to study what happens before the explosion must therefore sift back through old observations, hoping that some information about the pre-nova star will have been recorded by chance.
Armed with Dr Molnar’ s prediction, though, astronomers will be able to watch the build-up as well as the denouement.