The 17th century must have been an exciting time to be an astronomer, what with so many things in the universe still undiscovered. However, technology at the time would have made it an uneventful time, as well. That is, until 1670, when European astronomers observed a brand new star in the sky, so bright it could easily be seen with the naked eye. The event, which came to be known as Nova Vulpeculae 1670, is said to have burned brightly for two years, then vanished without a trace. Some 340 years later, astronomers have finally solved the puzzle – Nova Vulpeculae 1670 wasn’t a nova at all.
“For many years this object was thought to be a nova, but the more it was studied the less it looked like an ordinary nova — or indeed any other kind of exploding star,” said Tomasz Kamiński of the ESO and the Max Planck Institute for Radio Astronomy, Bonn, Germany.
Modern scientists weren’t the only ones to conclude that the event was a nova. The earliest astronomers, including including Hevelius and Cassini, documented the new star. Hevelius even went so far as to describe it as nova sub capite Cygni, or “a new star below the head of the Swan.”
As the years wore on and technology improved, scientists still didn’t have much in the way of a better picture of what people really saw in 1670. Having identified a reliable pattern for novas, they knew most could be identified and explained by the runaway explosive behavior of close binary stars – except, this didn’t fit Nova Vulpeculae 1670 at all. Scientists in the 1980s were able to detect a very faint nebula near where the star was supposedly seen, but it did little to explain what actually happened.
Now, astronomers are able to use the ESO’s APEX telescope along with the Submillimeter Array and the Effelsberg radio telescope to probe deeper into space than ever before. What they found that the area surrounding Nova Vul’s remnant is blanketed in cool gas, rich with molecules with what they call a “very unusual” chemical composition. Again, very un-nova like. So what is it?
The scientists determined that the mass of the cooled, curious gaseous area was too large to have been produced by a nova – it must have been something bigger. After ruling out a supernova (which leaves a tell-tale red transient), they concluded that it must have been a still-spectacular collision between stars, more powerful than a standard nova. Though rare, such collisions produce spectacular explosions, bathing the surrounding areas in molecule- and dust-rich gas, just as they observed with Nova Vulpeculae 1670.
If only those early astronomers knew just how spectacular their discovery was.