In 1670, European astronomers witnessed a strange explosion in the sky, which scientists recorded as the first nova. New research suggests that the incident was in fact a stellar collision between two stars.
The stellar explosion that took place about 345 years ago was brighter than a nova but not as bright as a supernova. However, the explosion was so strong that it was also visible to the naked eye during the initial outburst.
Astronomers of the 17th century described that they witnessed a new star that appeared in the head of Cygnus, the swan constellation. The nova was dubbed Nova Vul 1670 and later renamed as CK Vulpeculae. However, latest observations from APEX and other telescopes suggest that the explosion was not a nova but a violent stellar collision.
"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," says Tomasz Kaminski, an European Southern Observatory (ESO) fellow and the lead author of the study.
Kaminski says that while the celestial event was well-documented, astronomers of that time did not have the equipment to understand it properly.
The explosion is said to have left faint traces. In the 1980s, a group of astronomers detected a dim nebula that surrounded the remnants of the star. The area is rich in molecules that have very distinct chemical composition.
Research of the region with various telescope revealed that the mass of the material was actually too great to be the product of a nova explosion. Isotope ratios measurements also revealed that it was not a nova explosion.
Scientists suggest that the celestial event was actually a collision of two stars that produced a red transient. Scientists also highlights that such an occurrence is quite rare and leaves behind faint remnant that is surrounded in cool environment.
Kaminski says that the celestial event is also referred to as the red nova, which is a relatively new phenomenon known to science. Astronomers and researchers are still working to understand the event better.
Kaminski suggests that the CK Vulpeculae is currently thought to be a red nova. However, in the next few years it is possible that scientists find a different explanation for the stellar explosion of 1670.
