The collision was easily seen with the naked eyes, but the debris after the collision were so faint that the astronomers needed submillimeter telescope to unravel the mystery several centuries later.
The father of lunar mapmarking, Hevelius and Cassini, who discovered four of saturns moons documented the new star in 1670.
Hevelius described it as “a new star below the head of the swan.” It is now known as “Nova Vulpeculae 1670”
Nova means a type of stellar outburst. Nova Vul 1670 was the oldest recorded nova.
“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 the study’s lead author, Tomasz Kaminski.
In the last century it was learned that most novae occur when a star pulls away material from a companion star leading the material to eventually explode.
But Nova Vul 1670 didn’t fit in this category and remained mystery.
With the increasing telescopic power also it was believed that the nova didnt left any traces. It was in 1980 when the astronomers discovered a cloud where the remains could be found.
They probed the clouds using light waves of particular wavelength. The length of the light waves determines their energy and color and this have revealed a very unusual chemical composition.
“We have now probed the area with submillimeter and radio wavelengths. We have found that the surroundings of the remnant are bathed in a cool gas rich in molecules,” said Tomasz Kaminski from the European Southern Observatory (ESO) and the Max Planck Institute for Radio Astronomy in Bonn, Germany.
The astronomers has analyzed the chemical composition and measured ratio of different isotopes in the gas. They concluded that there is too much of the cool material to conclude it to be nova.
So what is it? So this could be a collision between two stars. This collision produces red transient, an event where star explode due to a merger with another star. They threw materials from the stellar interior to the space leaving behind faint remnant in a cool environment, rich in molecules and dust.