IC 4996 is thought to form a double cluster with the P Cygni Cluster, which has the bright star 34 Cygni at its eastern edge.
P Cygni gradually faded below 6th magnitude and then experienced a similar meteoric rise in 1655 followed by smaller fluctuations.
P Cygni and its associated clusters are approximately 7,500 light-years away.
2" P Cygni Cluster Open cluster -- 5' P Cygni Variable star 4.
A Milky Way star called P Cygni
, which brightened and shed a tenth of a solar mass in 1600, may have undergone even fiercer outbursts over the past few thousand years, Smith and others note.
At first glance, P Cygni in the heart of the Northern Cross might look like a run-of-the-mill variable star.
Astronomers suspect that P Cygni ejected gaseous shells during its recent eruptions.
O'Connor and his coinvestigators report that the arc "appears to be associated with P Cygni and not simply foreground or background nebulosity.
In analyzing recent and historical observations of a star called P Cygni, however, scientists have found that this Milky Way resident has increased steadily in brightness over the past 300 years -- indicating it has aged significantly in the twinkling of an astronomical eye.
That celestial object, a blue supergiant called P Cygni, lies some 6,000 light-years from Earth in the constellation Cygnus (the Swan) and is about 30 times as massives as the sun.
P Cygni has been visible to the naked eye ever since Dutch cartographer Willem Janszoon Blaeu first spotted it on Aug.
5 [degrees] south-southwest along the neck of Cygnus to 34 or P Cygni
, then another 1.