Washington: A white-dwarf star has erupted in the constellation Delphinus and has produced a nova that is the brightest since 2007.
Currently shining at magnitude 4.9, the nova can be viewed from dark locations far from city lights, and might remain so for weeks to come.
Tony Flanders, associate editor of Sky and Telescope and host of Sky and Telescope`s PBS TV show SkyWeek, said that the nova is easy to locate north of the lovely star pattern of Delphinus. And the constellation Sagitta, the Arrow, points right toward it.
Arne Henden , Director of the American Association of Variable Star Observers (AAVSO) said that nova is easily visible in the eastern sky in the early evening, so it can be followed for many hours.
He asserted that this means that amateur skygazers and professional scientists alike can continue monitoring it for months to come.
He explained that the nova can be seen with binoculars even from light-polluted metropolitan areas. Hundreds of observers, many for the first time, have submitted brightness estimates of the nova to the AAVSO.
Nova Delphini 2013 was discovered by Koichi Itagaki of Yamagata, Japan, in an image taken at 14 hours Universal Time (2 p.m. EDT) on August 14th. It was not present in a photo that he took the previous day.
The star was apparently 17th magnitude before erupting, so it brightened roughly 100,000-fold to its peak of magnitude 4.5 on August 16th. The nova declined slightly after that, but has held remarkably steady at magnitude 4.9 for the past three days.
A classical nova occurs in a special kind of tightly orbiting binary star system: one where a relatively normal star pours a stream of hydrogen onto the surface of a companion white dwarf.
When the layer of fresh hydrogen on the white dwarf`s surface grows thick and dense enough, the bottom of the layer explodes in a runaway hydrogen-fusion reaction-a hydrogen bomb in the shape of a thin shell roughly the size of Earth.
The underlying white dwarf remains intact, and as new hydrogen builds up, the process may repeat in a few years to tens of thousands of years.