Scientists have captured images of the growing thermonuclear fireball from a nova eruption that occurred in 2013 in the Delphinus constellation.
Astronomers from the Georgia State University's Center for High Angular Resolution Astronomy (CHARA) reveal that 17 institutions and 37 researchers took part in the research and observed the nova eruption.
Koichi Itagaki, an amateur Japanese astronomer, discovered the star on Aug. 14, 2013 and it was called Nova Delphinus 2013.
Scientists explain that a nova normally occurs when a thin hydrogen layer builds over a white dwarf's surface, a star that has Earth's equivalent of diameter and has about the same mass as that of our sun. The white dwarf's gravity normally produces enough pressure at the bottom of the hydrogen layer, which results in a thermonuclear explosion.
The light generated from the stellar explosion exceeds the star's regular brightness and it may also be visible to the bare eye at a location that previously did not show stars with high radiance. The expansion of the fireball and the cooling off process eventually fade the fireball.
The study reveals that the astronomers pointed their high-resolution telescopes toward the nova within just 15 hours from its discovery and also within 24 hours of the explosion. The astronomers were able to measure the shape and size of the fireball, spanning 27 nights within a 2-month period.
By measuring the nova's expansion, astronomers were able to establish that Nova Del 2013 is 14,800 light years from the sun, which means that the nova explosion observed on Earth occurred about 15,000 years back. Initial CHARA observations revealed that the size of the fireball was nearly the same size as that of Earth's orbit. After 43 days of explosion it expanded massively.
"When last measured 43 days after the detonation, it had expanded nearly 20-fold, at a velocity of more than 600 kilometers per second, to nearly the size of Neptune's orbit, the outermost planet in our solar system," according to the research.
The astronomers observed that the outer layer became very transparent as the fireball expanded. The study also found the nova explosion was not accurately spherical, but was slightly elliptical in shape. The scientists suggest that the observation is significant as it can provide hints on how materials are spewed from a white dwarf's surface during an explosion.
The research has been published in the journal Nature.
