Researchers watched the thermonuclear fireball that appeared after a nova eruption last year with "unprecedented clarity."
The observations provide the first images of a nova during its infantile fireball stage, Georgia State University reported. The new star, dubbed Nova Delphinus 2013, was discovered on Aug. 14, 2013.
A nova occurs when hydrogen builds up on the surface of a white dwarf star, leading to thermonuclear fusion, or a "stellar H-bomb." The study revealed how the structure of ejected material changes as the gas expands and cools down; the findings suggest these structural changes are more complicated than previously believed.
The light from such a high-intensity explosion would be noticeably brighter than the star's usual glow. To the naked eye this would appear as an extremely bright star in area not known to contain one that would slowly fade over the course of several weeks.
Within 15 hours of the star's discovery (and 24 hours of its explosion) the researchers pointed the telescopes of the CHARA Array towards the event. They measured the fireball's size and shape for 27 nights over the course of two months, and the earliest measurement is the earliest size obtained for a supernova event.
The team determined Nova Del 2013 is at a distance of 14,800 light years from the sun, meaning it took place about 15,000 years ago based on how long the light took to reach Earth. The physical size of the fireball was believed to be about as large as Earth's orbit. The explosion was not spherical in shape, but rather had an elliptical appearance. The findings provide insight into how the material is ejected from the surface of the white dwarf during the explosion. The observations have shown the outer layers become more transparent as the fireball expands.
The study was possible because technology created over only the past decade allowed the researchers to image the earliest stages of the explosion in high-resolution.
The findings were published in a recent edition of the journal Nature.
