Kepler and Swift spacecraft of NASA provided supporting evidence and the first direct measurement of supernovae (stellar explosions) which can enable scientists to understand what causes supernovae. This was revealed by studies published in journal Nature on 20 May 2015.
The studies proved that Type Ia supernovae, which produce unprecedented brightness, can either be caused by merging with another white dwarf or by pulling too much matter from a nearby companion star. A white dwarf is the Earth-sized remnant of a star like the sun.
The Kepler spacecraft, known for its planet-hunting prowess, has provided the data for three new and distant supernovae, viz., KSN 2011b, KSN 2011c and KSN 2012a. The dataset includes measurements taken before the violent stellar explosions even happened and this is the first direct measurement of supernova.
These supernovae were identified as Type Ia supernovae with the aid of powerful telescopes at the Gemini and the WM Keck Observatories atop Mauna Kea in Hawaii.
On the analysis of dataset, scientists led by Robert Olling, research associate at the University of Maryland, found that shock wave generated in all directions by these explosions were not disrupted. This proved that there was no evidence of a companion star nearby and concluded the cause to be the collision and merger of two closely orbiting stars, most likely two white dwarfs.
Study of Swift dataset
Swift spacecraft captured the supernova designated iPTF14atg first on 3 May 2014 in the galaxy IC 831, located about 300 million light-years away in the constellation Coma Berenices.
The Swift study led by California Institute of Technology (Caltech) graduate student Yi Cao, proved that Type Ia supernovae can also arise from single white dwarfs by pulling too much matter from a nearby companion star.
According to the analysis of Cao, when the supernova debris slammed into and swept around its companion star, it created a region of Ultra Violet (UV) emission and the peak temperature exceeded 19000 degrees Fahrenheit (11000 degrees Celsius) or about twice the surface temperature of the sun.
Type Ia supernovae are destructive explosions of carbon-oxygen white dwarfs and are used empirically to measure cosmological distances. The first direct measurement of such supernovae can help the scientists understand the mysteries of dark energy – a mysterious force that appears to be accelerating cosmic expansion.
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When: 20 May 2015