NASA's Kepler Space Telescope has captured a rare death of a star wrapped inside a dense layer of gas and dust, which ended in an intense explosion that's unlike any other supernovae.
Before reaching its ultimate end, the cocooned star known as KSN 2015K had several near-death experiences. However, when it finally blew up, its kinetic energy slammed into the shell and was immediately converted into light.
An Extreme Example Of A Fast-Evolving Luminous Transient
This astronomical event is called by scientists as "Fast-Evolving Luminous Transient." The recent one occurred at a distance of 1.3 billion light-years away from the Earth, reached its peak by 2.2 days, and half of its brightness faded after 6.8 days.
A report states that KSN 2015K has completely disappeared by 25 days, a rate that's 10 times faster than a typical supernova.
For the past decade, FELTs have left astronomers puzzled about their extremely short duration. Now, an international team uncovered the nature of these phenomena, ruling previous theories about their origin.
In the past, they have been explained as an afterglow of a gamma-ray burst, a supernova that got turbo-boosted by a neutron star with a strong magnetic field, also known as "magnetar;" or the failed explosion of a type Ia supernova.
These theories are based on the typical model of a supernova, but the team realized that such model is not applicable for FELTs.
"This is a new way for massive stars to die and distribute material back into space," says Armin Rest of Maryland's Space Telescope Science Institute in a report.
Moreover, observations by the Kepler Space Telescope reveal that the mysterious cocoon does not come from the star's surroundings. Less than a year before its death, the stellar object itself ejects the shell of gas and dust through "mini-eruptions."
The same findings have been obtained through the Australian National University's SkyMapper telescope after the data it recorded was processed by the institution's National Computational Infrastructure.
More details about cocooned stars are found in the team's study, which was published in the March 26 issue of the journal Nature Astronomy.
Kepler Space Telescope And K2 Mission
KSN 2015K was discovered under the Kepler's four-year K2 mission to closely monitor over 150,000 stars to search for exoplanets. It became fully operational May 2014 and is expected to continue until 2018.
According to Rest, they will look for more FELTs during the ongoing K2 mission or in the next mission using NASA's new TESS space telescope.
