Astronomers discover a new type of supernova explosion

Caltech astronomers have recently observed the particular death of a massive star that exploded in a surprisingly weak supernova and that faded quickly.

These perceptions suggest that the star has an invisible companion, gravitously sinking endlessly the mass of the star to abandon a star stripped that exploded in a fast supernova. It is assumed that the explosion caused the formation of a dead neutron star in orbit around its compact and thick companion, recommending that researchers have witnessed the introduction of a minimal neutron star binary system.

When a massive star – at least eight times the mass of the sun – lacks fuel to burn in its core, the nucleus collapses inward and bounces back into a powerful explosion called a supernova. After the explosion, all the outer layers of the star were swept away, leaving behind a dense neutron star, the size of a small town but containing more mass than the sun. A teaspoon of a neutron star would weigh as much as a mountain.

Mansi Kasliwal (MS '07, PhD '11), Assistant Professor of Astronomy, said: "We have witnessed the collapse of the nucleus of this massive star, but we have seen a mass mass ejected remarkably low. We call this an ultra-stripped envelope supernova and have long predicted their existence. This is the first time we have convincingly seen the collapse of the nucleus of such a massive star that has no material left. "

The fact that the star exploded implies that it had to be wrapped before in a multitude of materials, otherwise its core would never have become heavy enough to collapse. But where was the missing mass?

The experts deduced that the mass had probably been stolen – the star had to have some kind of compact and dense companion, either a smaller white person, a neutron star or a dark space – close enough to be able to siphon gravity off its mass before it explodes. The abandoned neutron star of the supernova then had to be naturally introduced into orbit with this dense companion. Observing iPTF 14gqr actually observed the introduction of a smaller neutron star binary. Since this new neutron star and its partner are so close to each other, in the long run they will converge to an impact similar to that of 2017, which produced both gravitational waves and electromagnetic waves.

The iPTF 14gqr is not exclusively an exceptional opportunity, it's lucky that it has been seen, as these wonders are both unusual and brief. Of course, it was only through the observations of the initial phases of the supernova that the specialists were able to determine the starting points of the explosion as a massive star.

From said, "You need fast and transient investigations and a well-coordinated network of astronomers around the world to actually capture the initial phase of a supernova. Without data at its inception, we would not have been able to conclude that the explosion had to come from the nucleus being collapsed from a massive star with an envelope about 500 times the ray of the sun. "

The event was first seen at the Palomar Observatory as part of the Palomar Transient Factory (iPTF), a nocturnal study of the sky aimed at looking for transient or short-lived cosmic events, such as than supernovae. Because the iPTF study monitors the sky so closely, the iPTF 14gqr was observed in the very first hours after its explosion. While the Earth was spinning and the Palomar telescope was out of reach, astronomers from around the world collaborated to monitor the 14Gqr iPTF, constantly observing its evolution with several telescopes that form today the network of GROWTH observatories.

The Zwicky Transient Facility, successor of the iPTF at the Palomar Observatory, is examining the sky even more widely and frequently in the hope of capturing more of these rare events, which account for only 1% of all the explosions observed. These surveys, in partnership with coordinated monitoring networks such as GROWTH, will allow astronomers to better understand how compact binary systems evolve from massive binary stars.

The research was primarily funded by the National Science Foundation as part of the PIRE GROWTH project. The Science study entitled "A hot, fast, ultra-stripped supernova, probably forming a compact neutron star binary" contains a complete list of funding sources and co-authors. Besides De and Kasliwal, other Caltech co-authors are Gary Doran of the Jet Propulsion Laboratory; Gina Duggan, graduate student; Shri Kulkarni, Professor of Astronomy and Planetary Science (George Ellery Hale); and Russ Laher and Frank Masci of the Caltech Infrared Processing and Analysis Center.

The research was conducted by graduate student Kishalay De and is featured in an article in the Oct. 12 issue of the journal Science.