It’s not uncommon to find a surviving star on the scene of a titanic supernova explosion that should wipe out everything around it, but recent research into the Hubble Space Telescope has provided a long-awaited clue about a particular type. Death. In some supernova cases, astronomers find no trace of the outermost hydrogen layer of the ancient star. What happened to hydrogen? Suspicions that companion stars are responsible – sucking the outer shell of their partners before they die – are supported by Hubble’s identification of a surviving companion star on the scene of the 2013ge supernova.
The discovery also supports the theory that the majority of massive stars form and evolve as binary systems. This could also be the prelude to another cosmic drama: over time, the surviving massive companion star will also experience a supernova, and if the two remaining star nuclei are not thrown out of the system, they will eventually merge and produce gravitational waves that shake the space itself. fabric.
NASA’s Hubble Space Telescope has discovered a witness at the scene of a star’s explosive death: a companion star previously hidden in the glow of its partner’s supernova. The discovery is the first for a particular type of supernova – one in which the star was stripped of its entire outer mantle of gas before exploding.
The discovery provides crucial insight into the binary nature of massive stars, as well as the potential premise of the ultimate fusion of accompanying stars that would shake the universe like gravitational waves that wave in the very space-time structure.
Astronomers discover the signature of various elements in supernova explosions. These elements are superimposed as a pre-supernova bulb. Hydrogen is found in the outermost layer of a star, and if hydrogen is not detected after the supernova, it means it was removed before the explosion.
The cause of the hydrogen loss was a mystery, and astronomers used Hubble to search for clues and test theories to explain these stripped-down supernovae. The new Hubble observations provide the best evidence yet to support the theory that an invisible companion star siphons its partner star’s gas envelope before exploding.
“It was the moment we’ve been waiting to finally see evidence of a completely stripped-down supernova ancestor binary system,” said astronomer Ori Fox of the Space Telescope Science Institute in Baltimore, Maryland, chief investigator of the program. Hubble Search. “The goal is to take this field of study from theory to work with data and see what these systems really look like. »
The Fox team used Hubble’s Wide Field Camera 3 to study the 2013 supernova region (SN) in ultraviolet light, along with previous Hubble observations in the Barbara A. Mikulski Archive for Space Telescopes. Astronomers saw the light from the supernova fade over time from 2016 to 2020 – but another source of nearby ultraviolet light in the same position retained its brightness. This underlying source of ultraviolet emission is what the team proposes as the surviving binary companion for SN 2013ge.
Two and two?
Earlier, scientists had speculated that strong winds from a massive tribal star could blow its shell of hydrogen gas away, but observational evidence did not support this. To explain the interruption, astronomers have developed theories and models in which a binary companion sucks hydrogen off.
“In recent years, many different sources of evidence have told us that stripped-down supernovae are probably formed in binaries, but we had not actually seen the companion yet. Thanks to Hubble, we can see this directly,” said Maria Drout of the University of Toronto , a member of the Hubble Research Team.
In previous SN 2013ge observations, Hubble saw two peaks in ultraviolet light instead of the one typically seen in most supernovae. Fox said one explanation for this double enlightenment was that the second climax shows when the shock wave from the supernova hit a companion star, a possibility that now seems much more likely. Hubble’s recent observations indicate that although the companion star was significantly shaken up, including the hydrogen gas it had sucked from its partner, it was not destroyed. Fox compares the effect to a shivering bowl of jelly, which will eventually return to its original shape.
Although further confirmation and similar supporting findings need to be found, Fox said the implications of the discovery are still significant, supporting theories that the majority of massive stars form and evolve as stars.binary systems.
One to look at
Unlike supernovae, which have an undulating shell of gas to be illuminated, ancestors of fully stripped casing supernovae have proven difficult to identify in images before explosion. Now that astronomers have had a chance to identify the surviving companion star, they can use it to trace back and determine the characteristics of the exploding star, as well as the unprecedented opportunity to see the aftermath unfold with the survivor.
As a massive star himself, SN 2013’s companion is also destined to experience a supernova. Its former partner is now likely to be a compact object, like a neutron star or black hole, and the companion is likely to go that route as well.
The proximity of the original companion stars will determine if they stay together. If the distance is too great, the companion star will be thrown out of the system to wander through our galaxy on its own, a fate that may explain many seemingly solitary supernovae.
But if the stars were close enough together before the supernova, they would continue to orbit each other like black holes or neutron stars. In this case, they would eventually spiral toward each other and merge, creating gravitational waves.
This is an intriguing perspective for astronomers, as gravitational waves are a branch of astrophysics that has only just begun to be explored. They are waves or ripples in the very fabric of space-time, predicted by Albert Einstein in the early 20th century. Gravitational waves were first observed directly by the Laser Interferometer’s Gravitational Wave Observatory.
“With the surviving companion to SN 2013ge, we could potentially see the prequel to a gravitational wave event, even though such an event would still take place about a billion years into the future,” Fox said.
Fox and his collaborators will work with Hubble to build a larger selection of surviving companion stars from other supernovae, giving SN 2013ge some company back.
“There is great potential beyond just understanding the supernova itself. Since we now know that most massive stars in the universe are formed in binary pairs, observations of surviving companion stars are necessary to help understand the details of binary formation, material exchange, and co-C ‘is an exciting time to study the stars. ” said Fox.
“It is especially important for us to understand the life cycle of massive stars because all the heavy elements are forged in their core and through their supernovae. These elements make up much of the observable universe, including life as we know it,” added co-author Alex Filippenko. From the University of California at Berkeley.