Astronomers are winding back the clock on the broadening remains of a close-by, took off star. By utilizing NASA’s Hubble Space Telescope, they backtracked the fast shrapnel from the blast to compute a more precise price quote of the place and time of the outstanding detonation.
The victim is a star that took off long earlier in the Small Magellanic Cloud, a satellite galaxy to our Milky Way. The doomed star left a broadening, gaseous remains, a supernova residue called 1E 0102.2-7219, which NASA’s Einstein Observatory very first found in X-rays. Like investigators, scientists sorted through archival images taken by Hubble, examining visible-light observations made 10 years apart.
The research study group, led by John Banovetz and Danny Milisavljevic of Purdue University in West Lafayette, Indiana, determined the speeds of 45 tadpole-shaped, oxygen-rich clumps of ejecta flung by the supernova blast. Ionized oxygen is an exceptional tracer due to the fact that it shines brightest in noticeable light.
To compute a precise surge age, the astronomers chose the 22 fastest moving ejecta clumps, or knots. The scientists identified that these targets were the least most likely to have actually been decreased by passage through interstellar product. They then traced the knots’ movement backwards up until the ejecta coalesced at one point, determining the surge website. Once that was understood, they might compute for how long it took the fast knots to take a trip from the surge center to their present place.
According to their price quote, light from the blast came to Earth 1,700 years earlier, throughout the decrease of the Roman Empire. However, the supernova would just have actually shown up to occupants of Earth’s southern hemisphere. Unfortunately, there are no recognized records of this titanic occasion.
The scientists’ outcomes vary from previous observations of the supernova’s blast website and age. Earlier research studies, for instance, came to surge ages of 2,000 and 1,000 years earlier. However, Banovetz and Milisavljevic state their analysis is more robust.
This time-lapse video reveals the motion of a supernova residue—the gaseous remains of a took off star—that appeared roughly 1,700 years earlier. The outstanding remains, a supernova residue called 1E 0102.2-7219, satisfied its death in the Small Magellanic Cloud, a satellite galaxy of our Milky Way. The film’s opening frame reveals ribbons of radiant gaseous clumps that comprise the residue. The video then toggles in between 2 black-and-white pictures of the residue, taken 10 years apart, exposing subtle shifts in the ejecta’s growth with time. Credit: NASA, ESA, A. Pagan (STScI), J. Banovetz and D. Milisavljevic (Purdue University)
“A prior study compared images taken years apart with two different cameras on Hubble, the Wide Field Planetary Camera 2 and the Advanced Camera for Surveys (ACS),” Milisavljevic stated. “But our study compares data taken with the same camera, the ACS, making the comparison much more robust; the knots were much easier to track using the same instrument. It’s a testament to the longevity of Hubble that we could do such a clean comparison of images taken 10 years apart.”
The astronomers likewise made the most of the sharp A/C images in picking which ejecta clumps to evaluate. In previous research studies, scientists balanced the speed of all of the gaseous particles to compute a surge age. However, the ACS information exposed areas where the ejecta decreased due to the fact that it was knocking into denser product shed by the star prior to it took off as a supernova. Researchers didn’t consist of those knots in the sample. They required the ejecta that finest shown their initial speeds from the surge, utilizing them to identify a precise age price quote of the supernova blast.
Hubble likewise clocked the speed of a thought neutron star—the crushed core of the doomed star—that was ejected from the blast. Based on their quotes, the neutron star need to be moving at more than 2 million miles per hour from the center of the surge to have actually reached its present position. The believed neutron star was recognized in observations with the European Southern Observatory’s Very Large Telescope in Chile, in mix with information from NASA’s Chandra X-ray Observatory.
“That is pretty fast and at the extreme end of how fast we think a neutron star can be moving, even if it got a kick from the supernova explosion,” Banovetz stated. “More recent investigations call into question whether the object is actually the surviving neutron star of the supernova explosion. It is potentially just a compact clump of supernova ejecta that has been lit up, and our results generally support this conclusion.”
So the hunt might still be on for the neutron star. “Our study doesn’t solve the mystery, but it gives an estimate of the velocity for the candidate neutron star,” Banovetz stated.
Banovetz provided the group’s findings on January 14, 2021, at the American Astronomical Society’s winter season conference.
The Hubble Space Telescope is a task of worldwide cooperation in between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, handles the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, carries out Hubble science operations. STScI is run for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.