From NASA/ESA Hubble Telescope: “Researchers Rewind the Clock to Calculate Age and Site of Supernova Blast”

NASA/ESA Hubble Telescope


From NASA/ESA Hubble Telescope

January 14, 2021

Donna Weaver
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493
dweaver@stsci.edu
Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu

John Banovetz
Purdue University, West Lafayette, Indiana
jbanovet@purdue.edu

Danny Milisavljevic
Purdue University, West Lafayette, Indiana
dmilisav@purdue.edu

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Supernova Remnant 1E 0102 Compass


About This Video
Hubble Time-Lapse Video Reveals Supernova Remnant Expansion
This time-lapse video shows the movement of a supernova remnant—the gaseous remains of an exploded star—that erupted approximately 1,700 years ago.
The stellar corpse, a supernova remnant named 1E 0102.2-7219, met its demise in the Small Magellanic Cloud, a satellite galaxy of our Milky Way.
The movie’s opening frame shows ribbons of glowing gaseous clumps that make up the remnant. Because the gaseous knots are moving at different speeds and directions from the supernova explosion, in this composition those moving toward us are colored blue and the ones moving away are colored red.
The video then toggles between two black-and-white images of the remnant, taken 10 years apart, revealing subtle shifts in the ejecta’s expansion over time. To show that expansion in more detail, the movie ends with two close-ups of the knots’ movement.
Researchers plumbed the Hubble archive for visible-light images of the supernova remnant. They analyzed the data to calculate a more accurate estimate of the age and center of the supernova blast.
The Small Magellanic Cloud, located roughly 200,000 light-years away, is visible in the southern hemisphere.
This color image is a blend of exposures taken in 2014 by the Wide Field Camera 3. The black-and-white images were taken in 2003 and 2013 by the Advanced Camera for Surveys.

NASA/ESA Hubble WFC3

NASA Hubble Advanced Camera for Surveys.

Credits: NASA, ESA, A. Pagan (STScI), J. Banovetz and D. Milisavljevic (Purdue University)

Summary

Light from Supernova Blast Reached Earth 1,700 Years Ago

Sometime during the third century, a brilliant burst of light from the explosion of a massive star was visible from Earth.

If the supernova blast had flashed over the northern hemisphere, it might have been considered an evil omen. At that time, Western Civilization was in upheaval. The Roman Empire was beginning to crumble. An emperor was assassinated, followed by political upheavals, civil wars, and barbarian attacks.

But the violent supernova death could only be seen in the southern skies. The blast occurred in the nearby satellite galaxy, the Small Magellanic Cloud. No record exists of the titanic event. However, like the smoke and ash drifting across the sky after an aerial fireworks blast, the supernova left behind a cloud of debris that is still rapidly expanding today. This cloud provides forensic evidence for astronomical detectives to retrace the explosion.

Astronomers sifting through Hubble observations of the supernova remnant, taken 10 years apart, have calculated the cloud’s expansion rate. Analyzing the data was like rewinding a movie. The researchers traced the path of all the debris flung from the explosion back to the point in space where the doomed star blew apart. Their analysis reveals that the light from the exploded star reached Earth 1,700 years ago.

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Astronomers are winding back the clock on the expanding remains of a nearby, exploded star. By using NASA’s Hubble Space Telescope, they retraced the speedy shrapnel from the blast to calculate a more accurate estimate of the location and time of the stellar detonation.

The victim is a star that exploded long ago in the Small Magellanic Cloud, a satellite galaxy to our Milky Way.

smc

Small Magellanic Cloud. 10 November 2005. NASA/ESA Hubble and Digitized Sky Survey 2.

The doomed star left behind an expanding, gaseous corpse, a supernova remnant named 1E 0102.2-7219, which NASA’s Einstein Observatory first discovered in X-rays.

NASA Einstein Observatory spacecraft, launched on November 13, 1978; re-entered the Earth’s atmosphere and burned up on March 25, 1982.

Like detectives, researchers sifted through archival images taken by Hubble, analyzing visible-light observations made 10 years apart.

The research team, led by John Banovetz and Danny Milisavljevic of Purdue University in West Lafayette, Indiana, measured the velocities of 45 tadpole-shaped, oxygen-rich clumps of ejecta flung by the supernova blast. Ionized oxygen is an excellent tracer because it glows brightest in visible light.

To calculate an accurate explosion age, the astronomers picked the 22 fastest moving ejecta clumps, or knots. The researchers determined that these targets were the least likely to have been slowed down by passage through interstellar material. They then traced the knots’ motion backward until the ejecta coalesced at one point, identifying the explosion site. Once that was known, they could calculate how long it took the speedy knots to travel from the explosion center to their current location.

According to their estimate, light from the blast arrived at Earth 1,700 years ago, during the decline of the Roman Empire. However, the supernova would only have been visible to inhabitants of Earth’s southern hemisphere. Unfortunately, there are no known records of this titanic event.

The researchers’ results differ from previous observations of the supernova’s blast site and age. Earlier studies, for example, arrived at explosion ages of 2,000 and 1,000 years ago. However, Banovetz and Milisavljevic say their analysis is more robust.

“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) [above],” Milisavljevic said.

Hubble WFPC2 no longer in service.

“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 also took advantage of the sharp ACS images in selecting which ejecta clumps to analyze. In prior studies, researchers averaged the speed of all of the gaseous debris to calculate an explosion age. However, the ACS data revealed regions where the ejecta slowed down because it was slamming into denser material shed by the star before it exploded as a supernova. Researchers didn’t include those knots in the sample. They needed the ejecta that best reflected their original velocities from the explosion, using them to determine an accurate age estimate of the supernova blast.

Hubble also clocked the speed of a suspected neutron star—the crushed core of the doomed star—that was ejected from the blast. Based on their estimates, the neutron star must be moving at more than 2 million miles per hour from the center of the explosion to have arrived at its current position. The suspected neutron star was identified in observations with the European Southern Observatory’s Very Large Telescope in Chile, in combination with data from NASA’s Chandra X-ray Observatory.

ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
•KUEYEN (UT2; The Moon ),
•MELIPAL (UT3; The Southern Cross ), and
•YEPUN (UT4; Venus – as evening star).
elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

NASA Chandra X-ray Space Telescope

“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 said. “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 may 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 said.

Banovetz will present the team’s findings Jan. 14 at the American Astronomical Society’s winter meeting.

Science paper:
The Center of Expansion and Age of the Oxygen-rich Supernova Remnant 1E 0102.2-7219.

See the full article here .


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Major Instrumentation

Wide Field Camera 3 [WFC3]

NASA/ESA Hubble WFC3

Advanced Camera for Surveys [ACS]

NASA Hubble Advanced Camera for Surveys.

Cosmic Origins Spectrograph [COS]

NASA Hubble Cosmic Origins Spectrograph.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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