A dust factory has been spotted in the center of the Milky Way Galaxy. This formation was likely the result of a supernova that took place in the distant past.
Sagittarius A East is a supernova remnant, located near the center of our galaxy, that was formed during an eruption that would have been seen on Earth 10,000 years ago, if astronomers had been around to witness the event.
The observation was seen by astronomers utilizing the Faint Object Infrared Camera Telescope (Forcast) carried aboard a specially-designed Boeing 747 aircraft, the Stratospheric Observatory for Infrared Astronomy (Sofia). This is the largest airborne astronomical observatory in the world.
Nearly all of the elements that make up planets, asteroids and life were first forged in powerful supernova explosions. Well-known astronomer Carl Sagan of the Jet Propulsion Laboratory was fond of saying that we are all made of "star stuff."
"Dust itself is very important because it's the stuff that forms stars and planets, like the sun and Earth, respectively, so to know where it comes from is an important question," Ryan Lau from Cornell University said.
Dust is recorded in many galaxies, including some seen as they were far back in time, when such material is believed to have been rare. This new finding suggests that supernovae, the explosive deaths of massive stars, are likely the sources of this ancient dust. Another theory held that dust was formed by rising of material from within stars that have not become supernovae. However, this process was thought to be too slow to account for observations seen in early galaxies.
"Finding this surviving dust is surprising to me because when I think of a supernova, I imagine a very harsh, violent environment that is very inhospitable to dust and other things that happen to be caught in the explosion," Lau said.
Super-massive stars live for just a short period of time, and when these monster stars explode, they spread heavy elements like carbon, iron and silicon to space, where the atoms and molecules combine to form dust. However, many astronomers calculate that nearly all of this material would be destroyed as a reverse shockwave from the explosion bounces off cold gas and is reflected back onto the dust. The study showed up to 20 percent of that material could survive such an encounter.
No ground-based telescope can observe objects in space in far-infrared light, since those wavelengths of electromagnetic radiation are absorbed by water vapor in the atmosphere. In addition, no orbiting observatory is capable of viewing astronomical bodies in these frequencies, making it necessary to use Forcast and Sophia for the study.
Optical observations of the center of the Milky Way Galaxy are blocked by dust, which has long presented a challenge to those researchers working to understand the processes occurring there.
Observation and examination of the dust cloud at the center of the Milky Way Galaxy was detailed in the journal Science Express.
