Discovery after Discovery: Webb Amazes Us Again With Dust in Two Supernovae
Article by: Andacs Robert Eugen, on 08 July 2023, at 09:35 am PDT
Researchers using NASA's James Webb Space Telescope have made significant progress in unraveling the mystery of dust in early galaxies. By observing two Type II supernovae, namely Supernova 2004et (SN 2004et) and Supernova 2017eaw (SN 2017eaw), scientists have discovered substantial amounts of dust within the ejected material from these celestial events. These findings support the theory that supernovae played a pivotal role in supplying dust to the early universe.
Dust serves as a fundamental building block for various entities in our cosmos, especially planets. As dust spreads through space from dying stars, it carries essential elements necessary for the formation of future stars and their planetary systems. The origin of this dust has puzzled astronomers for decades. One significant source could be supernovae, where the explosion of dying stars leads to the expansion and cooling of leftover gases, eventually giving rise to dust.
Lead author Melissa Shahbandeh, affiliated with Johns Hopkins University and the Space Telescope Science Institute in Baltimore, Maryland, explains, "Direct evidence of this phenomenon has been scarce until now, as our capabilities have only allowed us to study the dust population in one relatively nearby supernova to date – Supernova 1987A, located 170,000 light-years away from Earth. Detecting this dust becomes possible only at mid-infrared wavelengths, provided we possess sufficient sensitivity."
For supernovae located beyond the proximity of SN 1987A, such as SN 2004et and SN 2017eaw in NGC 6946, approximately 22 million light-years away, the unique combination of wavelength coverage and remarkable sensitivity can only be achieved using Webb's MIRI (Mid-Infrared Instrument).
These ground-breaking observations with the Webb telescope mark a significant advancement in studying dust production from supernovae since the detection of newly formed dust in SN 1987A using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope nearly a decade ago.
One particularly intriguing outcome of the study is not just the detection of dust but the substantial amount found at this early stage in the supernova's lifecycle. In the case of SN 2004et, researchers identified over 5,000 Earth masses of dust.
Program lead Ori Fox from the Space Telescope Science Institute adds, "When we examine the calculations regarding the amount of dust observed in SN 2004et, especially when considering its age, it rivals the measurements obtained from SN 1987A. It represents the highest dust mass detected in supernovae since SN 1987A."
Observations have revealed that young distant galaxies contain abundant dust. However, these galaxies are not old enough for intermediate-mass stars like the Sun to have contributed to the dust through their aging process. It is possible that more massive, short-lived stars perished early enough and in sufficient numbers to generate such a substantial amount of dust.
While it is confirmed that supernovae produce dust, the question has remained regarding the survivability of this dust amidst the internal shocks occurring in the aftermath of the explosion. The presence of significant dust at this stage in the lifespans of SN 2004et and SN 2017eaw suggests that dust can indeed survive the shockwave. This serves as evidence that supernovae play a crucial role as essential dust factories.
Researchers also highlight that the current estimations of dust mass may only scratch the surface. While the Webb telescope has enabled the measurement of cooler dust than ever before, there could be undetected, colder dust emitting radiation in the electromagnetic spectrum, concealed by the outermost layers of dust.
The researchers emphasize that these new findings merely provide a glimpse into the enhanced research capabilities of studying supernovae and their dust production using the Webb telescope. They look forward to future innovative approaches from fellow researchers in working with these dusty supernovae.
SN 2004et and SN 2017eaw represent the initial targets in a program comprising five objects. The observations were conducted as part of the Webb General Observer program 2666, with the research paper published in the Monthly Notices of the Royal Astronomical Society on July 5.