Artist's concept illustrating Supernova 1987A as the powerful blast wave passes through its outer ring and destroys most of its dust, before the dust re-forms or grows rapidly. SOFIA observations reveal that this dust — a building block of stars and planets — can re-form or grow immediately after the catastrophic damage caused by the supernova’s blast wave. Image credits: NASA/SOFIA/Symbolic Pictures/ The Casadonte Group.
Columbia, MD--Febriuary 11,2019. : Researchers using NASA’s SOFIA airborne telescope have found that cosmic dust, a building block of planets, forms in the wake of a supernova blast wave.
Cosmic dust, a building block of stars and planets, can form in the
wake of a violent stellar explosion called a supernova, according to a
new study using the Stratospheric Observatory for Infrared Astronomy,
SOFIA. These surprising findings provide clues to an astronomical
mystery surrounding cosmic dust.
Dust particles form as dying red giant stars
throw off material and become part of interstellar clouds of various
sizes, densities and temperatures. This cosmic dust is then destroyed by
supernova blast waves, which propagate through space at more than 6,000
miles per second (10,000 km/sec)!
Supernova explosions are among the most powerful events in the
universe, with a peak brightness equivalent to the light from billions
of individual stars. The explosion also produces a blast wave that
destroys almost everything in its path, including dust in the
surrounding interstellar medium, the space between the stars. Current
theories predict when a supernova blast sweeps through a region of
space, much of the dust would be destroyed, so there should be little
dust left.
Observations with SOFIA, however, tell a different, mysterious story —
revealing more than 10 times the dust expected. This suggests that dust
is much more abundant in the wake of a blast wave than theories
estimate.
The new study is based on observations of a nearby supernova explosion, called Supernova 1987A.
When it was discovered in 1987, it was one of the brightest supernovae
seen in 400 years! Due to its close proximity, astronomers have been
able to monitor its impact on the surrounding environment continuously
for the past 30 years.
SOFIA’s observations of the iconic supernova suggest dust may
actually be forming in the wake of the powerful blast wave. These
results are helping astronomers solve the mystery surrounding the
abundance of dust in our galaxy.
“We already knew about the slow-moving dust in the heart of 1987A,”
said Mikako Matsuura, a senior lecturer at Cardiff University, in the
United Kingdom, and the lead author on the paper. “It formed from the
heavy elements created in the core of the dead star. But the SOFIA
observations tell us something new about a completely unexpected dust
population.”
The observations were published in a recent issue of Monthly Notices of the Royal Astronomical Society.
Supernova 1987A has a distinctive set of rings
that are part of a cavity created in an earlier, pre-explosion phase of
the star’s evolution. The fast-expanding blast wave has passed through
these ring structures. Astronomers thought that any dust particles in
these rings would have been destroyed, but recent observations from
SOFIA show emission consistent with a growing population of dust in the
rings. The results indicate that dust particles can re-form or grow
rapidly, even after the catastrophic damage caused during the passage of
the blast wave, suggesting that although this might be the end of a
chapter in the life cycle of dust, it does not appear to be the end of
the story.
The dust detected by SOFIA could result from either significant
growth of the existing dust particles or the formation of a new dust
population. These new observations compel astronomers to consider the
possibility that the post-blast environment might be ready to form or
re-form dust immediately after the blast wave passes — a new clue that
may be pivotal in resolving the discrepancy between dust destruction
models and observations.
From ground-based telescopes on Earth, observing cosmic dust
particles in the infrared is difficult — or impossible — due to strong
absorption, primarily from water and carbon dioxide in the Earth’s
atmosphere. By flying above most of the obscuring molecules, the
airborne observatory SOFIA provides access to portions of the infrared
spectrum not available from the ground. In particular, SOFIA’s Faint
Object infraRed CAmera for the SOFIA Telescope (FORCAST) is a powerful
instrument for understanding warm dust in particular.
“FORCAST is the only instrument that can observe at these critical
wavelengths and detect this newly-forming population of warm dust,” said
James De Buizer, the USRA manager for science operations at the SOFIA
Science Center and co-author on the study. “We plan to continue
monitoring with FORCAST to gain more insight into dust creation and
evolution in supernova remnants.”
In the future, NASA’s James Webb Space Telescope will examine this dust in further detail, looking for clues about its origins and composition.
SOFIA is a Boeing 747SP jetliner modified to carry a 106-inch
diameter telescope. It is a joint project of NASA and the German
Aerospace Center, DLR. NASA’s Ames Research Center in California’s
Silicon Valley manages the SOFIA program, science and mission operations
in cooperation with the Universities Space Research Association, or
USRA, headquartered in Columbia, Maryland, and the German SOFIA
Institute (DSI) at the University of Stuttgart. The aircraft is
maintained and operated from NASA’s Armstrong Flight Research Center
Hangar 703, in Palmdale, California.
Contact:
Suraiya Farukhi
Director, External Communications
sfarukhi@usra.edu
410-740-6224
