SNR 0519-69.0
Credit: X-ray: NASA/CXC/GSFC/B. J. Williams et al.; Optical: NASA/ESA/STScI
JPEG (431.1 kb)-Large JPEG (3.1 MB)-Tiff (8.7 MB)-
Credit: X-ray: NASA/CXC/GSFC/B. J. Williams et al.; Optical: NASA/ESA/STScI
JPEG (431.1 kb)-Large JPEG (3.1 MB)-Tiff (8.7 MB)-
While astronomers have seen the debris from scores of exploded stars
in the Milky Way and nearby galaxies, it is often difficult to determine
the timeline of the star’s demise. By studying the spectacular remains of a supernova in a neighboring galaxy using NASA telescopes, a team of astronomers has found enough clues to help wind back the clock.
The supernova remnant called SNR 0519-69.0 (SNR 0519 for short) is the debris from an explosion of a white dwarf star.
After reaching a critical mass, either by pulling matter from a
companion star or merging with another white dwarf, the star underwent a
thermonuclear explosion and was destroyed. Scientists use this type of
supernova, called a Type Ia,
for a wide range of scientific studies ranging from studies of
thermonuclear explosions to measuring distances to galaxies across
billions of light-years.
SNR 0519 is located in the Large Magellanic Cloud, a small galaxy 160,000 light-years from Earth. This composite image shows X-ray data from NASA’s Chandra X-ray Observatory and optical data
from NASA’s Hubble Space Telescope. X-rays from SNR 0519 with low,
medium and high energies are shown in green, blue, and purple
respectively, with some of these colors overlapping to appear white.
Optical data shows the perimeter of the remnant in red and stars around
the remnant in white.
Astronomers combined the data from Chandra and Hubble with data from NASA’s retired Spitzer Space telescope
to determine how long ago the star in SNR 0519 exploded and learn about
the environment the supernova occurred in. This data provides
scientists a chance to “rewind” the movie of the stellar evolution that
has played out since and figure out when it got started.
The researchers compared Hubble images from 2010, 2011, and 2020 to
measure the speeds of material in the blast wave from the explosion,
which range from about 3.8 million to 5.5 million miles (9 million
kilometers) per hour. If the speed was toward the upper end of those
estimated speeds, the astronomers determined that light from the
explosion would have reached Earth about 670 years ago, or during the
Hundred Years’ War between England and France and the height of the Ming
dynasty in China.
However, it’s likely that the material has slowed down since the
initial explosion and that the explosion happened more recently than 670
years ago. The Chandra and Spitzer data provide clues that this is the
case. Astronomers found the brightest regions in X-rays of the remnant
are where the slowest-moving material is located, and no X-ray emission
is associated with the fastest-moving material.
These results imply that some of the blast wave has crashed into
dense gas around the remnant, causing it to slow down as it traveled.
Astronomers may use additional observations with Hubble to determine
more precisely when the time of the star’s demise should truly be set.
A paper describing these results was published in the August issue of The Astrophysical Journal, and a preprint is available here.
The authors of the paper are Brian Williams (NASA’s Goddard Space
Flight Center (GSFC) in Greenbelt, Maryland); Parviz Ghavamian (Towson
University, Towson, Maryland); Ivo Seitenzahl (University of New South
Wales, Australian Defence Force Academy, Canberra, Australia); Stephen
Reynolds (North Carolina State University (NCSU), Raleigh, NC);
Kazimierz Borkowski (North Carolina State University, Raleigh, NC) and
Robert Petre (GSFC). NASA's Marshall Space Flight Center manages the
Chandra program. The Smithsonian Astrophysical Observatory's Chandra
X-ray Center controls science operations from Cambridge, Massachusetts,
and flight operations from Burlington, Massachusetts.
