NC State astrophysicist discovers youngest known supernova in Milky Way

May 14, 2008

A North Carolina State University researcher has discovered the youngest known supernova in our galaxy. Estimated at a mere 140 years old, this celestial whippersnapper is at least 200 years younger than the next oldest known supernova, and its discovery may pave the way to a greater understanding of exploding stars.

Dr. Stephen Reynolds, an astrophysicist at NC State, led a team of researchers who suspected that a celestial object known as G1.9+0.3 was a very young supernova remnant. They examined images of the object that were taken in 2007 by NASA's Chandra X-Ray Observatory and compared these images to those taken of the same object in 1985 by the National Radio Astronomy Observatory's Very Large Array radio telescope.

Not only did the Chandra images confirm Reynolds' suspicions that the object was a young supernova remnant, but the scientists discovered that the supernova had increased in size by 16 percent in just 22 years, suggesting that the initial explosion had occurred only 140 years ago - or less if the rate of explosion had been slowing.

The results will appear in the June 10 edition of Astrophysical Journal Letters.

Supernovae are exploding stars, and act as the "engines" that drive the life cycles of galaxies. A supernova explosion disperses heavy metals, cosmic rays, and high-energy particles throughout the galaxy, aiding in the formation of new stars. In fact, a supernova explosion may have helped prod our own solar system into existence.

The brightness of supernovae can easily be obscured from optical telescopes by large amounts of interstellar gas and dust, rendering them all but invisible to astronomers. X-ray and radio telescopes, however, can detect the radio waves and high energy X-rays that supernovae emit, enabling us to "see" even highly obscured explosions.

Reynolds says that the G1.9+0.3 supernova has the largest obscuration of any known galactic supernova object.

"If not for all the interstellar 'gunk' between us and this object, people would have seen this supernova as a new star in the constellation Sagittarius in the years around 1870 to 1900," Reynolds adds.

"Normally, we deal with older remnants and have to work very hard to see even tiny changes. This supernova is getting brighter, which means it's still on its way up -- studying it will go a long way toward filling in gaps in our knowledge of these events and their effect on galaxies."
-end-
Note to editors: An abstract of the paper follows.

"The Youngest Galactic Supernova Remnant G1.9+0.3"
Authors: Stephen Reynolds, Kazimierz Borkowski, North Carolina State University, et al.
Published: June 10, 2008 in Astrophysical Journal Letters

Abstract:

Our 50 ks Chandra observation of the small radio supernova remnant (SNR) G1.9+0.3 shows a complete shell structure with strong bilateral symmetry, about 10000 in diameter. The radio morphology is also shell-like, but only about 8400 in diameter, based on observations made in 1985. We attribute the size difference to expansion between 1985 and our Chandra observations of 2007. Expansion is confirmed in comparing radio images from 1985 and 2008. We deduce that G1.9+0.3 is of order 100 years old . the youngest supernova remnant in the Galaxy. Based on a very high absorbing column density of 5:5£1022 cm-2, we place G1.9+0.3 near the Galactic Center, at a distance of about 8.5 kpc, where the mean remnant radius would be about 2 pc, and the required expansion speed about 14;000 km s-1. The X-ray spectrum is featureless and well-described by the exponentially cut off synchrotron model srcut. With the radio flux at 1 GHz fixed at 0.9 Jy, we find a spectral index of 0:65 and a rolloff frequency of 1:4£1018 Hz. The implied characteristic rolloff electron energy of about 94(B=10 ¹G)-1=2 TeV is the highest ever reported for a shell supernova remnant. It can easily be reached by standard diffusive shock acceleration, given the very high shock velocities; it can be well described by either age-limited or synchrotron-loss-limited acceleration. Not only is G1.9+0.3 the youngest known Galactic remnant, it is also only the fourth Galactic X-ray synchrotron-dominated shell supernova remnant.

North Carolina State University

Related Supernova Articles from Brightsurf:

Scientists discover supernova that outshines all others
A supernova at least twice as bright and energetic, and likely much more massive than any yet recorded has been identified by an international team of astronomers, led by the University of Birmingham.

Supernova observation first of its kind using NASA satellite
Their research, detailed in the Monthly Notices of the Royal Astronomical Society, represents the first published findings about a supernova observed using TESS, and add new insights to long-held theories about the elements left behind after a white dwarf star explodes into a supernova.

Astronomers find possible elusive star behind supernova
Astronomers may have finally found a doomed star that seemed to have avoided detection before its explosive death.

Stellar thief is the surviving companion to a supernova
Hubble found the most compelling evidence that some supernovas originate in double-star systems.

Supernova may have 'burped' before exploding
Only by increasing the rate at which telescopes monitor the sky has it been possible to catch more Fast-Evolving Luminous Transients (FELTs) and begin to understand them.

An unusual white dwarf may be a supernova leftover
Astronomers have identified a white dwarf star in our galaxy that may be the leftover remains of a recently discovered type of supernova.

Researchers show how to make your own supernova
Researchers from the University of Oxford are using the largest, most intense lasers on the planet, to for the first time, show the general public how to recreate the effects of supernovae, in a laboratory.

The big star that couldn't become a supernova
For the first time in history, astronomers have been able to watch as a dying star was reborn as a black hole.

Seeing quadruple: Four images of the same supernova, a rare find
Galaxies bend light through an effect called gravitational lensing that helps astronomers peer deeper into the cosmos.

Explosive material: The making of a supernova
Pre-supernova stars may show signs of instability for months before the big explosion

Read More: Supernova News and Supernova Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.