Swift, Chandra explore a youthful 'star wreck'

Mar 15, 2013 by Francis Reddy
This composite of supernova remnant G306.3-0.9 merges Chandra X-ray observations (blue), infrared data acquired by the Spitzer Space Telescope (red and cyan) and radio observations (purple) from the Australia Telescope Compact Array. The image is 20 arcminutes across, which corresponds to 150 light-years at the remnant's estimated distance. Credit: X-ray: NASA/CXC/Univ. of Michigan/M. Reynolds et al; Infrared: NASA/JPL-Caltech; Radio: CSIRO/ATNF/ATCA

(Phys.org) —While performing an extensive X-ray survey of our galaxy's central regions, NASA's Swift satellite has uncovered the previously unknown remains of a shattered star. Designated G306.3.9 after the coordinates of its sky position, the new object ranks among the youngest-known supernova remnants in our Milky Way galaxy.

"Astronomers have previously cataloged more than 300 supernova remnants in the galaxy," said lead scientist Mark Reynolds, a at the University of Michigan in Ann Arbor. "Our analysis indicates that G306.3.9 is likely less than 2,500 years old, making it one of the 20 youngest remnants identified."

Astronomers estimate that a occurs once or twice a century in the Milky Way. The expanding and hot stellar debris slowly dissipate over hundreds of thousands of years, eventually mixing with and becoming indistinguishable from .

Like fresh evidence at a crime scene, young supernova remnants give astronomers the best opportunity for understanding the nature of the original star and the details of its demise.

Supernova remnants emit energy across the , from radio to , and important clues can be found in each . X-ray observations figure prominently in revealing the motion of the expanding debris, its chemical content, and its interaction with the interstellar environment, but fade out in X-ray light after 10,000 years. Indeed, only half of those known in the have been detected in X-rays at all.

This image from Swift’s X-ray Telescope was taken on Feb. 22, 2011, as part of the Galactic Plane Survey. The dots in the image indicate where X-rays struck the detector. Despite this short 8.5-minute exposure, the extended circular patch of G306.3–0.9 stands out. The image is 25.5 arcminutes across. Credit: NASA/Swift/Stefan Immler

Reynolds leads the Swift Galactic Plane Survey, a project to image a two-degree-wide strip along the Milky Way's central plane at X-ray and ultraviolet energies at the same time. Imaging began in 2011 and is expected to complete this summer.

"The Swift survey leverages previously compiled by NASA's and extends it into higher energies," said team member Michael Siegel, a research associate at the Swift Mission Operations Center (MOC) in State College, Pa., which is operated by Penn State University. "The infrared and X-ray surveys complement each other because light at these energies penetrates dust clouds in the galactic plane, while the ultraviolet is largely extinguished."

A wider view places G306.3–0.9 in context with star-formation regions in southern Centaurus. Chandra X-ray observations (blue), Spitzer infrared data (red, cyan), and radio observations (purple) from the Australia Telescope Compact Array are merged in this composite. The image is one degree across, which corresponds to 450 light-years at the remnant's estimated distance. Credit: X-ray: NASA/CXC/Univ. of Michigan/M. Reynolds et al; Infrared: NASA/JPL-Caltech; Radio: CSIRO/ATNF/ATCA

On Feb. 22, 2011, Swift imaged a survey field near the southern border of the constellation Centaurus. Although nothing unusual appeared in the ultraviolet exposure, the X-ray image revealed an extended, semi-circular source reminiscent of a supernova remnant. A search of archival data revealed counterparts in Spitzer infrared imagery and in radio data from the Molonglo Observatory Synthesis Telescope in Australia.

To further investigate the object, the team followed up with an 83-minute exposure using NASA's Chandra X-ray Observatory and additional radio observations from the Australia Telescope Compact Array (ATCA), located near the town of Narrabri in New South Wales.

"The fantastic sensitivity of ATCA has enabled us to image what, at radio wavelengths, turns out to be the dimmest remnant we have ever seen in our galaxy," said team member Cleo Loi, an undergraduate student at the University of Sydney who led the analysis of the radio observations.

A paper describing the team's findings will appear in an upcoming edition of The Astrophysical Journal and was published online on Friday.

Using an estimated distance of 26,000 light-years for G306.3.9, the scientists determined that the explosion's shock wave is racing through space at about 1.5 million mph (2.4 million km/h). The Chandra observations reveal the presence of iron, neon, silicon and sulfur at temperatures exceeding 50 million degrees F (28 million C), a reminder not only of the energies involved but of the role supernovae play in seeding the galaxy with heavy elements produced in the hearts of massive stars.

"We don't yet have enough information to determine what type of supernova this was and therefore what type of star exploded, but we've planned a further Chandra observation to improve the picture," said coauthor Jamie Kennea, also a researcher at the Swift MOC. "We see no compelling evidence that the explosion formed a neutron star, and this is something we hope can be determined one way or the other by future work."

Explore further: New mass map of a distant galaxy cluster is the most precise yet

Related Stories

Remnant of an explosion with a powerful kick?

Feb 02, 2012

(PhysOrg.com) -- Vital clues about the devastating ends to the lives of massive stars can be found by studying the aftermath of their explosions. In its more than twelve years of science operations, NASA's ...

Image: A supernova cocoon breakthrough

Jul 10, 2012

(Phys.org) -- Using observations from NASA's Chandra X-ray Observatory, researchers have obtained the first X-ray evidence of a supernova shock wave breaking through a cocoon of gas surrounding the star that ...

Was Kepler's supernova unusually powerful?

Sep 11, 2012

(Phys.org)—In 1604, a new star appeared in the night sky that was much brighter than Jupiter and dimmed over several weeks. This event was witnessed by sky watchers including the famous astronomer Johannes ...

X-rays discovered from young supernova remnant

Jul 31, 2012

(Phys.org) -- Over fifty years ago, a supernova was discovered in M83, a spiral galaxy about 15 million light years from Earth. Astronomers have used NASA's Chandra X-ray Observatory to make the first detection ...

Detective astronomers unearth hidden celestial gem

Jun 10, 2008

ESA’s orbiting X-ray observatory XMM-Newton has re-discovered an ignored celestial gem. The object in question is one of the youngest and brightest supernova remnants in the Milky Way, the corpse of a star ...

Recommended for you

Image: Chandra's view of the Tycho Supernova remnant

2 hours ago

More than four centuries after Danish astronomer Tycho Brahe first observed the supernova that bears his name, the supernova remnant it created is now a bright source of X-rays. The supersonic expansion of ...

Satellite galaxies put astronomers in a spin

Jul 24, 2014

An international team of researchers, led by astronomers at the Observatoire Astronomique de Strasbourg (CNRS/Université de Strasbourg), has studied 380 galaxies and shown that their small satellite galaxies almost always ...

Video: The diversity of habitable zones and the planets

Jul 24, 2014

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable ...

User comments : 0