NASA Chandra Image: Companion star survives supernova blast

Credit X-ray: NASA /CXC /SAO /F.Seward et al; Optical: NOAO /CTIO /MCELS, DSS

When a massive star runs out fuel, it collapses and explodes as a supernova.

Although these explosions are extremely powerful, it is possible for a companion star to endure the blast.

A team of astronomers using NASA's Chandra X-ray Observatory and other telescopes has found evidence for one of these survivors.

This hardy star is in a stellar explosion's debris field, also called its supernova remnant, located in an HII region called DEM L241.

An HII region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms (HI) to form clouds of ionized hydrogen (HII).

This HII region is located in the Large Magellanic Cloud, a small companion galaxy to the Milky Way.

A new composite image of DEM L241 contains Chandra data (purple) that outlines the supernova remnant.

The remnant remains hot and therefore X-ray bright for thousands of years after the original explosion occurred.

Also included in this image are optical data from the Magellanic Cloud Emission Line Survey (MCELS) taken from ground-based telescopes in Chile (yellow and cyan), which trace the HII emission produced by DEM L241.

Additional optical data from the Digitized Sky Survey (white) are also included, showing stars in the field.

R. Davies, K. Elliott, and J. Meaburn, whose last initials were combined to give the object the first half of its name, first mapped DEM L241 in 1976.

The recent data from Chandra revealed the presence of a point-like X-ray source at the same location as a young massive star within DEM L241's supernova remnant.

Astronomers can look at the details of the Chandra data to glean important clues about the nature of X-ray sources.

For example, how bright the X-rays are, how they change over time, and how they are distributed across the range of energy that Chandra observes.

In this case, the data suggest that the point-like source is one component of a binary star system.

In such a celestial pair, either a neutron star or black hole (formed when the star went supernova) is in orbit with a star much larger than our Sun.

As they orbit one another, the dense neutron star or black hole pulls material away its companion star through the wind of particles that flows away from its surface.

If this result is confirmed, DEM L241 would be only the third binary containing both a massive star and a neutron star or black hole ever found in the aftermath of a supernova.

More information: A paper describing these results is available online and was published in the November 10, 2012, issue of The Astrophysical Journal: dx.doi.org/10.1088/0004-637X/759/2/123

A blast from its past dates the youngest neutron-star binary

The youngest member of an important class of objects in space has been found by a team that includes Penn State Distinguished Professor of Astronomy and Astrophysics Niel Brandt. 

This composite image shows the energies streaming toward Earth from this object -- X-rays in blue and the radio emission in purple.

These energy detections have been overlaid in this image on an optical field of view from the Digitized Sky Survey. 

This discovery allows scientists to study a critical phase after a supernova and the birth of a neutron star. 

Credit: X-ray: NASA/CXC /Univ. of Wisconsin-Madison /S. Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA

X-rays streaming toward Earth from the region near a neutron star that is cannibalizing its companion star have revealed the pair to be the youngest "X-ray binary" yet known.

The discovery by a team that includes a Penn State astronomer is being published in this week's issue of the The Astrophysical Journal.

The team discovered the age of this record-breaking pair, named Circinus X-1, by using data from NASA's Chandra X-ray Observatory, which revealed faint remnants of the supernova explosion that created the neutron star.

"I have been perplexed by the unusually strong evolution of the orbit of Circinus X-1 since my graduate-school days," said Niel Brandt, Distinguished Professor of Astronomy and Astrophysics.

"The discovery now of this system's youth provides a satisfying explanation for why its orbit evolves so strongly—because the system likely still is settling down after its violent birth."

The research team, which was led by Sebastian Heinz at the University of Wisconsin-Madison, determined that Circinus X-1 is less than 4,600 years old.

"X-ray binaries provide us with opportunities to study matter under extreme conditions that would be impossible to recreate in a laboratory," Heinz said.

"For the first time, we can study a newly minted neutron star in an X-ray binary system."

This is an artist's conception of the life of X-ray binary systems and the young and turbulent history of Circinus X-1, which formed in a supernova explosion less than 4,600 years ago, approximately 500 B.C.E., making it the youngest known X-ray binary. 

Credit: University of Wisconsin-Madison

X-ray binaries are star systems made up of two parts: a compact stellar remnant—either a neutron star or a black hole; and a companion star—a normal star like our Sun.

The new discovery, made in parallel with a radio telescope in Australia, provides scientists with unique insight into the formation of neutron stars and supernovas, and the effect of the supernova's explosion on a nearby companion star.

As the two objects orbit one another, the neutron star or black hole pulls in gas from the companion star, heating the gas to millions of degrees, producing intense X-ray radiation, and making these star systems some of the brightest X-ray sources in the sky.

To determine the age of Circinus X-1, the astronomers needed to examine the material around the orbiting pair of stars.

However, the overwhelming brightness of the neutron star made it too difficult for researchers to observe that interstellar gas.

The team recently caught a break, however, when they observed the neutron star in a very faint state—dim enough for scientists to detect the X-rays from the supernova shock wave that plowed through the surrounding interstellar gas.

Read the full story here

Antartica BLAST sub-millimeter Telescope: Balloon-mounted

NASA's balloon-carried BLAST sub-millimeter telescope is hoisted into launch position on Dec. 25, 2012, at McMurdo Station in Antarctica on a mission to peer into the cosmos.

CREDIT: NASA/Wallops Flight Facility

A giant helium balloon is slowly drifting above Antarctica, about 22 miles (36 kilometers) up.

Launched on Tuesday (Dec. 25) from the National Science Foundation's Long Duration Balloon (LDB) facility on Earth's southernmost continent, it carries a sensitive telescope that measures sub-millimeter light waves from stellar nurseries in our Milky Way.

"Christmas launch!" wrote officials with NASA's Wallops Flight Facility, which oversees the agency's balloon research program, in a Twitter post yesterday. "BLAST launched today from McMurdo Station, Antarctica."

This is the fifth and final mission for BLAST, short for the Balloon-borne Large-Aperture Submillimeter Telescope, and mission designers hope it will reveal why so few stars are born in our galaxy.