Tag: Chandra X-ray Observatory

NASA Image of the Day for Feb. 6th

Remnant of a Supernova

Remnant of a Supernova

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 Chandra X-ray Observatory has studied many of these supernova remnants sprinkled across the galaxy.

The latest example of this important investigation is Chandra’s new image of the supernova remnant known as G350.1-0.3. This stellar debris field is located some 14,700 light years from the Earth toward the center of the Milky Way.

Evidence from Chandra and from ESA’s XMM-Newton telescope suggest that a compact object within G350.1+0.3 may be the dense core of the star that exploded. The position of this likely neutron star, seen by the arrow pointing to “neutron star” in the inset image, is well away from the center of the X-ray emission. If the supernova explosion occurred near the center of the X-ray emission then the neutron star must have received a powerful kick in the supernova explosion.

Data suggest this supernova remnant, as it appears in the image, is 600 and 1,200 years old. If the estimated location of the explosion is correct, this means the neutron star has been moving at a speed of at least 3 million miles per hour since the explosion.

Another intriguing aspect of G350.1-0.3 is its unusual shape. Many supernova remnants are nearly circular, but G350.1-0.3 is strikingly asymmetrical as seen in the Chandra data in this image (gold). Infrared data from NASA’s Spitzer Space Telescope (light blue) also trace the morphology found by Chandra. Astronomers think that this bizarre shape is due to stellar debris field expanding into a nearby cloud of cold molecular gas.

The age of 600-1,200 years puts the explosion that created G350.1-0.3 in the same time frame as other famous supernovas that formed the Crab and SN 1006 supernova remnants. However, it is unlikely that anyone on Earth would have seen the explosion because of the obscuring gas and dust that lies along our line of sight to the remnant.

These results appeared in the April 10, 2011 issue of The Astrophysical Journal.

Image Credits: X-ray: NASA/CXC/SAO/I. Lovchinsky et al; IR: NASA/JPL-Caltech

NASA Image of the Day for October 14th

Carina Nebula: 14,000+ Stars

The Carina Nebula is a star-forming region in the Sagittarius-Carina arm of the Milky Way that is 7,500 light years from Earth and the Chandra X-Ray Observatory has detected more than 14,000 stars in the region.

Chandra’s X-ray vision provides strong evidence that massive stars have self-destructed in this nearby star-forming region. Firstly, there is an observed deficit of bright X-ray sources in the area known as Trumpler 15, suggesting that some of the massive stars in this cluster were already destroyed in supernova explosions. Trumpler 15 is located in the northern part of the image and is one of ten star clusters in the Carina complex.

The detection of six possible neutron stars, the dense cores often left behind after stars explode in supernovas, provides additional evidence that supernova activity is increasing up in Carina. Previous observations had only detected one neutron star in Carina.

Image Credit: NASA/CXC/Penn State/L. Townsley et al.

NASA Image of the Day for Oct. 15th – Trigger-Happy Star Formation

Trigger-Happy Star Formation

This composite image, created using data from the Chandra X-ray Observatory and the Spitzer Space Telescope, shows the molecular cloud Cepheus B, located in our galaxy about 2,400 light years from the Earth. A molecular cloud is a region containing cool interstellar gas and dust left over from the formation of the galaxy and mostly contains molecular hydrogen. The Spitzer data, in red, green and blue shows the molecular cloud (in the bottom part of the image) plus young stars in and around Cepheus B, and the Chandra data in violet shows the young stars in the field.

The Chandra observations allowed the astronomers to pick out young stars within and near Cepheus B, identified by their strong X-ray emission. The Spitzer data showed whether the young stars have a so-called “protoplanetary” disk around them. Such disks only exist in very young systems where planets are still forming, so their presence is an indication of the age of a star system.

These data provide an excellent opportunity to test a model for how stars form. The new study suggests that star formation in Cepheus B is mainly triggered by radiation from one bright, massive star (HD 217086) outside the molecular cloud. According to the particular model of triggered star formation that was tested — called the radiation- driven implosion (RDI) model — radiation from this massive star drives a compression wave into the cloud triggering star formation in the interior, while evaporating the cloud’s outer layers.

Different types of triggered star formation have been observed in other environments. For example, the formation of our solar system was thought to have been triggered by a supernova explosion, In the star-forming region W5, a “collect-and-collapse” mechanism is thought to apply, where shock fronts generated by massive stars sweep up material as they progress outwards. Eventually the accumulated gas becomes dense enough to collapse and form hundreds of stars. The RDI mechanism is also thought to be responsible for the formation of dozens of stars in W5. The main cause of star formation that does not involve triggering is where a cloud of gas cools, gravity gets the upper hand, and the cloud falls in on itself.

Image Credit: X-ray: NASA/CXC/PSU/K. Getman et al.; IRL NASA/JPL-Caltech/CfA/J. Wang et al.