from the do-you-know-how-fast-you-were-going? dept.
NASA's Chandra Catches Pulsar in X-ray Speed Trap
A young pulsar is blazing through the Milky Way at a speed of over a million miles per hour. This stellar speedster, witnessed by NASA's Chandra X-ray Observatory, is one of the fastest objects of its kind ever seen. This result teaches astronomers more about how some of the bigger stars end their lives.
Pulsars are rapidly spinning neutron stars that are formed when some massive stars run out of fuel, collapse, and explode. This pulsar is racing through the remains of the supernova explosion that created it, called G292.0+1.8, located about 20,000 light-years from Earth.
"We directly saw motion of the pulsar in X-rays, something we could only do with Chandra's very sharp vision," said Xi Long of the Center for Astrophysics | Harvard & Smithsonian (CfA), who led the study. "Because it is so distant, we had to measure the equivalent of the width of a quarter about 15 miles away to see this motion."
To make this discovery, the researchers compared Chandra images of G292.0+1.8 taken in 2006 and 2016. From the change in position of the pulsar over the 10-year span, they calculated it is moving at least 1.4 million miles per hour from the center of the supernova remnant to the lower left. This speed is about 30% higher than a previous estimate of the pulsar's speed that was based on an indirect method, by measuring how far the pulsar is from the center of the explosion.
The newly determined speed of the pulsar indicates that G292.0+1.8 and its pulsar may be significantly younger than astronomers previously thought. Xi and his team estimate that G292.0+1.8 would have exploded about 2,000 years ago as seen from Earth, rather than 3,000 years ago as previously calculated. Several civilizations around the globe were recording supernova explosions at that time, opening up the possibility that G292.0+1.8 was directly observed.
"We only have a handful of supernova explosions that also have a reliable historical record tied to them," said co-author Daniel Patnaude, also of the CfA, "so we wanted to check if G292.0+1.8 could be added to this group."
However, G292.0+1.8 is below the horizon for most Northern Hemisphere civilizations that might have observed it, and there are no recorded examples of a supernova being observed in the Southern Hemisphere in the direction of G292.0+1.8.