From NASA Chandra: “G292.0+1.8:: NASA’s Chandra Catches Pulsar in X-ray Speed Trap”

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From NASA Chandra

June 15, 2022

Megan Watzke
Chandra X-ray Center, Cambridge, Massachusetts
617-496-7998
mwatzke@cfa.harvard.edu

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Credit: X-ray: NASA/CXC/SAO/L. Xi et al.; Optical: Palomar DSS2

A pulsar is racing through the debris of an exploded star at a speed over a million miles per hour.

To measure this, researchers compared images of G292.0+1.8 from NASA’s Chandra X-ray Observatory taken in 2006 and 2016.

Pulsars can form when massive stars run out of fuel, collapse and explode — leaving behind a rapidly spinning dense object.

This result may help explain how some pulsars are accelerated to such remarkably high speeds.

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The G292.0+1.8 supernova remnant contains a pulsar moving at over a million miles per hour. This image features data from NASA’s Chandra X-ray Observatory (red, orange, yellow, and blue), which was used to make this discovery, as discussed in our latest press release. The X-rays were combined with an optical image from the The STScI Digitized Sky Survey, a ground-based survey of the entire sky.

Pulsars are rapidly spinning neutron stars that can form when massive stars run out of fuel, collapse and explode. Sometimes these explosions produce a “kick,” which is what sent this pulsar racing through the remains of the supernova explosion. An inset shows a close-up look at this pulsar in X-rays from Chandra.

To make this discovery, the researchers compared Chandra images of G292.0+1.8 taken in 2006 and 2016. A pair of supplemental images show the change in position of the pulsar over the 10-year span. The shift in the source’s position is small because the pulsar is about 20,000 light-years from Earth, but it traveled about 120 billion miles over this period. The researchers were able to measure this by combining Chandra’s high-resolution images with a careful technique of checking the coordinates of the pulsar and other X-ray sources by using precise positions from the Gaia satellite.

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Pulsar Positions, 2006 & 2016 (Credit: X-ray: NASA/CXC/SAO/L. Xi et al.)

The team calculated the pulsar 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. The researchers 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. This new estimate of the age of G292.0+1.8 is based on extrapolating the position of the pulsar backwards in time so that it coincides with the center of the explosion.

Several civilizations around the globe were recording supernova explosions at that time, opening the possibility that G292.0+1.8 was directly observed. 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.

In addition to learning more about the age of G292.0+1.8, the research team also examined how the supernova gave the pulsar its powerful kick. There are two main possibilities, both involving material not being ejected by the supernova evenly in all directions. One possibility is that neutrinos produced in the explosion are ejected from the explosion asymmetrically, and the other is that the debris from the explosion is ejected asymmetrically. If the material has a preferred direction the pulsar will be kicked in the opposite direction because of the principle of physics called the conservation of momentum.

The amount of asymmetry of neutrinos required to explain the high speed in this latest result would be extreme, supporting the explanation that asymmetry in the explosion debris gave the pulsar its kick.

The energy imparted to the pulsar from this explosion was gigantic. Although only about 10 miles across, the pulsar’s mass is 500,000 times that of the Earth and it is traveling 20 times faster than Earth’s speed orbiting the Sun.

The latest work by Xi Long and Paul Plucinksky (Center for Astrophysics | Harvard & Smithsonian) on G292.0+1.8 was presented at the 240th meeting of the American Astronomical Society meeting in Pasadena, CA. The results are also discussed in a paper that has been accepted for publication in The Astrophysical Journal. The other authors of the paper are Daniel Patnaude and Terrance Gaetz, both from the Center for Astrophysics.


Quick Look: NASA’s Chandra Catches Pulsar in X-ray Speed Trap

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NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

In 1976 the Chandra X-ray Observatory (called AXAF at the time) was proposed to National Aeronautics and Space Administration by Riccardo Giacconi and Harvey Tananbaum. Preliminary work began the following year at NASA’s Marshall Space Flight Center and the Harvard Smithsonian Center for Astrophysics . In the meantime, in 1978, NASA launched the first imaging X-ray telescope, Einstein (HEAO-2), into orbit. Work continued on the AXAF project throughout the 1980s and 1990s. In 1992, to reduce costs, the spacecraft was redesigned. Four of the twelve planned mirrors were eliminated, as were two of the six scientific instruments. AXAF’s planned orbit was changed to an elliptical one, reaching one third of the way to the Moon’s at its farthest point. This eliminated the possibility of improvement or repair by the space shuttle but put the observatory above the Earth’s radiation belts for most of its orbit. AXAF was assembled and tested by TRW (now Northrop Grumman Aerospace Systems) in Redondo Beach, California.

AXAF was renamed Chandra as part of a contest held by NASA in 1998, which drew more than 6,000 submissions worldwide. The contest winners, Jatila van der Veen and Tyrel Johnson (then a high school teacher and high school student, respectively), suggested the name in honor of Nobel Prize–winning Indian-American astrophysicist Subrahmanyan Chandrasekhar. He is known for his work in determining the maximum mass of white dwarf stars, leading to greater understanding of high energy astronomical phenomena such as neutron stars and black holes. Fittingly, the name Chandra means “moon” in Sanskrit.

Originally scheduled to be launched in December 1998, the spacecraft was delayed several months, eventually being launched on July 23, 1999, at 04:31 UTC by Space Shuttle Columbia during STS-93. Chandra was deployed from Columbia at 11:47 UTC. The Inertial Upper Stage’s first stage motor ignited at 12:48 UTC, and after burning for 125 seconds and separating, the second stage ignited at 12:51 UTC and burned for 117 seconds. At 22,753 kilograms (50,162 lb), it was the heaviest payload ever launched by the shuttle, a consequence of the two-stage Inertial Upper Stage booster rocket system needed to transport the spacecraft to its high orbit.

Chandra has been returning data since the month after it launched. It is operated by the SAO at the Chandra X-ray Center in Cambridge, Massachusetts, with assistance from Massachusetts Institute of Technology and Northrop Grumman Space Technology. The ACIS CCDs suffered particle damage during early radiation belt passages. To prevent further damage, the instrument is now removed from the telescope’s focal plane during passages.

Although Chandra was initially given an expected lifetime of 5 years, on September 4, 2001, NASA extended its lifetime to 10 years “based on the observatory’s outstanding results.” Physically Chandra could last much longer. A 2004 study performed at the Chandra X-ray Center indicated that the observatory could last at least 15 years.

In July 2008, the International X-ray Observatory, a joint project between European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU), NASA and Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構], was proposed as the next major X-ray observatory but was later cancelled. ESA later resurrected a downsized version of the project as the Advanced Telescope for High Energy Astrophysics (ATHENA), with a proposed launch in 2028.

European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Athena spacecraft depiction

On October 10, 2018, Chandra entered safe mode operations, due to a gyroscope glitch. NASA reported that all science instruments were safe. Within days, the 3-second error in data from one gyro was understood, and plans were made to return Chandra to full service. The gyroscope that experienced the glitch was placed in reserve and is otherwise healthy.

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [NASA/ESA Hubble, NASA Chandra, NASA Spitzer, and associated programs.] NASA shares data with various national and international organizations such as from [JAXA]Greenhouse Gases Observing Satellite.