First view of a newborn millisecond pulsar?February 13, 2002Combining Hubble Space Telescope images with radio observations has revealed a highly unusual system consisting of a fast spinning pulsar and a bloated red companion star. The existence of the system is something of a mystery - the best explanation so far is that we have our first view of a millisecond pulsar just after it has been `spun up` by its red companion star. Although more than 90 specimens of the exotic species of fast-spinning `millisecond pulsars` are known today, no observations have yet been made to back up the theory of how they reached this state. A series of observations of the millisecond pulsar PSR J1740-5340 (spinning at 274 times per second) and its companion star from the ESA/NASA Hubble Space Telescope and the Parkes radio telescope seem to show the final stage of the pulsar acceleration process for the first time. The generally favoured `recycling scenario` describing the creation of millisecond pulsars proposes that an old, slowly rotating neutron star begins to absorb matter from its elderly companion star, typically a red giant. The matter hits the surface of the neutron star and transfers energy to make it rotate faster. The process ends when the pulsar has been revitalised and is rotating at hundreds of times per second (hence a millisecond pulsar), and its companion almost emptied of matter and turned into a white dwarf. A team of scientists from Bologna Astronomical Observatory conducted a series of Hubble observations of the pulsar-companion system in the globular cluster NGC 6397. The observations show that the millisecond pulsar`s companion is not the expected white dwarf, but a bloated red star, whose radius is about 100 times greater than that of a white dwarf and at least five times greater than a normal star of similar mass! This unique couple orbit around each other in 1.35 days. The observations also indicate the abnormal presence of large amounts of gas in the system. This gas is released from the bloated companion star and soon will be swept away by the recently accelerated pulsar. Once the pulsar has been spun up it can no longer absorb gas from the companion. Lead astronomer Francesco Ferraro explains: "We have certainly discovered a very unusual pair. A system consisting of a millisecond pulsar and a star that is not a white dwarf has never been seen before. Our favoured theory is that we are seeing the system before the bloated red star has been `emptied` of gas and turned into a white dwarf. If this compelling hypothesis is wrong then the companion star could be a normal star in the globular cluster that has been captured by the pulsar by chance. Maybe it has expelled the white dwarf that we normally find in such systems." At last astronomers have observations to back the theory of millisecond pulsar births, and the discovery opens a new window on the evolution of millisecond pulsars. European Space Agency (ESA) |
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| Related Hubble Space Telescope Current Events and Hubble Space Telescope News Articles Goddard team develops new carriers for space station In a partnership that exemplifies One NASA, engineers at NASA's Goddard Space Flight Center in Greenbelt, Md. teamed up with engineers at NASA's Johnson and Kennedy Space Centers to design, build, and test five new ExPRESS Logistics Carriers, or ELCs, which will be delivered to the International Space Station. 'Dropouts' pinpoint earliest galaxies Astronomers, conducting the broadest survey to date of galaxies from about 800 million years after the Big Bang, have found 22 early galaxies and confirmed the age of one by its characteristic hydrogen signature at 787 million years post Big Bang. Opening up a colorful cosmic jewel box Star clusters are among the most visually alluring and astrophysically fascinating objects in the sky. One of the most spectacular nestles deep in the southern skies near the Southern Cross in the constellation of Crux. Scientists use world's fastest supercomputer to model origins of the unseen universe Understanding dark energy is the number one issue in explaining the universe, according to Salman Habib, of the Laboratory's Nuclear and Particle Physics, Astrophysics and Cosmology group. Rebirth of an icon: Hubble's first images since Servicing Mission 4 Astronomers today declared the NASA/ESA Hubble Space Telescope a fully rejuvenated observatory ready for a new decade of exploration, with the release of observations from four of its six operating science instruments. Astronomers discover stars in early galaxies had a need for speed A team of astronomers has measured the motions of stars in a very distant galaxy for the first time and discovered they are whizzing around at astonishingly high speeds-about one million miles per hour, or twice the speed at which the Sun circles our own Milky Way galaxy. Dark Energy From the Ground Up: Make Way for BigBOSS Several ways have been proposed to examine dark energy, in hopes of finding out just what it is. One of them, "supernovae" for short, certainly works: it's how dark energy was discovered in the first place. Other independent techniques, such as weak gravitational lensing and baryon acoustic oscillation, also promise great power but are as yet unproven. Hubble captures rare Jupiter collision The checkout and calibration of the NASA/ESA Hubble Space Telescope has been interrupted to aim the recently refurbished observatory at a new expanding spot on the giant planet Jupiter. NASA celebrates Chandra X-Ray Observatory's 10th anniversary Ten years ago, on July 23, 1999, NASA's Chandra X-ray Observatory was launched aboard the space shuttle Columbia and deployed into orbit. Jupiter pummeled, leaving bruise the size of the Pacific Ocean Something slammed into Jupiter in the last few days, creating a dark bruise about the size of the Pacific Ocean. More Hubble Space Telescope Current Events and Hubble Space Telescope News Articles |
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