ESA detects ‘Pulsar’ star which emits same amount of energy in 1 second released by Sun in 3.5 years
स्रोत: News Bharati English      तारीख: 22-Feb-2017

Europe, February 22:  The European Space Agency’s XMM Newton Satellite has detected – Pulsar the brightest and farthest star. Pulsars are whirling; x-ray emitting, magnetized neutron star which is 50 million light years away. Pulsar is 1,000 times brighter than previously thought and is in the spiral galaxy NGC 5907 also known as the Knife Edge Galaxy or Splinter Galaxy.The Pulsar was spotted by the XMM-Newton space observatory, a telescope that orbits the Earth and is owned by the European Space Agency. This study was published online in the journal- Science.

Embeded Object

Pulsars were once massive stars that exploded as a powerful supernova at the end of their life, before becoming small and extremely dense stellar corpses. Pulsars are spinning, magnetized neutron stars that sweep regular pulses of radiation in two symmetrical beams across the cosmos. Pulsars are gravitationally-collapsed neutron stars which, as they spin, emit beacon-like pulses of radiation in two symmetrical beams.

In one second Pulsar emits the same amount of energy released by our Sun in 3.5 years. Lying in the spiral galaxy NGC 5907 the energy this object emits in a single second is equivalent to three and a half years of energy output from our own Sun, says ESA.  The energy released by the pulsar was a surprise to astronomers: "Something else is needed in our models in order to account for the enormous amount of energy released by the object," said Gian Luca Israel of the Astronomical Observatory of Rome in Italy, lead author of the study.

"The discovery of this very unusual object, by far the most extreme ever discovered in terms of distance, luminosity and rate of increase of its rotation frequency, sets a new record for XMM-Newton, and is changing our ideas of how such objects really 'work,'" said Norbert Schartel, a European Space Agency scientist.

"Before, it was believed that only black holes at least 10 times more massive than our sun feeding off their stellar companions could achieve such extraordinary luminosities, but the rapid and regular pulsations of this source are the fingerprints of neutron stars and clearly distinguish them from black holes," says Gian Luca Israel, from INAF-Osservatorio Astronomica di Roma, Italy. The data also revealed that the pulsar’s spin rate has changed over time, from 1.43 s per rotation in 2003 to 1.13 s in 2014. The same relative acceleration in Earth’s rotation would shorten a day by five hours in the same time span.

For the pulsar just discovered, the team says the object is accreting matter from its companion, even as the neutron star rotates on its axis every 1.13 seconds. "This object is really challenging our current understanding of the 'accretion' process for high-luminosity stars," says Gian Luca. "It is 1000 times more luminous than the maximum thought possible for an accreting neutron star, so something else is needed in our models in order to account for the enormous amount of energy released by the object." Israel said that more sophisticated data analysis is needed to check for the possible presence of other hidden pulsars. ‪