'Black Widow' Pulsar Is Fastest Star Killer
An astronomical fishing expedition using data from NASA’s Fermi gamma ray space telescope has landed scientists a big and unprecedented catch — a neutron star spinning 390 times per second.
The pulsing neutron star, or pulsar, is not alone. Its companion is a very dense star at least eight times more massive than Jupiter but with only 60 percent of its
girth. Astronomers believe the companion, which is 30 times as dense as the
sun, is most likely the compacted remains of a star that has been orbiting the
pulsar for eons.
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Pulsars are believed to be the dense remnants of massive exploded stars.
The newly found pulsar, known as PSR J1311−3430, has been vaporizing material off its companion, speeding up the pulsar’s spin and gradually moving the stars closer together.
The pair now fly around each other in 93 minutes — faster
than any other pulsar binary found to date.
PSR J1311−3430 is a type of pulsar known as a “black widow,” because like the black widow spider, which kills its smaller male partner after mating, the pulsar may eventually completely destroy its partner.
The pair are only 1.4 times farther away from each than Earth is to the moon. The pulsar is circling at least 8,077 mph (13,000 kilometers per hour), while its lighter-weight partner flies around at 1.74 million mph (2.8 million kph).
Scientists at the Max Planck Institute in Germany credit a new computer-intensive data analysis technique for netting the rare, rapidly spinning pulsar. Previously, such objects have only been found by studying spin-impacted radio waves, not directly from gamma ray emissions.
“Our search used data collected by the gamma-ray satellite over a total of four years. Very soon after we started running the analysis, a clear signal showed up in the results. What we saw was very exciting,” lead researcher Holger Pletsch said in a press release.
Follow-up studies may shed more light on how it formed and evolved and if indeed the rapidly spinning pulsar is as unusual as it currently appears to be.
The research is published in this week’s Science.
Images: Top: Artist’s rendering of a fast-moving companion
star, right, circling around the pulsar J1311-3430, left. High-energy gamma
radiation emanating from the pulsar heats and evaporates the companion. The
blue circles around the pulsar represent its strong magnetic field. Credit:
NASA/ESA/M.J. Jee and H. Ford at JHU/ AEI/Milde. Bottom: Map of the gamma ray
sky from NASA’s Fermi space telescope. The color coding from blue to red to
yellow relates to the intensity of the gamma rays. Radiation from the plane of
the Milky Way is pictured as a horizontal band and the newly discovered radio
pulsar J1311-3430 is shown as a strong gamma ray source. Credit: AEI