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『X線パルサーの発見』 [科学]


Scientists analyzing the first data from the Neutron Star Interior Composition Explorer (NICER) mission have found two stars that revolve around each other every 38 minutes. One of the stars in the system, called IGR J17062-6143 (J17062 for short), is a rapidly spinning, superdense star called a pulsar. The discovery bestows the stellar pair with the record for the shortest-known orbital period for a certain class of pulsar binary system. The data from NICER also show J17062's stars are only about 186,000 miles (300,000 kilometers) apart, less than the distance between Earth and the Moon. Based on the pair's breakneck orbital period and separation, scientists involved in a new study of the system think the second star is a hydrogen-poor white dwarf. The researchers were also able to determine that J17062's stars revolve around each other in a circular orbit, which is common for this type of system. The white dwarf donor star is a "lightweight," only around 1.5 percent of our Sun's mass. The pulsar is much heavier, around 1.4 solar masses. The stars orbit a point around 1,900 miles (3,000 km) from the pulsar, almost as if the donor star orbits a stationary neutron star, but NICER can is sensitive enough to detect a slight fluctuation in the neutron star's X-ray emission due to the tug from the donor star. Music: "Games Show Sphere 2" from Killer Tracks Credit: NASA's Goddard Space Flight Center
NASA Goddard
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『最新磁気プロセス』 [科学]


Though close to home, the space immediately around Earth is full of hidden secrets and invisible processes. In a new discovery reported in the journal Nature, scientists working with NASA’s Magnetospheric Multiscale spacecraft — MMS — have uncovered a new type of magnetic event in our near-Earth environment by using an innovative technique to squeeze extra information out of the data. Magnetic reconnection is one of the most important processes in the space — filled with charged particles known as plasma — around Earth. This fundamental process dissipates magnetic energy and propels charged particles, both of which contribute to a dynamic space weather system that scientists want to better understand, and even someday predict, as we do terrestrial weather. Reconnection occurs when crossed magnetic field lines snap, explosively flinging away nearby particles at high speeds. The new discovery found reconnection where it has never been seen before — in turbulent plasma.
NASA Goddard
nasa2017b.jpg

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共通テーマ:趣味・カルチャー