Insights Current Affairs - 2019
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Scientists at NASA have discovered exotic neutron star called Magnetar named SGR 0418 by using Chandra X-ray Observatory and other satellites.
What are Magnetars?
Magnetar are the dense remains of dead stars that erupt sporadically with bursts of high-energy radiation. It is a type of neutron star with an extremely powerful magnetic field (ten to a thousand times stronger than for the average neutron star), the decay of which powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays. Because the only plausible source for the energy emitted in these outbursts is the magnetic energy stored in the star, these objects are called “magnetars.”
What is Neutron Star and how does it form?
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons,which are subatomic particles without net electrical charge and with slightly larger mass than protons. When a massive star runs out of fuel, its core collapses to form a neutron star, an ultra-dense object about 16 to 24 kilometres wide. The gravitational energy released in this process blows the outer layers away in a supernova explosion and leaves the neutron star behind.
Scientists from Peking University, Beijing, have solved a long standing enigma behind the cause that gives some tigers white fur with dark or sepia brown stripes. It has been found that a change in a single amino acid (A477V) in one pigmentation-related gene (SLC45A2) adds this attribute in some tigers like White Bengal tigers.
What forms this color?
The color of the fur, stripes and eye of the tiger is determined independently by two types of melanin — pheomelanin and eumelanin. In the case of white tigers, only the pheomelanin that produces the red to yellow colour is affected. Eumelanin gives the black to brown colour and is unaffected, the reason why the eye and hair in the stripes are dark or sepia brown.
How does it happen?
Point mutation in the amino acid partially blocks a particular channel, as a result of which the yellow pigment-forming process gets affected. Incidentally, mutations in the same pigmentation-related gene (SLC45A2) causes light skin colour in modern Europeans, as well. Mutations in the same gene causes skin lightening in some mouse, horse, and chicken, the scientists point out. As this mutation affects only the pigmentation process, it probably has no role in causing deaths.