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Journalism of Courage
Take a look at the essential concepts, terms, and phenomena from the static and current parts of the UPSC-CSE.
Word: White dwarf
Subject: Science (Space)
(Relevance: High value for prelims. General, as well as conceptual questions, can be asked as it is in news due to a first-time observed phenomenon of “cosmic cannibalism”.)
Why in news?
—Astronomers have observed for the first time a phenomenon, called, “cosmic cannibalism,” a dead star is ripping apart its planetary system. A star is ending its life so violently that the dead star left behind, called a white dwarf, is disrupting an entire planetary system by sucking in debris from both its inner and outer reaches.
—The white dwarf star is consuming the rock-metallic and icy material, both of which are the “ingredients of planets”.
What is a white dwarf?
—A white dwarf is formed when a low-mass star like our sun exhausts most of its nuclear fuel. It is usually very dense, dim and about the size of a planet. It is the last observable stage of evolution for low- and medium-mass stars.
—Compared to our sun, a white dwarf has a similar carbon and oxygen mass though it is much smaller in size — similar to Earth. White dwarf temperatures can exceed 100,000 Kelvin according to NASA. Despite having too high a temperature, white dwarfs have a low luminosity as they’re so small in size.
—Where a star ends up at the end of its life depends on the mass it was born with. Stars that have a lot of mass may end their lives as black holes or neutron stars. A low or medium mass star (with a mass less than about 8 times the mass of our Sun) will become a white dwarf. A typical white dwarf is about as massive as the Sun, yet only slightly bigger than the Earth. This makes white dwarfs one of the densest forms of matter, surpassed only by neutron stars and black holes.
What else you should know?
—This case of cosmic cannibalism was diagnosed with the help of archival data from the Hubble Space Telescope and other NASA observatories.
—The researchers obtained the findings based on the analysis of material captured by the atmosphere of the nearby white dwarf star G238-44.
(source: nasa.gov)
Point to ponder: What does the new study of cosmic cannibalism confirm and why are the scientists finding the research findings interesting?
