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The Gaia telescope has opened the first single white dwarf, which is contaminated with metals. This phenomenon is quite rare, because heavy elements, in the atmosphere of a star of this type, should simply drown, sink in the deeper layers, closer to the core. The star, which opened the telescope was named GaiaJ1738-0826
This reports the research notes of the American Astronomical Society
A group of US and Canadian astronomers under the direction from Karl Melissa of the Center for Astrophysics and Space Sciences studied the latest DR2 data release of the Gaia European Space Agency telescope. The tool measured the brightness and color of 1.7 billion stars and changes these settings for 500 million objects.
Scientists have chosen star GaiaJ1738-0826 catalog based on the analysis of colors and absolute magnitudes of certain types of objects. The researchers then made spectroscopic observations of the white dwarf and found its spectral lines, which correspond to calcium (Ca II). Thus, it has been found that GaiaJ1738-0826 – white dwarf metal polluted with a radius and 0.012 to 0.6 solar masses. The effective temperature of its surface is 7050 degrees Kelvin, and a brightness of only 3.3% of the brightness of the Sun.
via GIPHY
Based on the analysis of the ratio of the concentration of calcium atoms to hydrogen atoms, astronomers have estimated that GaiaJ1738-0826 in the current state must absorb about 2600 pounds of calcium in one second. Thus, in general, the star can "eat" about 160,000 kilograms of material every second, which allows, based on previous studies, that calcium represents about 1.6% of the total of absorbed metals.
The authors note that if GaiaJ1738-0826 speed acres are 160 kilograms per second, around it, probably, there must be a debris disk. However, archival data from the "Spitzer" telescope and inspection of the VISTA Hemisphere Survey do not support this hypothesis.
What is a white dwarf? These compact stars are in the final phase of evolution. Despite the fact that many of these objects can be compared to the mass of the Sun, and their radius is almost 100 times smaller than it. Mainly in the spectrum of white dwarfs, find the lines corresponding to hydrogen and helium. The first white dwarf enriched with metals, was opened in 1917 by the American astronomer Adriaan van Maanen. At the time, it was a very unusual phenomenon: a celestial body resembled a dwarf star, but its spectrum responded to a massive and brilliant star. For a long time, the researchers tried to solve this riddle, until it came to the conclusion that in the atmosphere of a star there is a large number of metals – some heavier elements than hydrogen and helium.
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