admin NASA’s Hubble Space Telescope has directly quantified the mass of a white dwarf for the first time ever.
White dwarfs are the surviving cores of sun-like stars that have burned out. Astronomers now use Hubble to measure the mass of a single, isolated white dwarf known as LAWD 37, and find it to be 56% the mass of the Sun.
LAWD 37, the collapsed remnant of a star that burned out a billion years ago, has been extensively studied because it is close to Earth and only 15 light-years away in the constellation Muska.
This study supports previous theoretical predictions about white dwarf mass and current theories about how stars evolve as the end product of typical stellar evolution.
“This white dwarf is relatively close to us, so we have a lot of data about it,” says Peter McGill of the University of California, the study’s lead author. I have information about.” commented.
The study “First semi-empirical test of white dwarf mass-radius relationship from a single white dwarf using astronomical microlensing” is published in the Royal Astronomical Society monthly notice. .
Gravitational microlensing was the key to the discovery
Previously, scientists could only measure white dwarfs in binary star systems. Because simple Newtonian physics can be used to measure the mass of two stars orbiting in the same orbit. However, when the white dwarf’s companion star is in a long-term orbit of hundreds or thousands of years, these measurements become uncertain. Telescopes can only easily analyze the orbital motion of stars.
To measure stars without companions, the researchers used gravitational microlensing. Light from a background star is slightly deflected by the foreground dwarf due to distortions in gravitational space, and when a white dwarf passes in front of a background star, the star is momentarily displaced from its actual position in the sky due to microlensing effects. It looked out of place.
Hubble measures mass of white dwarf star for first time I was able to predict when it would pass.
Hubble was then able to measure precisely how the positions of background stars in the night sky shifted momentarily over the next several years.
“These events are rare, and so are their effects,” McGill said. “White dwarf glare – 400 times brighter than background stars. Only Hubble can make such high-contrast observations in visible light.
“The accuracy of LAWD 37’s mass measurements allows us to test the relationship between mass and radius for white dwarfs,” added McGill. “It means testing the theory of degenerate matter (gas compressed by gravity and behaving like solid matter) under extreme conditions inside this dead star.” We’ve come to the conclusion: “Gaia really changed the game” – it’s interesting to be able to use Gaia data to predict when an event will occur and then watch it. ” We will continue to measure the gravitational microlensing effect and hope to measure the masses of many more types of stars. “
