White Dwarf Star Stein 2051 B

White Dwarf Star Stein 2051 B

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Fast Facts
News release ID: STScI-2017-25
Release Date: Jun 7, 2017
Image Use: Copyright
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Stellar Alignment Yields White Dwarf's Mass

Looks can be deceiving. In this Hubble Space Telescope image, the white dwarf star Stein 2051 B and the smaller star below it appear to be close neighbors. The stars, however, reside far away from each other. Stein 2051 B is 17 light-years from Earth; the other star is about 5,000 light-years away.

Astronomers made the Hubble observations of the white dwarf, the burned-out core of a normal star, and the faint background star over a two-year period. Hubble observed the dead star passing in front of the background star, deflecting its light. During the close alignment, the distant starlight appeared offset by about 2 milliarcseconds from its actual position. This deviation is so small that it is equivalent to observing an ant crawl across the surface of a quarter from 1,500 miles away. From this measurement, astronomers calculated that the white dwarf's mass is roughly 68 percent of the sun's mass.

Stein 2051 B is named for its discoverer, Dutch Roman Catholic priest and astronomer Johan Stein.

Gravitational Lensing, Observations, Stars, White Dwarfs


NASA, ESA, and K. Sahu (STScI)