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White Dwarf Star Stein 2051 B

White Dwarf Star Stein 2051 B

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.

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    04h 31m 13s
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    +58° 58' 41"
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Camelopardalis
  • Distance
    DistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
    17 light-years, 5.5 parsecs

About the Data

  • Data Description
    Data DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
    Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
    The image was created from Hubble data from proposals 13457 and 13850 P.I. K. Sahu (STScI).
  • Instrument
    InstrumentThe science instrument used to produce the data.
    HST>WFC3/UVIS
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    Oct. 2013 - Oct. 2015
  • Filters
    FiltersThe camera filters that were used in the science observations.
    F606W (wide V), F814W (I)
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    Stein 2051 B, WD 0426+588
  • Object Description
    Object DescriptionThe type of astronomical object.
    White dwarf star
  • Release Date
    June 7, 2017
  • Science Release
    Hubble Astronomers Develop a New Use for a Century-Old Relativity Experiment to Measure a White Dwarf’s Mass
  • Credit
    NASA, ESA, and K. Sahu (STScI)

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White Dwarf Star Stein 2051 B
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

This image is a composite of separate exposures acquired by the WFC3/UVIS instrument on the Hubble Space Telescope. Two filters were used to sample different wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: cyan F606W and orange F814W.

Compass and Scale
Compass and ScaleAn astronomical image with a scale that shows how large an object is on the sky, a compass that shows how the object is oriented on the sky, and the filters with which the image was made.

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Details

Last Updated
Mar 28, 2025
Contact
Media

Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov