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Mira HM Sge Compass Image

A Hubble Space Telescope image labeled “HM Sge HST WFC3/UVIS” at the top left corner. At the center of the image is a bright white star with four prominent diffraction spikes. The star is surrounded by clumpy red nebulosity. A more translucent, red finger-shaped cloud of material points upward to the star's upper right. The black background of space is sprinkled with tiny red and white stars. Near the top left corner of the image is a three-line color key: F502N (blue), F656N (green), F658N (red). At lower left, a scale bar is labeled 0.1 light-years over 6 arcsec. At bottom right, a white arrow pointing in the 9 o’clock direction is labeled E for east, while an arrow pointing in the 12 o’clock direction is labeled N for north.

A Hubble Space Telescope image of the symbiotic star Mira HM Sge with compass and scale bar. Located 3,400 light-years away in the constellation Sagitta, it consists of a red giant and a white dwarf companion. The stars are too close together to be resolved by Hubble. Material bleeds off the red giant and falls onto the dwarf, making it extremely bright. This system first flared up as a nova in 1975. The red nebulosity is evidence of the stellar wind. The nebula is about one-quarter light-year across. 

About the Object

  • R.A. Position
    R.A. PositionRight ascension – analogous to longitude – is one component of an object's position.
    19:41:57.080
  • Dec. Position
    Dec. PositionDeclination – analogous to latitude – is one component of an object's position.
    +16:44:39.81
  • Constellation
    ConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.
    Sagitta
  • 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.
    3,400 light-years
  • Dimensions
    DimensionsThe physical size of the object or the apparent angle it subtends on the sky.
    Image is about 30 arcsec across (about 0.45 light-years)

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 HST observations include those from program 16492 (S. Goldman). Image Processing: Joseph DePasquale (STScI)

  • Instrument
    InstrumentThe science instrument used to produce the data.
    WFC3/UVIS
  • Exposure Dates
    Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
    April 1, 2021
  • Filters
    FiltersThe camera filters that were used in the science observations.
    F502N, F656N, F658N
  • Object Name
    Object NameA name or catalog number that astronomers use to identify an astronomical object.
    HM Sge
  • Object Description
    Object DescriptionThe type of astronomical object.
    Symbiotic nova
  • Release Date
    June 10, 2024
  • Science Release
    NASA’s Hubble Finds Surprises Around a Star That Erupted 40 Years Ago
    Read the release
  • Credits
    NASA, ESA, Ravi Sankrit (STScI), Steven Goldman (STScI)

Downloads

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A Hubble Space Telescope image labeled “HM Sge HST WFC3/UVIS” at the top left corner. At the center of the image is a bright white star with four prominent diffraction spikes. The star is surrounded by clumpy red nebulosity. A more translucent, red finger-shaped cloud of material points upward to the star's upper right. The black background of space is sprinkled with tiny red and white stars. Near the top left corner of the image is a three-line color key: F502N (blue), F656N (green), F658N (red). At lower left, a scale bar is labeled 0.1 light-years over 6 arcsec. At bottom right, a white arrow pointing in the 9 o’clock direction is labeled E for east, while an arrow pointing in the 12 o’clock direction is labeled N for north.
Color Info
Color InfoA brief description of the methods used to convert telescope data into the color image being presented.

These images are a composite of separate exposures acquired by the WFC3/UVIS instrument on the Hubble Space Telescope. Several filters were used to sample various 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: Blue= F502N, Green= F656N, Red= F658N

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.

Related Images & Videos

An artist's concept of the symbiotic binary star system HM Sge on the black background of space sprinkled with varying sizes of red and white points of light. A white dwarf star (at top left) is pulling a stream of gas from its dust-producing red giant companion (at bottom right). That gas forms a blazing hot disk around the white dwarf, which can unpredictably undergo a thermonuclear explosion as the infall of hydrogen from the giant grows denser on the surface until it reaches a tipping point.

Nova in Binary Star System HM Sagittae (Artist's Concept)

This artist’s concept shows the nova system HM Sagittae (HM Sge), where a white dwarf star is pulling material from its red giant companion. This forms a blazing hot disk around the dwarf, which can unpredictably undergo a spontaneous thermonuclear explosion as the infall of...

At the center of the image is a bright white star with four prominent diffraction spikes. The star is surrounded by red clumps. A more translucent, red finger-shaped cloud of vertical material begins at the star's upper right, and goes a bit above it. The black background of space is sprinkled with tiny red and white stars.

Symbiotic Star Mira HM Sge

A Hubble Space Telescope image of the symbiotic star Mira HM Sge. Located 3,400 light-years away in the constellation Sagitta, it consists of a red giant and a white dwarf companion. The stars are too close together to be resolved by Hubble. Material bleeds off the red giant and...

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Details

Last Updated
Mar 06, 2025
Contact
Media

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

Science Credit

NASA, ESA, Ravi Sankrit (STScI), Steven Goldman (STScI)

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