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Dwarf Irregular Galaxy UGC 8091
The billion stars in galaxy UGC 8091 resemble a sparkling snow globe in this festive Hubble Space Telescope image from NASA and ESA (European Space Agency).
The dwarf galaxy is approximately 7 million light-years from Earth in the constellation Virgo. It is considered an "irregular galaxy" because it does not have an orderly spiral or elliptical appearance. Instead, the stars that make up this celestial gathering look more like a brightly shining tangle of string lights than a galaxy.
Some irregular galaxies may have become tangled by tumultuous internal activity, while others have formed by interactions with neighboring galaxies. The result is a class of galaxies with a diverse array of sizes and shapes, including the diffuse scatter of stars that is this galaxy.
Twelve camera filters were combined to produce this image, with light from the mid-ultraviolet through to the red end of the visible spectrum. The red patches are likely interstellar hydrogen molecules that are glowing because they have been excited by the light from hot, energetic stars. The other sparkles on show in this image are a mix of older stars. An array of distant, diverse galaxies appear in the background, captured by Hubble's sharp view.
The data used in this image were taken by Hubble's Wide Field Camera 3 and the Advanced Camera for Surveys from 2006 to 2021.
Among other things, the observing programs involved in this image sought to investigate the role that dwarf galaxies many billions of years ago had in re-heating the hydrogen that had cooled as the universe expanded after the big bang.
Astronomers are also investigating the composition of dwarf galaxies and their stars to uncover the evolutionary links between these ancient galaxies and more modern galaxies like our own.
About the Object
- R.A. PositionR.A. PositionRight ascension – analogous to longitude – is one component of an object's position.12:58:40.4
- Dec. PositionDec. PositionDeclination – analogous to latitude – is one component of an object's position.14:13:03
- ConstellationConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.Virgo
- DistanceDistanceThe 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.7.9 million light-years
- DimensionsDimensionsThe physical size of the object or the apparent angle it subtends on the sky.Image is about 2.8 arcmin across
About the Data
- Data DescriptionData 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. - InstrumentInstrumentThe science instrument used to produce the data.WFC3, ACS
- Exposure DatesExposure DatesThe date(s) that the telescope made its observations and the total exposure time.2006-2021
- FiltersFiltersThe camera filters that were used in the science observations.F218N, F225W, F275W, F336W, F373N, F487N, F475W, F502N, F656N, F657N, F814W, F110W, F160W
- Object NameObject NameA name or catalog number that astronomers use to identify an astronomical object.UGC 8091
- Object DescriptionObject DescriptionThe type of astronomical object.Dwarf Irregular Galaxy
- Release DateDecember 20, 2023
- Science ReleaseNASA’s Hubble Presents a Holiday Globe of Stars
- CreditESA/Hubble, NASA, ESA, Yumi Choi (NSF's NOIRLab), Karoline Gilbert (STScI), Julianne Dalcanton (Center for Computational Astrophysics/Flatiron Inst., UWashington)
These images are a composite of separate exposures acquired by the the Hubble Space Telescope using the WFC3 and ACS instruments. Multiple filters were used to sample broad and narrow 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: Purple (F218N, F225W, F275W), Blue (F336W, F373N, F487N), Cyan (F475W, F502N), Green (F475W), Orange (F814W), Red (F656N, F657N, F110W, F160W)
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Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
