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Trio of Galaxies Mix It Up
This NASA Hubble Space Telescope image shows three galaxies playing a game of gravitational tug-of-war that may result in the eventual demise of one of them.
Located about 100 million light-years away in the constellation Piscis Austrinus (the Southern Fish), the galaxy interaction may ultimately lead to the three reforming into two larger star cities.
The three galaxies – NGC 7173 (middle left), NGC 7174 (middle right), and NGC 7176 (lower right) – are part of Hickson Compact Group 90, named after astronomer Paul Hickson, who first cataloged these small clusters of galaxies in the 1980s. NGC 7173 and NGC 7176 appear to be smooth, normal elliptical galaxies without much gas and dust.
In stark contrast, NGC 7174 is a mangled spiral galaxy that appears as though it is being ripped apart by its close neighbors. The galaxies are experiencing a strong gravitational interaction, and as a result, a significant number of stars have been ripped away from their home galaxies. These stars are now spread out, forming a tenuous luminous component in the galaxy group.
Ultimately, astronomers believe that NGC 7174 will be shredded and only the two "normal" elliptical galaxies (NGC 7173 and NGC 7176) will remain.
Hubble imaged these galaxies with the Advanced Camera for Surveys in May 2006.
About the Object
- R.A. PositionR.A. PositionRight ascension – analogous to longitude – is one component of an object's position.22h 2m 5.61s
- Dec. PositionDec. PositionDeclination – analogous to latitude – is one component of an object's position.-31° 58' 0.44"
- ConstellationConstellationOne of 88 recognized regions of the celestial sphere in which the object appears.Piscis Austrinus
- 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.106 million light-years (33 megaparsecs)
- DimensionsDimensionsThe physical size of the object or the apparent angle it subtends on the sky.This image is roughly 3.2 arcminutes (1,000,000 light-years or 31,000 parsecs) wide.
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.This image was created from HST data from proposal 10554: R. Sharples (University of Durham), M. Beasley (University of California, Santa Cruz), J. Blakeslee (Dominion Astrophysical Observatory), S. Zepf and A. Kundu (Michigan State University), and J. Cho (University of Durham). - InstrumentInstrumentThe science instrument used to produce the data.HST>ACS/WFC
- Exposure DatesExposure DatesThe date(s) that the telescope made its observations and the total exposure time.May 16, 2006, Exposure Time: 1.2 hours
- FiltersFiltersThe camera filters that were used in the science observations.F850LP (z) and F475W (g)
- Object NameObject NameA name or catalog number that astronomers use to identify an astronomical object.Hickson Compact Group 90 (HCG 90): NGC 7173, NGC 7174, and NGC 7176
- Object DescriptionObject DescriptionThe type of astronomical object.Cluster of Interacting Galaxies
- Release DateMarch 3, 2009
- Science ReleaseTrio of Galaxies Mix It Up
- Credit
The image is a composite of separate exposures made by the ACS instrument on the Hubble Space Telescope. Two filters were used to sample broad wavelength ranges. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are: Red: F850LP (z) Green: F850LP (z) + F475W (g) Blue: F475W (g)
Related Images & Videos
Pan through Hickson Compact Group 90
The Hubble Space Telescope shows us what happens when a trio of galaxies mixes it up in deep space. We start with a close-up look into the core of elliptical galaxy NGC 7176. A curious bridge of stars and dark dust stretches away from the nucleus. The feature is actually a...
Pan through Hickson Compact Group 90 (Narrated Version)
The Hubble Space Telescope shows us what happens when a trio of galaxies mixes it up in deep space. We start with a close-up look into the core of elliptical galaxy NGC 7176. A curious bridge of stars and dark dust stretches away from the nucleus. The feature is actually a...
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Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
