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Hubble record shows a low-brightness dwarf galaxy amidst nearby stars and distant galaxies, while observation data help astronomers measure cosmic distances and understand movements caused by gravity in large structures of the universe.
Released by NASA on May 27, 2026, the Hubble Space Telescope image shows the irregular dwarf galaxy ESO 490-017, a low-brightness star system located about 23 million light-years from Earth, in the constellation Canis Major.
Approximately 12,000 light-years in diameter, the galaxy appears discreetly in the observed field, as a faint cluster of stars seen behind brighter stars, which belong to the foreground of the scene captured by Hubble.
Dwarf galaxy ESO 490-017 appears as diffuse glow
Linked to the low surface brightness of ESO 490-017, the faded appearance makes its immediate identification difficult amidst the more luminous stars that appear in front of it, in the same direction observed by the space telescope.
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In the composition recorded by Hubble, the nearby stars stand out by the diffraction spikes, cross-shaped marks produced by the telescope’s optical system, while the dwarf galaxy emerges as a faint concentration in the dark background.
Scattered around ESO 490-017, reddish, orange, and beige points indicate much more distant galaxies, some with perceptible spiral structures even on a reduced scale in the frame released by the space mission.
This visual contrast reveals the depth of the observation, as the same image gathers stars from the Milky Way, a relatively nearby galaxy in astronomical terms, and even more remote objects in the background.
Hubble observation helps measure distances in the universe
More than a visual record, the data used in the image were part of a Hubble program aimed at studying the movement of galaxies and galaxy clusters through space, according to NASA.
On large scales, this movement occurs because matter in the universe is not distributed uniformly, which causes gravity to influence the trajectory of galaxies, galactic groups, and clusters over cosmic time.
To describe this collective movement, NASA uses the term “cosmic flow”, applied to the large structures that move under the gravitational effect of matter spread throughout the universe, including that which does not appear directly in the image.
Measuring distances accurately becomes essential in this type of study, as the actual position of a galaxy in space helps reconstruct the gravitational influence exerted by nearby and distant structures.
Red giants function as standard candles
In this measurement work, Hubble plays an important role by being able to observe individual stars in nearby galaxies, including low-mass red giants, used as a reference to estimate astronomical distances.
Known as “standard candles”, these stars serve as objects of known brightness, allowing the calculation of the distance to them when this value is compared to the brightness observed from Earth or orbiting telescopes.
In the case of ESO 490-017, the analysis of the luminosities of these red giants helps establish the galaxy’s distance with greater reliability, an essential factor for studies on the dynamics of cosmic structures.
From such measurements in nearby galaxies, researchers can create a more accurate picture of the cosmic neighborhood, a necessary step to understand how gravity shapes the movement of entire systems.
Hubble archive preserves data on local stars
In addition to contributing to the study of cosmic flow, the observation program generated a reference archive on types of stars present in local galaxies, as reported by the Hubble mission team.
This collection allows for new analyses from the same data and enhances the scientific value of the observation beyond the initial goal of measuring distances and movements on a large scale.
In the image of ESO 490-017, two central aspects of observational astronomy come together: the ability to reveal faint and distant objects and the use of these records to investigate gravitational forces that organize the universe.
Although the dwarf galaxy appears almost hidden behind brighter stars, its observation offers relevant information about the distribution of matter and the paths taken by galaxies in deep space.
The scientific role of discrete objects is also noteworthy, especially when they help to calibrate distances and understand movements involving structures much larger than the observed galaxy itself.
With instruments capable of separating individual stars in nearby galaxies, the telescope continues to contribute to measurements that support more detailed maps of the local universe and its gravitational dynamics.
Thus, ESO 490-017 ceases to be just a faint spot in the background of the sky and becomes part of a greater effort to understand how matter, gravity, and movement combine in the cosmic architecture.
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