The NASA/ESA Hubble Space Telescope has captured a stunning view of NGC 2775, a galaxy that leaves astronomers puzzled. Located about 67 million light-years away in the constellation Cancer (the Crab), this galaxy refuses to fit neatly into one category.
At its core, NGC 2775 has a smooth, featureless center devoid of gas, a trait typical of elliptical galaxies. Yet, surrounding this calm heart lies a dusty ring with patchy star clusters, a hallmark of spiral galaxies. The result is a mysterious mix — is it spiral, elliptical, or something in between?
Spiral, Elliptical, or Lenticular?
Because astronomers can only view NGC 2775 from one angle, its classification remains tricky. Some researchers label it a spiral galaxy due to its feathery ring of stars and dust. Others suggest it belongs to the lenticular galaxy category — galaxies that share traits with both spiral and elliptical systems.
Lenticular galaxies may form in different ways:
- Spirals that merged with other galaxies.
- Systems that ran out of star-forming gas and lost their spiral arms.
- Ellipticals that later collected gas and developed a disk.
Signs of a Mysterious Past.
Hints of NGC 2775’s history suggest galactic mergers. Invisible in Hubble’s image but detected by astronomers, a hydrogen gas tail nearly 100,000 light-years long stretches around the galaxy. This faint structure may be the remains of one or more galaxies torn apart and absorbed by NGC 2775, explaining its unusual features.
Flocculent Spiral Galaxy.
Despite the debate, most astronomers classify NGC 2775 as a flocculent spiral galaxy. Unlike grand design spirals with clear arms, flocculent spirals display feathery, discontinuous “tufts” of stars loosely forming spiral structures.
Hubble’s New Look at NGC 2775.
Hubble previously released an image of NGC 2775 in 2020. The new version includes observations of red hydrogen light, emitted by clouds of gas around massive young stars. In the image, these appear as bright, pinkish clumps, highlighting regions where new stars are actively forming.
With each observation, NGC 2775 continues to challenge astronomers’ understanding of galaxy formation and evolution, standing as a cosmic blend of mystery, beauty, and science.
